Method for Installation of DB or Panel-(Part-2)


(4) ELECTRICAL CHECKS BEFORE CHARGING THE  PANEL

  • TESTING CONTINUITY BETWEEN ALL METAL PARTS AND GROUND
  • For performing this test, it is generally recommended to use a milliohm meter for continuity measurement.
  • INSULATION RESISTANCE TESTS For SWITCHGEAR
  • It is recommended to perform these tests before connection starting so all isolating devices will be closed.
  • If cables are already connected, open the isolating devices before any test.
  • Disconnect the ground sensing device and the control cables.
  • Using a 1000 V DC megohmmeter, measure the insulation resistance after a one minute Electrification time between :
  • 1) Phase to Phase
  • 2) Phase to Neutral
  • 3) Phase to Ground
  • 4) Ground to Earth
  • Using a 500 V DC megohmmeter, measure the insulation resistance after a one minute electrification time between:
  • 1) Auxiliary circuit and ground.
  • Reconnect the cables after testing.
  • Control Wiring Electrical Tests for Switchgear and Switchboards
  • Perform insulation-resistance tests on control wiring with respect to ground. Apply 500 volts dc for 300-volt rated cable and 1000 volts dc for 600-volt rated cable for one minute each.
  • Important: Units with solid-state components could be damaged if not properly isolated (via removal of plugs and/or fuses) before applying test voltage. Be sure to follow all manufacturers’ recommendations when performing dielectric tests on solid state components
  • Minimum insulation-resistance values of control wiring should be comparable to previously obtained results but not less than two megohms.

Charging & Testing of Panel:

  •  Cable Terminations:
  • Identify cable to be laid and Cut the cable to required length.
  • Put temporary marker onto the cable.
  • Carefully pull (using suitable method) and lay the cable to its route
  • Make appropriate opening (Cut-out) in DB /PANEL for inserting the cable with a rubber gasket so that there will be no sharp edges and secure the wire insulation from damage.
  • Gland the cables using appropriate cable glands size.
  • Terminate cables inside enclosure by securing cables to switchboards with gland bracket; and enclosure with glanding plates or fabricated steel extension boxes.
  • Slice the cable and identify cores to be used. Installed the ferrule number and cable lug
  • Dressing the cable inside the panel and Secure the cables (if necessary) with cable ties or other suitable method
  • Install cable marker / tag as specified
  • Terminate the cable properly & as per termination schedule
  • Earth the glands to the equipment earth grid
  • After complete termination of wire/cable same DB compartment shall be cleaned and fixed door.
  • Earthing Connections:
  • The Panel Main earthing bar is to connected to earth electrode or earthing Grid by Suitable size of 2 No’s of Eathing Strip or Earthing Wire via testing joints.
  • Energize the Panel
  • Switch off All Switchgear of Panel.
  • Connect the incoming cables of Panel to the Power Supply Source.
  • Check healthy ness of Power Supply at incoming of Panel.
  • NO LOAD:
  • Measure input Voltage of Power Supply between Phase to Phase, between Phase and Neutral and between Neutral and Ground.
  • If measured incoming Voltage is within limit than Switch ON the Main Breaker of Panel.
  • Measure Voltage on Bus bar between Phase to Phase, between Phase and Neutral and between Neutral and Ground.
  • If measured Bus bar Voltage is within limit than Panel should operate on NO LOAD Condition for 5 minutes to observe any heating, sparking and performance of accessories of Panel.
  • After 5 minute, one by one Switch ON the all Circuit Breaker of Panel.
  • ON LOAD:
  • Measure Voltage on each outgoing feeder of panel between Phase to Phase, between Phase and Neutral and between Neutral and Ground.
  • If measured Voltage of outgoing feeders are in within limit than Panel should Energize for 2 hours and verify complete performance. Check for any unusual temperature rise in cables, terminals and protective devices.
  • Correct Phasing:
  • Check Phase Sequence of Power Supply at Outgoing Circuit of Panel.
  • If there is not correct phase sequence for three phase power supply, reverse one phase at incoming side of Panel.
  • Indicators
  • Check all Power Supply ON /OFF / TRIP indicator works properly.
  • If any associated converters check the indications to the corresponding output terminal block.
  • Under/Overvoltage Protection
  • Check the relay operation and adjust to the desired rating.
  • The protection information reports shall be checked up to the distribution board output terminal block.
  • Automatic Transfer Switches
  • Check mechanical and / or electrical interlocks.
  • With the both available supplies (Main Power & D.G Power) confirm the functional checks by presence of voltage, loss of supply, restoration of supply in manual and in automatic mode.
  • The both incoming supplies are readiness in the distribution board
  • Record The Test Data:

Floor Marking Near Electrical Panels:

  • Keep Space in Front of Electrical Panels Clear
  • The area in front of electrical panels must be kept clear and marking with effective floor marking taps.
  • While specific colors of floor marking tape are not required, it’s often recommended that employers select colors that indicate a hazard is present. Striped black and yellow floor marking tape often serves this purpose, as black and yellow are regularly used for hazard markings.
  • When the nominal voltage to ground for a piece of electrical equipment is 600 volts or less, the minimum depth of clear working space in front of the equipment must be 3 feet (in some circumstances, it must be larger). This distance applies to some situations involving voltages up to 2500 volts as well. 

Picture1

Codes and Standards:

  • Panel shall comply with the latest Relevant Indian Standards and Electricity Rule and Regulations and shall be as per IS-13947-1993.
  • The general construction shall confirm to IS-8623-1977 (Part-1) for factory built assembled switchgear & control gear for voltage up to and including 1100 V AC.

FLOW CHART:

Picture2

Method for Installation of DB or Panel-(Part-1)


Purpose:  

  • This method of statement describe the procedure for safely installation and testing of DB and LV Panel as per contract specification and as per the standard Practice and Code.

General Equipment & Tools:

  • The equipment that will be engaged for Installation of Panel ,D.B will be
  • Tool Box with Screwdriver, Pliers, Spanner , Hammer
  • Drilling Machine with various Bits , Grinding & Cutting Machine
  • Electrical Tester , Continuity Tester ,Multi Meter , Earth Tester , IR Tester
  • Wire Cutter , Blower ,Crimping Tools
  • Knockout punch and Flat File
  • Marker, Measuring tape, Level gauge / Spirit level.
  • Ladder / Scaffolding / Mobile scaffold
  • Chain Block and Pipe Wrench
  • Portable Lights
  • Removable Barricades

Storage & Material Handling:.

  • Suitable lockable storage shall be made on Site.
  • The storage area must be free from dust and Water leakages / seepages.
  • The DB, Panel and Accessories shall be unloaded with care in designated area of the Store to avoid any damages and against the effects of weather or any construction activities of Site.
  • The Material will be stacked / unload in the site store on a proper stand on wooden loft on a flat surface at a sufficient height from Ground.
  • Materials shall be stored in a place free of water and adequately covered to avoid any kind of damages.
  • Proper protection should be given to the material by means of covering the material with Tarpaulin sheet etc.
  • If they are dispatch in packs or pallets, each pack of pallet shall be lifted individually with suitable lifting equipment.
  • The material shall be transported / Shifted in their original packing to Site location.

Inspection of Materials:

  • Inspection of Materials:
  • Check the reference of delivered material against approved submittal and purchase order.
  • Check The Material according to its Type, Size, Make
  • Physical Damages Inspection:
  • In case of any damages observed during inspection, the concern report will be issued and Material shall be returned to the supplier for replacement.

Sequence of Installation Works:

(1) Shifting of Panel on Site

  • Prior to commencement of Panel installation works, areas and access shall be checked and confirmed by safety officer, that they are in a suitable Condition for installation works.
  • Decide appropriate Size of Crain / Hydra according to weight of Panel.
  • Panel shall be carefully unloaded or shifted to the site by using Crane/Hydra or by sufficient manpower and moved to a defined installation location.
  • Remove the packing and ensure that the panel is free from transportation damages
  • Check The shop drawings, Material submittals, Method statement, ITP & HIRA are approved,
  • Ensure all contents are available inside the panel.
  • Ensure control wiring identification shall be correctly done.
  • Megger shall be used having a valid calibration certificate.

1

(2) Installation of Panel:

  • Marking of Panel Position:
  • For floor mounted panel, the exact location of the panel and fixing holes to be marked on the concrete plinth for the installation.

2

  • Remove the Factory packing and ensure that the LT panel is free from transportation damages

3

  • Install the panel in proper alignment and fix properly.

