Abstract of IS: 5613 (Part 1, 2, 3)
1) Overhead Line
- Pole Foundation hole should be drilled in the ground with the use of earth-augers. However, if earth-augers are not available a dog pit of the size I.2 x O.6 m should be made in the direction of the line.
- The depth of the pit shall be in accordance-with the length of the pole to be planted in the ground as given in respective Indian Standards.
2) Tubular Pole
- Steel Tubular Poles, Rolled Steel Joists and Rails – A suitable pad of cement concrete, stone or steel shall be provided at the bottom of the pit, before the metallic pole is erected.
- Where metal works are likely to get corroded ( points where the pole emerges out of the ground ), a cement concrete muff, 20 cm above and 20 cm below the ground with sloping top shall be provided.
3) RCC Pole
- RCC poles generally have larger cross-section than the PCC poles and, therefore, the base plates
or muffing are usually not provided for these types of poles.
- However, for PCC poles, a base plate ( 40 x 40 x 7 cm concrete block ) shall be provided. Cement concrete muff with sloping top may also be provided, 20 cm above and 20 cm below-the ground level, when the ground or local conditions call for the same.
4) H.V Line (120m To 160m Span)
- The insulators should be attached to the poles directly with the help of ‘D’ type or other suitable clamps in case of vertical configuration of conductors or be attached to the cross arms with the help of pins in case of horizontal configuration
- Pin insulator:; and recommended for use on straight runs and up to maximum of 10’ deviation.
- The disc insulators are intended for use a pole positions having more than 30’ angle or for dead ending of I1 kV lines.
- For lines having=, a bend of 10” to 30’, either double cross arms or disc insulators should be used for HT lines up to 11 kV. For low and medium voltage line, shackle insulators should be used
- For Vertical configuration for Conductor erection:
- Distance between Pole’s Top to Disc insulation=200mm.
- Between Disc insulator to Disc Insulator=1000mm.
- Between Disc insulator to Guy Wire=500mm.
5) Stay Wire Angle with Pole
- Overhead lines supports at angles and terminal positions should be well stayed with stay wire, rod, etc. The angle between the pole and the wire should be about 45” and in no case should be less than 30”. If the site conditions are such that an angle or more than 30“ between the pole and the stay wire cannot be obtained, special stays such as, foot stay, flying stay or struts may be used
- Hard drawn galvanized steel wires should be used as stay wires. The tensile strength of these wires shall not be less than 70 kgf/mm2. Only standard wires should be used for staying purpose.
6) Stay Rod
- Mild steel rods should be used for stay rods. The tensile strength of these rods shall not be less than 42 kgf/mm2
7) Stay Anchor
- Stays should be anchored either by providing base plates of suitable dimensions or by providing angle iron or rail anchors of suitable dimensions and lengths.
8) Guy Insulator
- Stay wires and rods should be connected to the pole with a porcelain guy insulator. Wooden insulators should not be used. Suitable clamps should be used to coMeCt stay wires and rods to its anchor.
- For low and -medium voltage lines a porcelain guy insulator should be inserted in the stay wire at a height of 3 m vertically above the ground level. For high voltage lines, however, the stays may be directly
9) Stay Setting
- The inclination of stay relative to the ground is roughly determined before making the hole for excavation. This enables the position of the stay hole to be fixed so -that when the stay is set, the
stay rod will have the correct inclination and will come out of the ground at the correct distance from the pole. The stay rods should be securely fixed to the ground by means of a suitable anchor
10) O/H Conductor Drum
- In loading, transportation and unloading conductor drums should be protected against injury. The conductor drums should never be dropped and may be Tolled only as indicated by the arrow on the drum side. The drums should be distributed along the route at distance approximately equal to the length of the conductor wound on the drum.
11) Binding of O/H Conductor
- The insulators should be bound with the line conductors with the help of copper binding wire in case
of copper conductors, galvanized iron binding wire for galvanized iron conductors and aluminum binding wire or tape for aluminum and steel reinforced aluminum conductors ( ACSR ). The size of the binding wire shall not be ‘less than 2 mm”
12) Different Voltage on Same Support
- Where conductors forming parts of systems at different voltages are erected on the same supports.
- Adequate clearance and guarding shall be provided ~to guard against the danger to lineman and others from the lower voltage system being charged above its normal working voltage by leakage from or contact with the higher voltage system.
- The clearance between the bottom most conductor of the system placed at the top and the top most conductor of the other system should not be less than 1.2m.
- Jumpers from dead end points on one side of the pole to the dead end side on the other wide of the pole should be made with conductor of same material and current carrying capacity as that of the line conductor.
- The jumpers should be tied with the line conductor with a suitable clamp. If the material of the jumper wire is different from that of the line conductor, suitable bimetallic clamps should be used. If copper and aluminum bimetallic clamps are to be used, it should be ensured that the aluminum conductor is situated above the copper conductor so that no copper contaminated water comes in contact with aluminum.