4

  • To secure panel base to the floor using M12 anchor bolts.
  • Access around the panel to be checked for future maintenance as per regulations.
  • Ensure the services contains water is away from the panel or properly protected against any accidental leakages.
  • Incoming and outgoing cables shall be marked/identified as per approved shop drawing.
  • Mark the fixing position of the DB’s support as per approved shop drawing and coordinate with other equipment and services.
  • After marking are then drilled according to the selected sizes of anchor bolts to appropriate depth as per approved shop drawing.
  • Locknuts on the anchor bolts will ensure a permanent fixing of the DB support to the wall/slab.
  • After installation of DB supports, installing position of the DB as per approved shop drawing.
  • Ensure that painting of the wall is completed prior to marking and mounting of DB.
  • All DBs wall mounting and floor mounted arrangement will be in accordance with approved shop drawings and the approved material submittal.
  • If there is more than one DB to be installed at the same location, they shall be installed side by side and clearance shall be maintained as per approved shop drawing.
  • The height of Distribution Board shall be maintained as per approved shop drawing so that easy access for termination of cables and other maintenance work can be carried out.
  • Check the position according to the approved shop drawings.
  • Check & ensure adequate space is available for maintenance
  • After installation, the panel shall be properly cleaned and protected to prevent dust & contamination.
  • Before beginning installation in any area, examine all adjoining works in that area should be completed. Installation shall not proceed in that area until such conditions are corrected by the contractor.
  • Fix all equipment independently of wiring system. Use cadmium of zinc electroplated bolts, nuts, washers and screw.
  • Mount single DB at 1800mm from finish floor level to top of equipment, unless shown otherwise on drawing / schedules.
  • Ensures that clearance in front of switchgear is not less than 1m, or as indicated.
  • For flush installation, DB’s all conductors shall terminate behind the board in an adaptable box.
  • For surface mounting, trunking shall be fixed between the board and ceiling or floor level, or conduit run directly into Trunking which prevent correct installation of the Trunking lid.
  • The panel with plywood will be pushed towards the trolleys inside substation Room
  • When the panel reaches on the trolleys inside the substation room. Push the panel to the location where need to install .
  • To set up the chain block support to fix the chain block.
  • When the panel reaches the actual installed location, lifting-up of panel by using of chain block. Lift the panel on the panel base
  • If Panel is in section wise
  • Position the first section panel on the fixing channel & check the leveling by using the level bar & adjusting with liners.
  • To secure panel to the panel base using M12 anchor bolts.
  • To rack in the correct breaker & PT to the correct panel.
  • Proceed in the same manner for the second sections.
  • Position the second section next to the first panel.
  • Secure the second section to the panel base using two M12 anchor bolts
  • Interconnect & fasten the two section units together.
  • Proceed in the same manner for the other sections.

(3) Non Electrical checks before Charging Panel:

 (a) General Checking of Panel:

  • Confirm label/marking to ensure that is the Panel is correct according to the approved shop drawings.
  • All components (Circuit Breakers, Relays, Voltmeter and Ammeter) of the panel shall be verified against the approved panel / Technical drawing as per correct in Numbers, rating & size.
  • Ensure all contents are available inside DB.
  • Check that it is not possible to come into contact with energized equipment when working on the system.
  • If there are any Correction or modification than Check All internal connections/modification will be carried out by the Manufacturer.
  • Check the main bus bar and auxiliary circuits (control, monitoring, alarm, and fault) for continuity.
  • All breakers (incoming/outgoing) shall be in “OFF” position and to be locked to prevent mishandling

(b) Visual Checking of Panel:

  • Ensure the absence of all foreign bodies inside the switchboard.
  • Identifications labels of approved engraved type nameplate shall be fixed on DB.
  • Check the compliance with the protection index (leak tightness of the functional units, various sealing points, etc.).
  • Check the Continuity of grounding bus bar to the main earthing system.
  • Check that the panel hinged doors are connected to the frame by earthing braids.
  • Adequate earth continuity shall be made between the various components.
  • Check the door locks for correct operation
  • Check the connections for conformity with the reference drawings.
  • Check Continuity of Main, Auxiliary, Eathing and Neutral Busbar with respect to incomer and outgoing Circuits.
  • Check the connections for conformity with the reference drawings and their tightness.
  • Number terminals, cables and component parts to correspond with manufacturer have certified drawings.
  • Ensure that vents are clear and filters are in place. Screens covering ventilation openings should be in place to prevent entry of rodents or small animals.
  • Check the outer appearance (absence of any traces of shocks, peeling paint) -carry out any touch-ups if needed.

(c) Mechanical Checking of C.B:

  • Check for correct racking in and Out for circuit breaker and check :
  • That it is impossible to rack in a circuit breaker in the closed position.
  • That it is impossible to close a circuit breaker not correctly racked in.
  • That it is impossible to rack out a circuit breaker is in ON condition.

(d) Tightness of all Connection of Switchgear.

  • Fully tight all Bolted electrical connections of Electrical Switch gear of Panel.
  • Loose bolted electrical connections can lead to higher energy consumption and eventual equipment failure if not properly addressed.
  • Loose control, Power wires can lead to spark, over heat which turns in to catastrophic failure.
  • Check that all wiring connections are tight and that wiring is secure to prevent damage during routine operation of moving parts, especially when removing draw-out circuit breakers or opening and closing cubicle doors.
  • Gently tug on control wires to ensure a tight connection or use a screwdriver to gently verify torque on the connection. Infrared scans are also very effective for finding loose wires in control circuits.
  • Tighten all the connections as required

(d) General Wiring Checks for Switchgear

  • Wire inserted in the Panel will be cross-checked for existing circuit number done and final ferruling shall be done as approved shop drawing. 
  • Wire in Panel shall be used cable tie and dress with bunching of the phase-neutral and earth and lugged to the respective MCBs and Bus bar as per approved shop drawing.
  • Bunching shall be done as per phase separation respectively R, Y and B.

(e) Moving Parts and Interlock Checks for Switchgear

  • Confirm the correct operation and sequencing of electrical and mechanical interlock systems. Attempt closure on locked-open devices and attempt to open locked-closed devices.

(f) Lubrication of Switchgear and Switchboards

  • Check for appropriate lubrication on moving current-carrying parts and moving/sliding surfaces to keep everything operating smoothly. This includes hinges, locks, and latches.

(g) Insulators and Barrier Checks for Switchgear

  • Tracking is an electrical discharge phenomenon caused by electrical stress on insulation. This stress can occur phase-to-phase or phase-to-ground. Although tracking can occur internally in certain insulating materials, these materials as a rule are not used in medium- or high-voltage switchgear insulation. Tracking, when it occurs in switchgear assemblies, normally is found on insulation surfaces.
  • Electrical insulators should be inspected for evidence of physical damage or contaminated surfaces. Damage caused by electrical distress is normally evident on the surface of insulating members in the form of corona erosion or markings or tracking paths.
  • Inspect barrier and shutter assemblies for proper installation and operation. All active components should be exercised, mechanical indicating devices should be inspected for correct operation.

(h) Moisture and Corona Inspections for Switchgear and Switchboards

  • If corona occurs in switchgear assemblies, it is usually localized in thin air gaps that exist between a high-voltage bus bar and its adjacent insulation or between two adjacent insulating members. Corona might also form around bolt heads or other sharp projections that are not properly insulated or shielded. Corona in low-voltage switchgear is practically nonexistent.
  • Inspect for evidence of moisture or corona when performing maintenance inspections. On outdoor assemblies, roof or wall seams should be checked for evidence of leakage, and any leaking seams should be sealed with weatherproof caulk.

Quick Reference -Earthing


Hot dip galvanization. (IS 2629)

Galvanizing

Minimum thickness:

Min. weight:

MS flats 5mm thick & over

75 microns (minimum)

610 gms. / sq. mtr.

MS flats under 5mm thickness

60 microns (minimum)

460 gms. / sq. mtr.

Pipes/ conduits with thickness  & over 5 mm

75 microns (minimum)

610 gms. / sq. mtr

Pipes/ conduits with thickness under 5mm

60 microns (minimum)

460 gms. / sq. mtr

GI Wire

20 Microns (Medium coated)

150 gms. / sq. mtr.

 

OVERLAPING OF EARTHING STRIP

Size of Earthing Strip

Minimum Over Laping

20×3

20MM

20×6

20MM

25×3

25MM

25×6

25MM

32×6

25MM

40×5

50MM

40×6

50MM

50×6

50MM

50×10

50MM

75×6

50MM

75×10

50MM

 

NO’S AND SIZE OF NUT BOLT FOR JOINTING EARTHING STRIP

Size of Earthing Strip

Minimum Nut Bolt Required

Minimum Size of Nut Bolt

20×3

2 NO’S

8X25MM

20×6

2 NO’S

8X25MM

25×3

2 NO’S

8X25MM

25×6

2 NO’S

8X25MM

32×6

2 NO’S

8X25MM

40×5

4 NO’S

8X25MM

40×6

4 NO’S

8X25MM

50×6

4 NO’S

10X25MM

50×10

4 NO’S

10X25MM

75×6

4 NO’S

10X25MM

75×10

4 NO’S

10X25MM

 

Weight of G.I. wire  (Steel Tube India)

Gauge Gms.

mm

Weight Kg / Meter.