14) Jumper Clearance
- For high voltage lines the jumpers should be so arranged that there is minimum clearance of O.3 m under maximum deflection condition due to wind between the live jumpers and other metallic parts. This may involve erection of insulators and dead weights specially for fixing the jumpers.
15) Binding of O/H Line
- Length of Binding wire on Insulator (From outer surface if Insulator to end of binding wire) should be 6D(Where D=Diameter of O/H Conductor)
16) O/H Patrolling
- All overhead lines should be patrolled periodically at intervals not exceeding 3 months from the ground when the line is live.
17) Pole Earthing
- All metal poles including reinforced cement concrete and pre-stressed cement concrete poles shall be permanently and efficiently earthed.
- For this purpose a continuous earth wire shall be provided and securely fastened to each pole and connected with earth ordinarily at 3 points in every kilometer, the spacing between the points being as nearly equidistant as possible. Alternatively each pole, and metallic fitting attached thereto shall be efficiently earthed.
18) Stay wire Earthing
- All stay wires of low and medium voltage lines other than those which are connected with earth by means of a continuous earth wire shall have an insulator inserted at a height of not less than 3 m from the ground.
19) Earthing Wire Size
- The cross-sectional area of the earth conductor Sims not be less than 16 mm2 if of copper, and 25 mm2 if of galvanization or steel.
20) Conductor Clearance
- Fixing Cross Arm in Low and Medium Voltage in Horizontal Configuration:
|Up to 650V||Horizontal “V” Shape Cross arm: (P-P(Street Light)-Neutral)||Phase to Neutral=750mm , Phase to Phase(Streetlight at Top of Pole)=325mm, Last Phase-Cross Arm end=80mm|
|650V to 11KV||Horizontal Cross arm: (P-P(Street Light)-N)||Phase-Phase=300mm, Phase-Phase(Street Ltg)=300mm, Phase-Neutral=300mm, Last Phase-Cross Arm end=80mm|
|Low and Medium Voltage Line||(Horizontal Configuration):||Less than 75cm Sag(P-P) =30 cm 76cm to 120 cm Sag (P-P)=45 cm 121cm to 145 cm Sag (P-P)=60 cm|
|Low and Medium Voltage Line||(Vertical Configuration):||Less than 70cm Sag(P-P) =20 cm 71cm to 100 cm Sag (P-P)=30 cm|
|High Voltage Line||(Horizontal Configuration):||Up to 120cm Sag(P-P) =40 cm 140cm to 225cm Sag (P-P)=65 cm Double Circuit on Same Pole at Different Level: Distance between two Circuit=120 cm|
21) O/H Conductor
- Choice of Conductors — The physical and electrical properties of different conductors shall be in accordance with relevant Indian Standards. All conductors shall have a breaking strength of not less than 350 kg.
- However, for low voltage lines with spans less than 15 m and installed either on owner’s or consumer’s premises, conductors with breaking strength of not less than 140 kg may be used.
22) Voltage Variation
- In accordance with the Indian Electricity Rules voltage variation for low voltage lines should not be more than ± 6 percent and for high voltage lines should not be more than ± 6 percent to –9 percent.
23) Span (Up to 11KV)
- Recommended Span Lengths — The recommended span lengths for lines up to 11 kV are 45, 60, 65, 75, 90, 105 and 120 meters
- There are no fixed rules for spacing arrangement of overhead line conductors. However, the following formula gives an economical spacing of conductors: D=500+18U+(L*L/50)
- Where D=Spacing between conductor(mm), U=Voltage(p-p in kv),L=Span in meter
24) Clearance (Up to 11KV)
Min height of any Overhead conductor
|Type of Crossing||Clearance|
|Across any street (Low Medium Voltage)||5.8 Meter|
|Across any street (High Voltage)||6.1 Meter|
|Along with street (Low Medium Voltage)||5.5 Meter|
|Along with street (High Voltage)||5.8 Meter|
|Line(Bare) erected elsewhere(Low &Medium Voltage)||4.6 Meter|
|Line(Bare) erected elsewhere(High Voltage)||4.6 Meter|
|Line(Insulated) erected elsewhere(Low &Medium Voltage)||4.0 Meter|
|Line(Insulated) erected elsewhere(High Voltage)||4.0 Meter|
|Line conductor from buildings(Low &Medium Voltage)||2.5 Meter|
|Line conductor from buildings(High Voltage)||3.7 Meter|
|System Voltage||Number Of Circuit||Span|
|33 KV (over Pole)||Single||90 Meter to 135 Meter|
|33 KV||Single||180 Meter to 305 Meter|
|33 KV||Double||180 Meter to 305 Meter|
|66 KV||Single||204 Meter to 305 Meter|
|66 KV||Double||240 Meter to 320 Meter|
|220 KV||Single||320 Meter to 380 Meter|
|220 KV||Double||320 Meter to 380 Meter|
26) Danger Plate(11KV To 220KV)
- Danger and number plates are located on Face (Feeding End (S/S))of pole.