4

5.892

0.216

6

4.876

0.148

8

4.064

0.103

10

3.251

0.066

12

2.641

0.045

14

2.032

0.026

16

1.625

0.017

 

Weight of G.I Flat Strip

Sizes in (HxW)

Kgs/Per meter

Application

20×3 mm

0.49

Lighting Arrestor

20×6 mm

0.98

PLC Panel

25×3 mm

0.6

 

25×5 mm

0.97

 

25×6 mm

1.3

Control & Relay Panel

32×5 mm

1.21

Lighting Panel & Local Panel

32×6 mm

1.625

Distribution Board

40×3 mm

0.964

Motors 5.5kw-55Kw

40×5 mm

1.476

 

40×6 mm

1.92

HT switchgear, structures, cable trays & fence, rails, gate and steel column

50×3 mm

1.28

50×5 mm

1.92

50×6 mm

2.56

50×10 mm

4

Transformers Substations

62×6 mm

3.07

65×10 mm

5.2

75×10 mm

6

75×12 mm

7.2

 

Method for Installation of Cable Tray-(PART 2)


  • Horizon Tee Support: NEMA Standard
  • Supports for horizontal tee fittings should be located at a distance, no greater than 610 mm (24″) from each end of the fitting on the attached ladder. Fitting should also be supported once on each side rail. For 305 mm (12″) radius tees, place supports no greater than 610 mm (24″) from each end of the fitting on the attached ladder.

1

  • Horizon Cross Support: NEMA Standard
  • Supports for horizontal cross fittings should be located at a distance, no greater than 610 mm (24″) from each end of the fitting on the attached ladder.
  • Fitting should also be supported once on each side rail. For 305 mm (12″) radius cross, place supports no greater than 610 mm (24″) from each end of the fitting on the attached ladder.

2

  • Reducer Support: NEMA Standard
  • Place horizontal supports (2) at a distance no greater than 610 mm (24″) from each end.

3

  • Horizontal Y Support: NEMA Standard
  • Place horizontal supports at a distance no greater than 610 mm (24″) from each of the three openings and at the midpoint of the fitting at 22.5°

 4

  • Vertical Inside / Outside Support: NEMA Standard
  • Vertical cable tray elbows at the top of runs should be supported at each end. At the bottom of runs, they should be supported at the top of the elbow and within 610 mm (24″) of the lower extremity of the elbows. Both Inside and Outside Fittings should be additionally supported at a distance no greater than (24″) from each end.

5

  • Offset Reducing Connection & Tray to Box / Floor Connection:

6

(IV) Cable Tray Installation:

  • Ensure that the Cable Tray’s, dimension, elevation and other fittings are properly leveled and that they are coordinated to the other services fixtures.
  • The width of Cable Tray/trunking/ladder should have sufficient width to take the cable without crowding and shall allow for future 25% space. The cables should not be stacked together.
  • If the conductors carried by trays or ladders are of various systems, the ELV and data processing or different insulation, the cable ladder or trays should be separate. Use insulating barriers where it is necessary. However, approval from the engineer is required.
  • Earth continuity shall be ensured throughout the length of the Trays and Trunking
  • Cable Tray Installation on Roof / Floor:
  • Cable tray should not be laid directly on the floor or roof.
  • Cable trays installed on roof shall be supported using Gl brackets or concrete blocks.
  • It should be mounted far enough off the floor or roof to allow drainage of water.
  • The cables to exit through the bottom of the cable tray.
  • Where cable trays are installed in roof or exposed to sunlight, factory made cover shall be fixed to protect the cables from direct sunlight.
  • Cable Trunking runs shall be arranged so that the lid is always on top or side. Lid shall be fixed to the trunking using factory made quick fix type clips.
  • Open ends of the trays / trunkings shall be capped with purpose made end caps.
  • Cable Tray Accessories:
  • Where cutting of the trays is needed, circular saws will be used. Cable tray cut edges will be rasped or welded if it is necessary, galvanized points will be cleaned then it will be sprayed with galvanizing spray immediately.
  • Cut portion of Trays and Trunking, shall be made free of sharp edges by filing and coated with zinc rich and top coat and jointed using fish-plates with bolts and nuts.
  • Any cutting on the cable tray to be done along the solid area and not across the perforation of the cable tray. Burrs needs to be removed and cuts need to be protected with anti-rust galvanized paint to prevent rust.
  • The minimum radius of Cable Tray should equal the minimum bending radius of the cables. Depending on the number of cables to be placed in the system it may be advantageous to use the next highest radius.
  • Installation of splice connectors
  • Splice connectors shall be located as recommended by the manufacturers.
  • Splice joints should be designed and placed so as to maximize the rigidity of the cable tray.
  • Splice connectors shall be attached by round / Hexa head bolts with the nuts and washers located on the outside of the tray or ladder unless otherwise specified by the manufacturer.
  • Thermal expansion splices shall be installed wherever expansion joints occur.

7

  • All straight joints, bends and offset connections shall be made neatly using standard fittings (fish plate and coupler). Only when these are inappropriate, fabricated bends/offsets shall be used.

(5) Cleaning of Work Area:.

  • There should be a visual inspection of the trunking from inside side after installation. This is to be sure that it is free from Debris, burrs and waste materials.
  • There are no sharp edges that could cause damage to the cables during installment.
  • Galvanized coating damaged by excessively rough treatment during transit and erection shall be repaired using at least two coats of good quality zinc-rich paint complying with BS 4652.
  • Upon completion of installation of cable trays/trunking in one area, the completed work shall be presented for Inspection and shall be protected by providing polyethylene sheet cover.

(6) Codes and Standards:.

  • IS 4759: Hot-dip zinc coatings on structural steel and other allied products 
  • IS 2629: Recommended Practice for Hot-Dip Galvanizing of Iron and Steel
  • IS 2633: Methods for testing uniformity of coating of zinc coated articles
  • IEC 61537 Cable Management- Cable Tray System and Cable Ladder System
  • BS 4652 Specification for zinc-rich priming paint
  • National Electrical Manufacturers Association (NEMA) Standard

8

Method for Installation of Cable Tray-(PART 1)


(1) Purpose:

This method explains the Procedures or sequence of activity for safely installation and Testing of cable tray, and it’s accessories as per the standard Practice and Code.

(2) General Equipment & Tools: . 

  • The equipment that will be engaged for Installation of Cable Tray will be
  • Tool Box with Screwdriver, Pliers, Spanner , Hammer
  • Drilling Machine with various Bits , Grinding & Cutting Machine
  • Electrical Tester , Continuity Tester ,Multi Meter
  • Cutter , Blower
  • Knockout punch and Flat File
  • Galvanizing paint
  • Marker, Measuring tape, Level gauge / Spirit level.
  • Ladder / Scaffolding / Mobile scaffold
  • Chain Block and Pipe Wrench
  • Portable Lights
  • Removable Barricades

(3) Storage & Material Handling: .

  • The storage area must be free from dust and Water leakages / seepages.
  • Manufacturer recommendation shall always be followed in loading/unloading and storing of Material.
  • Material and its accessories shall be unloaded handle with care in designated area of the Store (Do not directly drop to Ground) to avoid any damages.
  • Materials shall be stored in a dry place which is free from water or from weather effects and protection should be given to the material by means of covering the material with Tarpaulin sheet.
  • The Material will be stacked / unload in the site store on a proper stand on wooden loft on a flat surface at a sufficient height from Ground.
  • If Material are dispatch in packs or pallets, each pack or pallet shall be lifted individually with suitable lifting equipment.
  • The material shall be transported / Shifted in their original packing to Site location.
  • The Material should be visually inspected for damage, which may have occurred during transport.
  • When bringing down materials, they should be handled with care and lowered carefully to the ground. They should not be dropped.

  • To prevent damage to cable tray, never pull cable tray from a truck trailer by chaining to the bottom rung and dragging cable tray out of the trailer

  • If the Material is found defective it shall not be installed and the cable shall be returned to the supplier for replacement.
  • Cable Tray and its accessories (pre-galvanized, hot dipped galvanized) shall be stored in a dry place, fully enclosed / ventilated store.

(4) Inspection of Materials:

  • Check The Material according to its Type, Size, Make
  • Visual inspection:
  • Type of Cable Tray
  • Type of Cable Tray Material
  • Type of Cable Tray Coating
  • Standard width of Cable Tray
  • Standard length of Cable tray
  • Cable Tray thickness
  • Flange height of Cable Trays
  • Proper painting / Galvanization and identification numbers of the cable trays
  • Physical Damages Inspection:
  • Damage on trays and ladders
  • Damage on galvanizing
  • Fittings and accessories are of proprietary type
  • Testing of galvanizing:
  • Uniformity of coating Thickness Test
  • Electrical continuity of connection
  • TRs not more than five year old from date of purchase order shall be reviewed for acceptance. Otherwise test shall be carried out.

BS EN ISO 1461

Table-1 Control Sample Size Related to Lot Size

Number of Lot

Min. Sample

1 To 3

All

4 To 500

3

501 To 1200

5

1021 To 3200

8

3201 To 10000

13

>10000

20

Inspection Lot: Single Order or Single Delivery Order

 

ISO 1461:2009 TABLE-3

Minimum coating thickness and mass on samples that are not centrifuged

Article and its thickness

Local coating thickness (minimum)µm

Local coating
mass
(minimum)g/m2

Mean coating thickness (minimum)µm

Mean coating
mass
(minimum)g/m2

Steel > 6 mm

70

505

85

610

Steel > 3 mm to < 6 mm

55

395

70

505

Steel > 1.5 mm to < 3 mm

45

325

55

395

Steel < 1.5 mm

35

250

45

325

Casting > 6 mm

70

505

80

575

Castings < 6 mm

60

430

70

505

NOTE This table is for general use: individual product standards may include different requirements including different categories of thickness. Local coating mass and mean coating mass requirements are set out in this table for reference in such cases of dispute.

(5) Sequence of Cable Tray Installation Works:

(A) Installation of Cable Tray:

(i) Shifting of Cable Tray on Site

  • Cable Tray shall be carefully unloaded or shifted to the site by using Crane/Hydra or by sufficient manpower and moved to a defined installation location.
  • Remove the packing and ensure that the Cable Tray is free from transportation damages
  • Check and ensure that approved drawings, the correct size and type of cable trays, trunking & accessories are ready for installation.
  • Ensure that cable trays/trunking and accessories received from site store for the installation are free of rusty parts and damages.

 (ii) Marking the Route:

  • Mark the route of Cable Tray and Trunking as per approved drawings with marking threads. The route of Cable Tray and Trunking need to be coordinated with other services and shall be confirmed by the Site Engineer.
  • Minimum space from the building structure and other services to be maintained (200 mm from the nearest point) to facilitate easy handling and maintenance of cables.
  • If Possible, Do not install Cable trays below water/sewage pipes.

(iii) Hanging Support:

  • The location of hangers and supports should be carefully marked as per the approved specifications and Drawings.
  • Required sizes of holes should be marked and drilled by using a drilling machine.
  • The threaded rod (M12 steel) or Specified rod should be fixed carefully into the anchor using clamping tools for a balance smooth twist. The threaded rod should be necessary thickness and length. Sizes should be as approved in the drawing. It should be done in such a way as to avoid damage to the threaded rod.
  • When thread is done, a washer should be inserted into it. The washer should also be the required size and of quality. It should be fixed properly and the nut fastened tight to ensure that the threaded rod is strong and able to bare load.
  • Trays and ladders shall be securely anchored to supports. They shall be secured such that the tray or ladder system will not move during cable installation.
  • Ensure that rod is properly vertical under operating conditions.
  • Tighten hanger load nut securely to ensure proper hanger performance. Tighten upper nut after adjustment
  • The distance between supports is called SPAN. The support span should not be greater than the length of the tray. This will prevent two connecting points from being located within one support span.
  • The support span should not be greater than the straight section length, or as recommended by the manufacturer, to ensure that no more than one splice is located between supports.

  • Cable Tray and Trunking joints are to be positioned as close to the supports as possible, not more than 300 mm from either side.
  • Splice joints fall between the support and the quarter point. When installing a 12-foot long section, for example, a support spacing of 3.7 m (12 foot) causes the splice joints to fall at the same position every time.

  • The maximum tray overhang past the last support should not exceed 600 mm (2 ft).
  • At every maximum of 1200 mm horizontally and 1500 vertically supports should be installed.
  • Horizontal cable trays and ladders shall be supported by either wall mounted support bracket or a hanger rod system. The intervals between supports shall be as recommended by the manufacturer but this shall not exceed 1 meter for wall mounted support brackets, and 2 meter for the hanger rod system.
  • The hanger, hanging support, cable tray bracket and the ladder should be trimmed to required size and galvanizing paint should be applied on the edges.
  • Group parallel runs of trunking should be supported together where it is possible.

  • For shaft cable trays and ladders that are vertical, all supports and fixings should be done as approved.
  • Do not cut or drill structural building members (e.g., I-beams) without approval by the Main contractor.
  • Warning: Do not use a cable tray as a walkway, ladder, or support for people; cable tray is a mechanical support system for cables and raceways. Using cable trays as walkways can cause personal injury and can damage cable tray and installed cables.
  • Horizon Fitting Support: NEMA Standard
  • Supports for horizontal fittings should be located at a distance, no greater than 610 mm (24″) from each end of the fitting on the attached ladder.
  • Fitting must also be supported at the radius center point on both sides of the fitting as per below:
  • At the midpoint (45°) of the arc for a 90° elbow.
  • At the midpoint (30°) of the arc for a 60° elbow.
  • At the midpoint (22.5°) of the arc for a 45° elbow, excluded are 305 mm (12″) radius fittings.
  • At the midpoint (15°) of the arc for a 30° elbow, excluded are 305 mm (12″) radius fittings.

Method for Installation of HVAC System (Part-4)


HVAC Refrigerant  Pipe Testing:

(A) Refrigerant Piping (Leak Check) by Pressure Testing:

  •  Pressure testing helps ensure a leak free system, a critical component to a successful installation.
  • Max PSI and duration of pressure tests can vary between manufacturers and should be reviewed in the installation manual.
  • All VRV systems should be pressure tested to 550 PSIG and held for 24 hours.
  • Pressure testing process: Tighten down stop valves before any pressure testing to prevent nitrogen
  • From leaking back through condenser and contaminating refrigerant.
  • Pressure testing shall be done in three (3) steps.
  • Step 1 – Leak check 3 minutes at 150 PSI
  • Step 2 – Leak check after 5 minutes at 325 PSI
  • Step 3 – Leak check after 24 hours at 550 PSI (450 psi for systems with vertical Air Handlers)
  • After the gauge reading reaches 550 psig, isolate the system by first closing the gauge manifold, then close the nitrogen cylinder valve.
  • Check the flared and brazed connec­tions for leaks by applying a bubble solution to all joints.
  • The bubble solution must be a solution designed for refrigerant leak testing. Common soap solution must never be used on refrigerant piping as those contain chemicals that could corrode copper and brass, and cause product malfunction.
  • If the pressure does NOT drop for 24 hours, the system passes the test.
  • In this case, the pressure drop of 9.5 psig was due to temperature differences, therefore, there is no leak in the refrigerant piping system.
  • If the pressure drops and it is not due to ambient conditions, there is a leak and it must be found. Remove the bubble solution with a clean cloth, repair the leak(s), and perform the leak / pressure check again.
  • After the system has been thoroughly tested and no leaks are found, depressurize by loosening the charging hose connector at the nitro­gen cylinder regulator. When system pressure returns to normal, completely disconnect the charging hose from the cylinder, and release the nitrogen charge from all refrigerant piping. Wipe off any remaining bubble solution with a clean cloth.
  • Ambient Conditions and the Leak / Pressure Check
  • If the ambient temperature changed between the times when pressure was applied and when the pressure drop was checked, adjust results by factoring in approximately 0.79 psi for each 1°F / 1°C of temperature difference.
  • Correction formula: (°F / °C Temperature when pressure was applied – °F / °C Temperature when pressure drop was checked) x 0.79.
  • Example: When pressure (550 psig) was applied, temperature was 80°F / °C; 24 hours later when pressure drop (540 psig) was checked, temperature was 68°F / °C.
  • Thus, (80°F / °C – 68°F / °C) x 0.79 = 9.5 psig.

(B) Triple Evacuation (Vacuum)

  •  Why is a triple evacuation so important instead of a deep vacuum? Because the relationship between pressure and temperature with water.
  • When the first vacuum is pulled, some of the moisture in the lines boils and evaporates.
  • However, once it reaches a certain pressure the water will actually freeze and leave small ice crystals in the system. This is why a single deep vacuum is insufficient.
  • A triple evacuation of all piping should be performed to eliminate moisture in the system:
  • Do NOT open service valves until the deep vacuum of 500 microns or below has been achieved and the additional charge has been added
  • If Heat Recovery System connect to all three main refrigeration stop valves at outdoor unit.
  • Verify that the micron gauge is connected at a point where it can read the system’s pressure at all times during this process, even when the vacuum pump is not running during the hold test.
  • Evacuation procedures: Evacuation procedures shall be performed as follows:
  • Step 1- Operate the vacuum pump and evacuate the system to the 2,000 micron level.
  • Isolate the pump by closing the manifold gauges and the vacuum pump valve, and then watch the micron level. Micron level may rise a bit, but MUST eventually stop rising for fifteen (15) minutes.
  • If the micron level DOES NOT stop rising, there is a leak, and the leak test must be performed again. If the micron level DOES rise above 2,000 micron, re-open the manifold gauges and the vacuum pump valve and continue evacuation back down to 2,000 micron level.
  • If the micron level holds at 2,000 micron, Break the vacuum with dry nitrogen to a pressure of 2-3 PSI and hold for 15 minutes (this is to “sweep” moisture from piping).
  • Step 2- Evacuate to 1,000 micron level.
  • Isolate the pump by closing the manifold gauges and the vacuum pump valve, and then watch the micron level. Micron level may rise a bit, but MUST eventually stop rising for fifteen (15) minutes.
  • If the micron level DOES NOT stop rising, there is a leak, and the leak test must be performed again.
  • If the micron level DOES rise above 1,000 micron, re-open the manifold gauges and the vacuum pump valve, and continue evacuation back down to 1,000 micron level. If the micron level holds at 1,000 micron, Break the vacuum with dry nitrogen to a pressure of 2-3 PSI and hold for 15 minutes (this is to “sweep” moisture from piping).
  • Step3- Evacuate to static micron level ≤500.
  • Micron level must remain ≤500 for 24 hours. If the vacuum gauge rises and stops, the system may contain moisture, therefore, it will be necessary to repeat the steps of vacuum break and drying.
  • After maintaining the system in vacuum for 24 hours, check if the vacuum gauge rises or not. If it doesn’t rise, then the system is properly evacuated.
  • Close manifold gauges.
  • Shut the valve before turning off the vacuum pump.