27) Anti Climbing Device(11KV To 220KV)
- Leg 1 ( Right End Leg (Feeding End (S/S)) represents the leg with step bolts and anti-climb device gate if any. If two legs with step bolts are required, the next is No. 3 leg (Diagnostically opposite of Leg1)
28) Clearance (11KV to 220KV)
Number Of Circuit
P-P Vertical Clearance
P-P Horizontal Clearance
- In case triangular formation has to be adopted, the conductor lying below an upper one shall be staggered out by a distance of X=V/150 Where V=System Voltage, X=staggered distance in meters.
- The earth wire sag shall be not more than 90 percent of the corresponding sag of power conductor under still air conditions for the entire specified temperature range
|Line Voltage(KV)||Spacing between P-E|
|33 KV||1.5 Meter|
|66 KV||3.0 Meter|
|110 KV||4.5 Meter|
|132 KV||6.1 Meter|
|220 KV||8.5 Meter|
29) Earthing(11KV To 220KV)
- All metal supports and all reinforced and pre stressed cement concrete supports of overhead lines and metallic fittings attached thereto, shall be permanently and efficiently earthed.
- For this purpose a continuous earth wire shall be provided and securely fastened to each pole and connected with earth ordinarily at 3 points in every kilometer, the spacing between the points being as nearly equidistant as possible. Alternatively, each support and metallic fittings attached thereto shall be efficiently earthed.
- Each stay-wire shall be similarly earthed unless an insulator has been placed in it at a height not less than 3.0 meters from the ground
30) Tower Height (up to 400KV)
- The transmission lines and transmission line structures of height 45 m and above shall be notified to the Directorate of Flight Safety (DFS), Air Headquarters (Air HQ), New Delhi.
- For construction of any transmission line/structure or a portion thereof, falling within a radius of 20 km around the Defense aerodromes and air to firing ranges provisions of the Aircraft Act 1934, Section 9A as amplified by the associated Gazette Notification SO 988 Part II, Section 3,
- Within a radius of 10 km around aerodromes and air to ground firing ranges, all transmission lines and structures of height 45 meters or more shall be provided with day and night visual aids.
31) Line Marker (up to 400KV)
- Line Markers: Colored globules of 40-50 cm diameter made of reinforced fiber glass or any other suitable material, weighing not more than 4.5 kg each with suitable clamping arrangement and drainage holes shall be installed on the earth wire(s) in such a manner that the top of the marker is not below the level of the earth wire.
- Up to 400-metre span, one globule shall be provided in the middle of the span on the highest earth wire. In case of double earth wires, the globule may be provided on any one of them. For span greater than 400-metres, one additional globule may be provided for every additional 200-metre span or part thereof. Half orange and half white colored globule should be used.
32) Structure Marking (up to 400KV)
- Structure Marking :The structure portion excluding cross-arms above 45 m height shall be painted in alternate bands of international orange and white colors.
- The bands shall be perpendicular to the vertical axis and the top and bottom bands shall be orange. There shall be an odd number of bands. The maximum height of each band shall be 5 m.
33) Span (up to 400KV)
- Minimum ground clearance from lowest point of power conductor shall be 8840 mm.
- Minimum mid-span vertical clearance between power conductor and ground wire in still air at normal design span shall be 9000 mm.
34) Clearance (up to 400KV)
- Vertical clearances above Railway Track : 220KV To 400KV =19.3 Meter
35) Shield Angle (400KV)
- For 440KV :Shielding Angle= 20”
36) Clearance (400KV)
- For 440KV :Maximum Length of Suspension Strings from Shackle Attachment at Hanger to Center Line of Conductor =3 850 mm
- For 440KV :Maximum Length of Tension Strings from Tower Attachment to Compression Dead-End Attachment=5600mm
- For 440KV :Minimum Mid-Span Vertical Clearance Between Power Conductor end Ground Wire in Stilt Air=9000mm
- For 440KV :Right-of-way and transport requirements of maintenance, the following right-of-way width for 400 kV lines are recommended: Single/Double Circuit=50meter
- For 400KV Road Crossing: At all important crossings, the towers shall be fitted with normal suspension or tension insulator strings depending on the type of towers but the ground clearance at the roads under maximum temperature and in still air shall be such that even with conductor bundle broken in adjacent span, the ground clearance of the conductor from the road surface shall not be less than 8’84 meters.
- At all national highways tension towers shall be used. The crossing span, however, shall not exceed 25 meters in any case