Refrigerant Charging:

  • Weigh in additional refrigerant with digital scales. Calculate charge based on total line length plus lb/ft of diameter. Check with each unit model for correct multiplier.
  • After the amount of refrigerant to be added is determined write it down on the label on the back side of the front cover. After the vacuum/drying is complete, charge the additional refrigerant in its liquid state through the liquid stop valve service port.
  • Make sure to use installation tools you exclusively use on R410A installations to withstand the pressure and to prevent foreign material from mixing into the system.

Gas Pressure For any Ton Capacity

Refrigerant Suction Pressure (PSI) Discharge Pressure (PSI) Standing Pressure (PSI)
M/C ON M/C ON M/C OFF
R 22 60 To 70 250To 300 156
R 32 120 490 260
R 134A 35 158 To 199 95
R 290 65 275 To 300 125
R 404A 87 270 To 356 190
R 407C 63 247 To 307 153
R 410A 110 To 120 400 To 500 250
R 417A 65 261 140

Refrigerant Piping –Additional Refrigerant Charge:

  • Do NOT open unit service valves until additional refrigerant charge has been calculated, added and recorded.
  • Calculates the additional refrigerant charge based on the refrigerant piping layout. If at any time there is a change in the actual piping installation from the design layout, it must be reported back to the designer for verification.
  • Enter additional refrigerant charge amount -R410A.Lbs.
  • Record additional charge amount inside the outdoor unit using a permanent marker.

Additional Refrigerant Charged Volume

Liquid pipe Size R410A (kg/m)
6.4 mm 0.022
9.5 mm 0.057
12.7 mm 0.11
15.9 mm 0.18
19.1 mm 0.26
22.2 mm 0.37
25.4 mm 0.45

Split AC Copper Pipe Additional Refrigerant Charge

Total Pipe Length 50 Meter 60 Meter 70 Meter
Additional Refrigerant None 250 gm (25gm/Meter) 500 gm (25gm/Meter)

Electrical Connections:

  • Make all electrical connections in accordance with electrical codes and ordinances.
  • Multi-pole circuit breaker or disconnect is required to fully isolate the unit from all power.
  • Install circuit breakers/disconnects in accordance with local and national codes.
  • Select the power cable in accordance with relevant local and national regulations.
  • Unbalanced power must be maintained within 10% of supply rating among all indoor units or the unit will stop and an error code will be generated. (Significantly unbalanced power may shorten the life of the system.)
  • Ground the unit at an exclusive grounding terminal, at the electrical panel
  • The communication cable between single-phase outdoor units and between indoor and outdoor units has no polarity.

Testing of the System:

(A) Indoor Unit Cooling Measurement:

  • Measure Indoor unit Return Air Temperature or Room Temperature.
  • Measure Indoor Unit Grill Temperature.
  • Grill Temperature should be 10⁰C to 13⁰C less than Room Temperature in 10 to 15 min.

(B) Outdoor Unit Hot Air Measurement:

  • Measure Outdoor Atmosphere Air Temperature near Out Door Unit (Fan inlet Temperature).
  • Measure Outdoor Unit Fan Discharge Temperature.
  • Outdoor Unit Fan Discharge Temperature should be 11⁰C to 14⁰C higher Out Door Unit Fan inlet Temperature.

(C) Measure Suction Pressure and Discharge Press of System

  • Suction and Discharge Pressure should be according to Refrigerant Type.

(D)Measure Cuurent drawn by Compressor.

  • Ampere drawn by should be as per Manufacture recommended Current Rating.

(E) Fell Cooling of Discharge Line (Liquid Line)

  • Discharge line should be cool enough after starting of Compressor.

(F) System Cooling Problems

  1. Less or No cooling even though No Leakage in Refrigerant Pipe & Suction Pressure is OK.
  • Low Discharge Pressure
  • Weak Compressor.
  1. Ice accumulation on Discharge Line (Liquid Line / Small Line)
  • Less Gas Pressure
  • Capillary Problem.
  1. Ice accumulation on Suction Line (Gas Line / Big Line)
  • Less Gas Pressure
  • Indoor Air Filter chock up, Blower Not running, indoor unit cooling coil problem.
  • Outdoor unit Fan speed is too low, Capacitor Discharge, Refrigerant Pipe Bend or punch
  1. Ice accumulation on both Suction & Discharge Line
  • Not Cut Off Compressor,
  • Electrical Contactor stuck , Electrical Contactor coil not working
  • Problem in Sensor, Thermostats.
  • Machine is continuous working 

System Problems

System Problem Discharge Line Pressure Suction Line Pressure Suction Line Temperature Compressor Amp
Over Gas Charge High High Low (Ice on Suction Pipe) High
Under Gas Charge Low Low High Low
Capillary Block Low Low High Low
Less Air Flow on Evaporator (Indoor Unit) Low Low Low Low
Less Air Flow on Condenser (Outdoor Unit) High High High High
Dirty Condenser (Outdoor Unit) High High High High
Low Ambient Temperature Low Low Low Low
High Ambient Temperature High High High High
In sufficient Compressor Low High High Low

HVAC System installation & Testing Flow Chart

Method for Installation of HVAC System (Part-3)


(C) Y Joints

  • Confirm the Y branching piping matches allowable designs from the Installation Manual

  •  Installed with single end of Y Joints always towards outdoor unit.
  • The branch joint of outdoor side must be installed horizontally.
  • The branch joint of indoor side can be installed horizontally or vertically.
  • Y Joints are supported before and after.
  • “Y” joints are the correct size and match the locations as shown on the Selection Report.
  • Maintain a minimum distance of 20″ between branching joints, headers, elbows and equipment.
  • Recommend horizontal runs to be 3 times that of the vertical when traps cannot be avoided

  • Between two branch joints ≥1m
  • Between branch joints and indoor unit ≥0.5m
  • From the inlet or outlet of branch joint, there should be straight pipe with length at least 0.5m

(D) Copper Pipe Length:

The permitted length and drop difference

Pipe length Max. pipe length <= 240 Meter
Equivalent length from the first branch to the farthest indoor unit <= 40 Meter
Drop height Drop height between indoor unit and outdoor unit <= 110 Meter
Drop height between indoor units <= 30 Meter

  • Record the actual liquid pipe length for future reference when charging additional refrigerant.

Split AC Copper Pipe Length

A.C Capacity Maximum Pipe Length Maximum Indoor & Outdoor Height Difference
0.5 Ton 15 Meter 5 Meter
0.6 Ton 15 Meter 5 Meter
0.75 Ton 15 Meter 5 Meter
1 Ton 20 Meter 10 Meter
1.5 Ton 25 Meter 10 Meter
2 Ton 25 Meter 10 Meter
2.5 Ton 30 Meter 10 Meter
3 Ton 30 Meter 20 Meter
3.5 Ton 30 Meter 20 Meter
4 Ton 30 Meter 20 Meter

(E) Drain Pipe

  • Water leakage test
  • Check leakage of water pipe After finished installation of drainage pipe, filled the pipe with water,
  • Waiting for 24 hours to check whether there’s any leakage.
  • Check leakage from the indoor unit
  • Charge water from the check hole of indoor unit to check whether the water can be exhausted smoothly or not

Size of Drain Pipe

Condensate water volume : V (L/h)=Indoor Unit (HP)x2  I.D (mm)  Thickness (mm)
V ≤ 14 Φ 25 3
14 V ≤ 88 Φ 30 3.5
88 V ≤ 175 Φ 40 4
175 V ≤ 334 Φ 50 4.5
334 V Φ 80 6
*If Slop is <1% than select next higher Size of Drain Pipe

(F) Insulation of Refrigerant Pipe & Drain Pipe

  • The slip-on method of installation is used for insulation on new refrigeration piping
  • The inside of the insulation is coated with a powdered lubricant, making it easy to slip the insulation over the pipe.
  • Small amounts of powdered lubricant may enter the open ends of pipe or tubing. This dust must be kept out of refrigeration systems. Plug the open ends of pipe before slipping on the insulation.
  • Apply insulation only when the pipes are clean, dry, and unheated or uncooled. The surface to be insulated must be free of rust.
  • Never stretch insulation when sealing the joints. It is better to compress it slightly. Use pieces of insulation that are at least as long as the section of pipe to be insulated.
  • Always use the insulation that is properly sized for the pipe it is to cover. Do not stretch it over the pipe.
  • Do not crowd insulation-covered pipes. Space pipes far enough apart to allow for the free circulation of air. Air movement is an extra safeguard against surface condensation of cold pipes, especially under hot, humid conditions.

  • All piping insulation must be properly sealed to minimize heat loss and control condensation. On cold lines, open pipe insulation joints may allow the formation of condensation, increasing the potential for or contributing to possible pipe or tubing corrosion. Seal insulation joints
  • Do not compress piping insulation at joists, studs, columns, ducts, hangers, etc. This is important because the insulation will lose thermal efficiency where it is compressed. On cold systems, surface condensation may occur where insulation is compressed
  • Apply a coating of an approved contact-type adhesive to both butt ends to be joined.

  • Before butting the ends together, allow the adhesive to set until it is dry to the touch but still tacky under slight pressure. Join the surfaces.
  • Cut open the inside wall of the elbow, taking care not to damage the opposite wall. The slit-open elbow should slip over the fitting. Apply adhesive to the seam (not to the butt ends), allow to tack dry, and fit over the fitting. Press the seams together working from the ends toward the center of the elbow.

  • Finally, wet seal the butt ends to the incoming lengths of insulation. Cut the incoming lengths so that the butt joints are in slight compression.

  • Do not wrap the gas and liquid refrigerant pipes together.
  • Avoid compressing the insulation as much as possible
  • Be sure there are no cracks or deformities in the insulation at bends in pipes.
  • If necessary double the insulation to prevent condensation from forming in warm or humid areas.
  • Cut off excess insulation.

 Referent Pipe Insulation

Pipe Pipe size Insulation Type (EPDM or NBR)

 

Standard conditions 86°F (30°C), < 85% High humidity conditions(a)
86°F (30°C), >85%
Liquid Pipe 1/4″ (6.35 mm)  To 3/8″ (9.52 mm) 3/8″ (9 mm) 3/8″ (9 mm)
1/2″ (12.70 mm)  To  2″ (50.80 mm) 1/2″ (13 mm) 1/2″ (13 mm)
Vapor Pipe 1/4″ (6.35 mm) To 7/8″ (22.23)  1/2″ (13 mm) 3/4″ (19 mm)
  • Wrap insulation around the entire surface of each pipe, including the refrigerant pipes from the indoor unit to the service valves inside the outdoor unit, the branch joints, distribution header, and connection points on each pipe.

  • Do not wrap the vapor and liquid refrigerant pipes together.
  • If vapor and liquid pipes are in contact with one another, use thicker insulation and make sure the pipes are not pressing tightly against one another.
  • Pipe connections between the indoor unit and EEV kit: Leave 3/8 in. (10 mm) of space between vapor and liquid pipes.
  • Be sure there are no cracks or deformities in the insulation at bends in pipes or where hangers are attached to pipes.
  • If necessary, double the insulation to prevent condensation from forming in warm or humid areas.

Insulation Thickness

Refrigerant Pipe Insulation Drain Pipe Insulation
22.22mm To 28.58mm 19mm 25mm / 32mm /40mm 6mm
12.7mm To 19.05mm 13mm / 19mm
6.35mm To 9.2mm 9mm / 13mm

Method for Installation of HVAC System (Part-2)


Indoor Unit Installation:

(a) High Wall Unit:

  • The installation of the split air conditioners is a crucial job. If the installation is done accurately  air conditioner will give optimum cooling, but if it is not done properly we won’t get the desired cooling effect. A poor installations also leads to frequent maintenance problems.
  • Several factors have to consider during the installation of split air conditioner.
  • Strength of wall to hold the AC
  • The indoor unit of split AC must be installed on a wall strong enough to hold the unit’s weight.
  • Proper spacing between wall and AC unit
  • The indoor unit of split AC requires at least 15 cm of open space surrounding its top and sides for proper air flow.
  • Appropriate installation height from ground
  • Mount the indoor unit of split AC at a height of 7 to 8 feet above the ground for adequate cooling inside the room
  • Correct tilt angle of indoor unit
  • While fixing the aluminum bracket on wall make sure that the bracket is given a slight tilt angle, so that the indoor unit of split AC, when fitted is also at a slight angle to enable unrestricted flow of the condensed water from the drain pipe.

(b) Cassate Type:

  • Air inlet and outlet should be clear of obstructions, ensuring proper airflow throughout the room.
  • Condensate can be easily and safely drained.
  • A structure strong enough to withstand four 4 times the full weight and vibration of the unit.
  • Filter can be easily accessed for cleaning.
  • Leave enough free space to allow access for routine maintenance.
  • Do not install in a laundry room or by a swimming pool due to chemical sorrowing cassette coil.

  • Indoor Unit Hanger Mounting Depending on the type of ceiling, attach the threaded hanger bolts securely to the support stud. Before lifting the indoor unit to the installation location, insert the upper nuts, flat washers (with insulation), flat washers (without insulation), lower nuts and double locking nuts on the threaded hanger bolts.
  • Lift the Ceiling Cassette main body to the threaded hanger bolts. Insert the unit mounting brackets between washers and then fasten it securely.
  • Pack the indoor unit with plastic bag after hoisting to protect them from dust entering.

Louvers:.

  • Allow for ventilation intake and exhaust air based on maximum outdoor unit fan capacity.
  • Select the size, type and orientation of architectural louvers with adequate “net free area” face velocity to ensure the total external static pressure from the outdoor unit fan does not exceed design limitations.
  • No obstructions must be placed in front of the louver that could hamper the free flow (throw) of air.
  • Roof top openings and / or discharge and supply louvers must be equipped with screens to prevent bird and insect infiltration.
  • Louver Angle is not more than 15 Deg Horizontally
  • Space between Louvers is not more than 4 inch
  • If louver open rate is too small it will create noise from louver blade vibrations. Insufficient air flow exchange creates drop in outdoor unit performance and may create air conditioner stop operating.

Refrigerant & Drain Pipe Installation Work:

(a) Pipe Support:

  • A properly installed pipe system will have sufficient supports to avoid pipes from sagging during the life of the system.
  • Sag­ging pipes become oil traps that lead to equipment malfunction.
  • Pipe supports must never touch the pipe wall; supports shall be installed outside (around) the primary pipe insulation jacket. Insulate the pipe first because pipe supports shall be in­stalled outside (around) the primary pipe insulation jacket.
  • Field provided pipe supports must be designed to meet local codes. If allowed by code, use fiber straps or split-ring hangers suspended from the ceiling on all-thread rods (fiber straps or split ring hangers can be used as long as they do not compress the pipe insulation). Place a second layer of insulation over the pipe insulation jacket to prevent chafing and compression of the primary insulation in the confines of the support clamp.
  • As necessary, place supports closer for segments where potential sagging could occur. Maximum spacing of pipe supports shall meet local codes. If local codes do not specify pipe support spacing, pipe shall be supported:
  • Wherever the pipe changes direction, place a hanger within twelve 12 inches on one side and within twelve 12 to 19 inches of the bend on the other side. Support piping at indoor units, Y-branch, and Header fittings
  • Supports must be strong enough. The supports should be full thread booms, and their diameters should be ≥ 10mm.
  • Dual nuts should be adopted to fix the indoor unit under the ceiling.
The distance between the supports of the copper pipes.
Diameter Distance (m)
 ≤ 20 mm 1 Meter
20 To 40 mm 1.5 Meter
 ≥ 40 mm 2 Meter

(b) Cutting & Welding of Refrigerant Pipe:

  • Install piping to be as short and direct as possible, with a minimum number of joints, elbows and fittings. Piping must be installed parallel to the building lines..
  • Pipes must be cut accurately to measurements established on site and must be worked into place without springing or forcing.
  • Pipes must be installed as permit free expansion and contraction without damage to joins or hangers.
  • All piping shall be installed in accordance with the mechanical design. Any deviation shall be submitted for prior approval to the mechanical engineer prior to installation.
  • Refrigerant piping diameter, thickness, and temper is selected according to length, as specified in this section.
  • Cut or extend field-supplied piping as needed. To extend pipes, braze or using flared pipe connections Refer to “Pipe Cutting,” “Nitrogen Flushing While Brazing,” and “Flared Pipe Connections,”
  • Make sure that pipes are free of dirt, debris, and moisture, and do not leak.
  • Braze or use flared pipe connections to install piping. Refer to “Connecting Piping to the Single- Phase Outdoor Unit,”
  • Pipe Cutting
  • Using a pipe cutter, cut the pipe so that the cut edge is at 90° to the side of the pipe.
  • Use a reamer to remove all burrs at the cut edge. Examples of correctly and incorrectly cut pipes.

  • Selected copper tube must be of suitable wall thickness for higher operation pressures.
  • Use a tubing cutter, do not use a saw to cut pipe. De-bur and clean all cuts before assembly
  • Brazing:
  • While brazing refrigerant pipes, flush them with nitrogen gas. Use a pressure regulator to maintain a flow rate of 1.76 ft3/h (0.05 m3/h) or more.
  • Dry Nitrogen: Dry nitrogen must be used during all brazing (pressure regulated to 3 PSI) to prevent copper plate or oxidation formation.
  • Always use a non-oxidizing material for brazing. Do not use flux, soft solder, or anti-oxidant agents. If the proper material is not used, oxidized film may accumulate and clog or damage the compressors. Flux can harm the copper piping or refrigerant oil.
  • Requirement of welding:
  • When welding the copper pipe, nitrogen is necessary to protect the copper pipe.The pressure of the nitrogen is 0.02 MPa
  • Charge the nitrogen to the copper pipe at the beginning of welding and only.when the copper is fully cooled down, the nitrogen can be removed
  • If Nitrogen is not used, Welding will create Oxide on copper pipe inside and outside, which cannot be removed and it jams the refrigerant flow and damage the Compressor.

  • Warning:
  • Do not braze in an enclosed location. Do not allow the refrigerant to leak during brazing. Always test for gas leaks before and after brazing.
  • Do not allow the refrigerant to leak during brazing; if the refrigerant combusts, it generates a toxic gas. There is risk of fire, explosion, and physical injury or death.
  • Flaring: Flared tube ends should have a smooth, even round flare of sufficient length to fully engage the mating surface of the flare nut, without protruding into the threads.
  • Use a flaring tool specifically designed for flare joints in R-410A systems, which creates deeper flares than those by made by traditional flaring tools. This flaring tool has an eccentric mandrel and clutch type handle. Follow the flare tool manufacturer’s directions for using the tool.
  • Slide the flare nut over the pipe to be flared. Slide the end of the pipe into the hole on the flaring bar that fits the pipe, leaving a length of pipe, determined by tool type (see table), extending above the flaring bar. Clamp it down.
  • Remove the pipe. The end of the pipe that you flared should look like the end of a trumpet. See examples of correctly and incorrectly flared pipes.

Method for Installation of HVAC System (Part-1)


Purpose:

  • This method explains the Procedures or sequence of activity for safely and efficiently installation and Testing of Refrigerant Pipes , Drain Pipes ,Indoor and Out Door Unit of HVAC System as per standard Practice and Code.

General Equipment & Tools:

  • The equipment that will be engaged for Installation of Cable works will be
  • Lifting crane , Transportation vehicle, Fork Lift
  • Winches, Pulling Rope , Welding machine
  • Lubricant (Soap based, wax based), Cleaning agent (CRP)
  • Copper pipe Flaring tools
  • Vacuum Pump,
  • Brazing Torch , Brazing Rod , Oxy-Acetylene Brazing Kit ,Wire Brush
  • Nitrogen Cylinders , Soldering Tools
  • Crimping tool, Drilling Machine with various Bits , Grinding Machine , Cutting Machine
  • Electrical Tool Box, Cable Cutter, Screwdriver, Pliers, Spanner.
  • Ladder , Scaffolding / Mobile scaffold
  • Nylon rope, Marker , Leveling device , Tape measure
  • Removable Barricades , Portable Lights
  • Testing Equipment for System
  • Multi meter ,Clamp Meter
  • Refrigerant / Nitrogen cylinder,
  • Vacuum Gauge

Storage & Material Handling:

  • The storage area must be free from dust and Water leakages / seepages.
  • Manufacturer recommendation shall always be followed in loading/unloading and storing of Material.
  • Material and its accessories shall be unloaded handle with care in designated area of the Store (Do not directly drop to Ground) to avoid any damages.
  • Materials shall be stored in a dry place which is free from water or from weather effects and protection should be given to the material by means of covering the material with Tarpaulin sheet.
  • The Material will be stacked / unload in the site store on a proper stand on wooden loft on a flat surface at a sufficient height from Ground.
  • The A/C Units should be kept on the wooden platform and covering with polythene to protected from any dust or mechanical damages
  • For storing the copper pipes:
  • If pipes will be used soon, nozzle should be sealed by plastic bag or tape.
  • If pipes will be stored for a long time, the pipes should be charged into 0.2 to 0.5MPa Nitrogen and the nozzle should be sealed by welding.

Inspection of Materials:

  • Check The Material according to its Type, Size, Make
  • Physical Damages Inspection:
  • Damage on Pipes and Units.
  • Damage on insulation of Cable
  • In case of any damages observed during inspection, the Material shall be returned to the supplier for replacement.

 Installation of Outdoor Units :

 (a) Transporting / Lifting the Outdoor Unit

  • Use appropriate moving equipment to transport outdoor Unit, ensure the equipment is capable of supporting the weights. When lifting the unit, use lifting straps and place around the unit.
  • Always lift the unit using appropriate size of lifting straps rated to carry the unit weight and long enough to maintain a maximum of a 40° angle as shown.
  • When moving / adjusting the placement of the outdoor unit, always hold the unit by the corners. Moving the outdoor unit using the side intake holes on the frame may damage the frame.
  • Consider the unit’s center of gravity before lifting. Hoist the unit with the center of gravity centered among the lifting straps. There is a risk of the product falling and causing physical injury.
  • Lift the outdoor unit from the base at specified locations. Support the outdoor unit at a minimum of six points to avoid slippage from the rigging apparatus.
  • Do not lay the unit on its side and do not slant the unit more than 30 degrees.

  • On a supporting structure that can bear the weight of the outdoor unit. The supporting structure can be a base on the ground, on a waterproof roof, or in a pit. With sufficient clearances around the unit for service and repairs. In a well-ventilated location. Away from strong wind.
  • Away from direct exposure to rain or snow. Where there is no risk of flammable vapor leakage. Where there is no exposure to salt, machine oil, sulfide gas, or corrosive environmental conditions.

(b) Selecting the Best Location for the Outdoor Unit(s)

  • Don’ts:
  • Do not install the unit in an area where combustible gas may generate, flow, stagnate, or leak. These conditions can cause a fire.
  • Do not install the unit in a location where acidic solution and spray (sulfur) are often used or in environments where oil, steam, or sulfuric gas are present.
  • A location that allows for optimum air flow and is easily accessible for inspection, maintenance, and Where piping between the outdoor unit and indoor unit(s) / heat recovery units are within allowable Limits.
  • Avoid placing the outdoor unit in a low-lying area where water could accumulate.
  • If the outdoor unit is installed in a highly humid environment (near an ocean, lake, etc.), ensure that the site is well-ventilated and has a lot of natural light (Example: Install on a rooftop).
  • Where operating sound from the unit will disturb inhabitants of surrounding buildings.
  • Where the unit will be exposed to direct, strong winds.
  • Where the discharge of one outdoor unit will blow into the inlet side of an adjacent unit (when installing multiple outdoor units).

  • If the outdoor unit is not placed on a roof, place it on the leeward side of the building or in a location where the unit will not be ex­posed to constant wind.
  • If placement exposes the unit to constant wind activity, construct a wind break in front of the unit. Follow the placement guidelines set

  • Avoid installing the outdoor unit where it would be directly exposed to ocean winds.
  • Install the outdoor unit on the side of the building opposite from direct ocean winds.
  • Select a location with good drainage and periodically clean dust or salt particles off of the heat exchanger with water.
  • Ocean winds may cause corrosion, particularly on the condenser and evaporator fins, which, in turn could cause product malfunction or inefficient performance.
  • If the outdoor unit must be placed in a location where it would be subjected to direct ocean winds, install a concrete windbreaker strong enough to block any winds. Windbreaker height and width must be more than 150% of the outdoor unit, and be installed at least 27.5 inches away from the outdoor unit to allow for airflow.

  • Rubber anti-vibration pads are necessary to avoid vibration.

  • Foundation can be made of channel steel or concrete.

  • Reserve the space for discharging condensate water from outdoor units.
  • The outdoor unit should be placed neatly, and reserve enough space for maintenance.
  • The outdoor unit should be installed in the place that is dry, well-ventilation and close to the indoor units.

Method for Installation of Cable & Wire (Part-2)


(A) Cable Laying in Excavated Ground:

(a) Formation of Cable Trench.

  • Check the area of excavation by referring As Built drawing to find out crossing of any underground Services i.e. Gas Line, Water Line or other Cable. Check the indication marks, signs, manholes nearby area and find out the path of old services.
  • If there are structures adjacent to the work area, proper temporary supports shall be provided to the adjacent structure prior to start excavation.
  • Excavation near the existing electrical cables, instrumentation and control cables, sewer line, gas lines and any other service line shall take all necessary precautions to protect the services with proper supports & covers.
  • Ensure the working area at any confined space is free from any Hazardous Gas by proper Gas testing using the Gas testing instrument.
  • Required sign boards such as “DEEP EXCAVATION” “MEN WORKING”, “DANGER” and warning boards will be placed to indicate the excavation work. The area of excavation will be cordoned by using safety barricading to stop trespassers.
  • In open areas the excavation shall be carried out by using the machineries.
  • If the excavation level is below the local water table level suitable dewatering system shall be designed and installed in such a way that alterations and extensions to the system during operations are possible.
  • The width of the excavated Cable trench shall be as per specification or as per approved Drawings.
  • The trench shall be excavated up to the required depth of 0.76 Meter from the existing ground level or as per Specification or as per approved Drawing.
  • The Cable trench shall be kept dry during cable installation operation. The contractor shall deal with the dispose of water so as to prevent any risk to the cables and other materials.
  • Debris, rocks and unusable materials shall be removed from Excavated Trench on daily basis and it will dump at the approved dumping Location of from the site.

(b) First Layer of Sand:

  • The bottom of the trench shall be backfilled with a layer of clean and fine sand bedding of 100mm thickness or as per the approved Drawing.
  • The fill material shall be tamped. Any hard material which could damage the cable will be removed
  • Inspection of sand bed will be carried out prior to commencement of cable pulling.

(c) Cable Laying:

  • Cables are laid over the clean and fine First Layer of sand bedding.
  • Rollers must be used where cables are installed in an open trench using a pulling rope and eye; cable rollers are to be used at frequent intervals to support the cables and must never be more than 3 meters apart.
  • Care must be taken to ensure that the cable does not enter or leave the rollers at an angle that exceeds the bending radius of the cable.
  • The Pulling rope must be attached to the cable by a stocking grip with pulling eye.
  • The cable shall be drawn into the trench manually, before the pull commences, to prevent the winch to move along with the cable.
  • The cable shall be drawn into the trench smoothly with a minimum of stops and at an average speed of between 9 to 12 meters per minute, to avoid irregular movement.
  • Cables shall be arranged properly to minimize crossovers, twists.
  • All Cable shall be laying parallel to each other and cable dressing should be done properly
  • Cable identification tags shall be installed on both end of cable after the cable pulling.

(d) Second Layer of Sand:

  • The cables shall be backfilled with approved clean and fine Sand / backfill Material of 100mm thickness or as per the approved Drawing.
  • The fill material shall be tamped. Any hard material which could damage the cable will be removed
  • Inspection of sand bed will be carried out prior to commencement of Cable Protection layer.

(e) Cable Protection:

  • Cable protection tiles / Bricks / Warning Taps are laid above the second layer of dune sand filling.

(f) Back Filling:

  • Backfilling materials shall be free from stones or rocks (larger than 50 mm), fossil content, vegetation and its roots, waste materials, Material containing gypsum or other soluble salts greater than the allowable limits which might prevent proper compaction or cause to inadequately of performance.
  • Backfilling area shall be backfilled with approved material compacted in layers by suitable equipment like plate compactors, vibratory roller compactors, etc., until the specified density has been obtained.
  • Sufficient Water is poured to match the required Moisture content.
  • Intermediate cable markers to be firmly attached to the cables.
  • The thickness of fill material shall not exceed 150 mm where manual compaction methods are adopted.

(B) Cable Laying in Cable Tray / Trunking:

  • Before laying of Cable , Cable Tray work should be completed form the one end to other end of the Cable route
  • The cable tray must be cleaned and free from any dust or water dampness, before pulling the cables.
  • Use cable rollers in cable trays to avoid damage on cables during the pulling process.
  • From cable reel to cable tray, the cable is fed from the top of the reel to maintain required curvature. Sheaves, or a shoe, may be used to guide the cable into the tray.

  • Cable rollers shall be placed at every 6-12 meters or less if required to avoid touching of the cable to tray.
  • Cable laying will generally start from one end of the route length from other suitable point if required.
  • The number and size of cables drawn in to a particular cable tray shall not be exceed that allowed in specifications.
  • At any time of Cable laying only one cable should be laid on cable tray, after laying first cable necessary dressing and cable tie should be fixed than after that second cable should be lay.
  • Cut the cables to required length at both ends, seal the ends with adhesive insulation tape roll and keep in the box or enclosures to ensure no damage can occur to cables.
  • Cables shall be arranged properly to minimize crossovers, twists
  • Control cables will be laid along the LV cables. HV cables to be laid in separate trays
  • All control cables will be installed at a minimum distance of 100mm from power cables unless otherwise agreed with consultant as per site conditions.
  • After completion of all cables in the same route the cables shall be dressed and clamped.
  • All cables in horizontal or vertical runs will be secured to the trays by nylon fasteners / ties.
  • Cable identification tags as per specifications shall be installed on both end (at sending and receiving ends) of cable after the cable pulling.

(C) Cable Laying in the Building

  •  In case of Cable lay inside the buildings, the drums will be placed outside the buildings and the cable pulled in the opposite direction. After reaching the other end the length of the cable required for reaching the location inside the building will be measured and then cut the cable.
  • The cable is fed from the cable reel directly into the conduit at floor level.
  • The cable is fed from the bottom of the reel so that its curvature is continuous with no reversed bends.

  • Do not pull cable directly across short, sharp angles. After pulling completely out of one side of the enclosure, feed cable into the other side of the enclosure and pull that segment
  • Unloading equipment should not come in contact with the cable or its protective covering.

(7) Wires Pulling in Conduit:

  • Proper marking / selection of location on site to be done prior to commencement of installation works.
  • Complete a mockup installation before main works and get its approval.
  • Make sure that all conduits and boxes in both ends are free from damages and blockages etc and installation is approved.
  • Blockage shall be checked by inserting the draw wire and checking that it reaches to the other end without any disturbance.
  • Use of Steel fish wire shall be made for drawing of wires. Wires shall be drawn with adequate care.
  • Once the conduit is not blocked the wires shall be pulled using the draw wires while ensuring no damage occurs while pulling.
  • Pulling compound or lubricant shall be used for pulling the wires where required.
  • Use soap based pulling compound for short runs i.e. less than 20 meters for semi conductive insulated wires.
  • Use wax based pulling compound for the runs greater than 20 meters for semi conductive insulated wires.
  • While pulling the wires care should be taken to not insert the pull tension greater than the manufacturer allowed limits.
  • Separate conduits shall be run for lighting and power circuits and also for telephone cables. To avoid any cross talk and extraneous interference in the telephone circuits, all telephone wiring conduits shall be run with a sufficient clearance from the power and lighting conduits.
  • All separate circuits from DB’s shall have separate neutral to the points. Common neutral between separate circuits are not permissible.
  • As far as possible wiring shall be run in conduits. All conduit wiring shall be complete with continuous earth as per I.E.R.
  • The wiring shall be carried out as specified.  ‘Power’ and ‘heating’ wiring shall be kept separate and distinct from ‘Lighting’ wiring. The wiring shall be done on the distribution system with main and branch distribution boards at convenient physical and electrical centers and consideration shall be given for neatness and good appearance.
  • The wiring shall be done in the ‘Looping System. ‘Phase’ or ‘live’ conductors shall be looped at the switch box and neutral conductor can be looped from the light fan or socket outlets.
  • 5 sq. mm PVC wires in green color are to be run continuously in conduits for continuous earthing. The earth wire should be connected to GI Switch boxes and DB boxes by tapped screws.
  • No bare or twist joints shall be made at intermediate points in the through run of cables.
  • Bare or twist joints shall be carried out with due care and preferably through proper junction boxes.
  • If any joint becomes unavoidable such joints shall be made through proper cutouts or through proper junction boxes open to easy inspections.
  • Electrical Load should be balance on all the three phases for an even distribution. Before commencement of work, the contractor shall seek the approval of the Consultants / Site Engineer on the distribution of balancing of loads and circuits. The wiring shall be done by the process of looping the live conductors and the neutral wires. 
  • Color coding of wires
  • Phase : Red, Blue, Yellow,
  • Neutral: Black,
  • Earth: Green.
  • Adequate extra length shall be left at termination points. 

(8) Excess or Spare Cable Storage:

  • Store Cable reels on hard surface so that the flanges will not sink and allow reel weight to rest on cable.

(9) Cables Identification / Marking of Cables:

  • Install the tags / labels as per project specifications and as per approved material submittals.
  • Cable marking shall be positioned properly to read and identify
  • For Buried / Surface mounted cables tagging / Labeling will be corrosion resistant tags (with engraved or stamped for the identification number of the cable, voltage Rating, conductor size and make) or as per project specifications and as per approved material submittals.
  • Cables shall be identified at feeders i.e. the sending and receiving ends (outgoing cables in SMDB’s and final DB’s) about 50mm below the gland.
  • All termination shall be provided with tight fitting covering sleeves.

(10) Duct Seals:

  • After installation of all Cables, all cable ducts / Hume Pipes / Sleeves entering substations and buildings to be duct sealedto prevent the ingress of water and gas.

(11) REFERENCES

  • IEC 60228, BS 6360.
  • BS 5467.

(12) Flow Chart:

  

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