Indian Standard Code-Abstract (IS:5613/IS:5039/IS:11892/IS:1455/IS:11171


Abstract of IS : 5613 for HV Line

Overhead LinePole 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.
Tublar PoleSteel 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.
RCC PoleRCC 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.
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.
H.V Line

(120m To 160m Span)

Pin insulator and recommended for use on straight runs and up to maximum of 10’ deviation.
H.V Line

(120m To 160m Span)

The disc insulators are intended for use a pole positions having more than 30’ angle or for dead ending of I1 kV lines.
H.V Line

(120m To 160m Span)

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
H.V Line

(120m To 160m Span)

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.

Stay Wire Angle with PoleOverhead 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
Stay WireHard 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.

Stay RodMild steel rods should be used for stay rods. The tensile strength of these rods shall not be less than 42 kgf/mm2
Stay AnchorStays should be anchored either by providing base plates of suitable dimensions or by providing angle iron or rail anchors of suitable dimensions and lengths.
Guy InsulatorStay 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
Stay SettingThe 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
O/H Conductor DrumIn 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.
Binding of O/H ConductorThe 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 steelinforced aluminum conductors ( ACSR ). The size of the binding wire shall not be ‘less than 2 mm”
Different Voltage on Same SupportWhere 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.
JumperJumpers 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 aluminium bimetallic clamps are to be used, it should be ensured that the aluminium
conductor is situated above the copper conductor so that no copper contaminated water comes in contact with aluminium.
Jumper ClearanceFor 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.
Binding of O/H LineLength 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)
O/H PatrollingAll overhead lines should be patrolled periodically at intervals not exceeding 3 months from the ground when the line is live.
Pole EarthingAll 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 kilometre, the spacing between the points being as nearly equidistant as possible. Alternatively each pole, and metallic fitting attached thereto shall be efficiently earthed.
Stay wire EarthingAll 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.
Earthing Wire SizeThe cross-sectional area of the earth conductor Sims not be less than 16 mm2 if of copper, and 25 mm2 if of galvanized iron or steel.
Conductor ClearanceFixing Cross Arm in Low and Medium Voltage in Horizontal Configuration:
P-P-N ClearanceUp 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
P-P-N Clearance650V 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

P-P-N ClearanceLow and Medium Voltage Line (Horizontal Configuration):                                                                                                                                 Less than 75cm Sag =P-P 30cm                                                                                                                                   76cm To 120cm Sag   =P-P 45cm                                                                                                                                     121cm To 145cm Sag  =P-P 60cm
P-P-N ClearanceLow and Medium Voltage Line (Vertical Configuration):                                                                                                                                 Less than 70m Sag =P-P 20cm                                                                                                                                   71m To 100m Sag   =P-P 30cm                                                                                                                           
P-P-N ClearanceHigh Voltage Line (Horizontal Configuration):                                                                                                                                 Up to 120m Sag =Phase to Phase= 40cm                                                                                                                                   140m To 225m Sag =Phase to Phase= 65cm                                                                                                                              
P-P-N ClearanceDouble Circuit on Same Pole at different level : Distance between Two Circuit is 120cm.
O/H ConductorChoice 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.
Voltage VariationIn 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
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
Span (Up to 11KV)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
Clearance(Up to 11KV)Min height of any conductor of an overhead line across any street (Low Medium Voltage)=5.8m
Clearance(Up to 11KV)Min height of any conductor of an overhead line across any street (High Voltage)=6.1m
Clearance(Up to 11KV)Minimum height of any conductor of an overhead line along any street(Low &Medium Voltage)=5.5m
Clearance(Up to 11KV)Minimum height of any conductor of an overhead line along any street(High Voltage)=5.8m
Clearance(Up to 11KV)Minimum height of any conductor (bare) of an overhead line erected elsewhere(Low &Medium Voltage)=4.6m
Clearance(Up to 11KV)Minimum height of any conductor (bare) of an overhead line erected elsewhere(High Voltage)=4.6m
Clearance(Up to 11KV)Minimum height of any conductor (insulated) of an overhead line erected elsewhere(Low &Medium Voltage)=4.0m
Clearance(Up to 11KV)Minimum height of any conductor (insulated) of an overhead line erected elsewhere(High Voltage)=4.0m
Clearance(Up to 11KV)Minimum clearance of overhead line conductor from buildings(Low & Medium Voltage)=2.5m
Clearance(Up to 11KV)Minimum clearance of overhead line conductor from buildings(High Voltage)=3.7m
Span(11KV To 220KV)System Voltage          Number Of Circuit          Span (Meter)                                                                                    33KV (over Pole)          Single                               90 To 135 Meter                                                                                 33KV                              Single                              180 To 305 Meter                                                                              33KV                             Double                              180 To 305 Meter                                                                             66KV                              Single                              204 To 305 Meter                                                                              66KV                             Double                              240 To 320 Meter                                                                       220KV                           Single                              320 To 380 Meter                                                                               220KV                            Double                            320 To 380 Meter
Danger Plate(11KV To 220KV)Danger and number plates are located on Face (Feeding End (S/S))of pole
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 (Dignotical opposite of Leg1)
Clearance(11KV To 220KV)Voltage                    Circuit               P-P Vertical       P-P Horizontal                                                                               33KV (over Pole)     Single               1.5 Meter          1.5 Meter                                                                  33KV                        Single/Double   1.5 Meter          1.5 Meter                                                                  66KV                        Single/Double    2.0 Meter         3.5 Meter                                      110KV                      Single/Double    3.2 Meter         5.5 Meter                                                                  220KV                      Single/Double      4.9 Meter        8.4 Meter  
Clearance(11KV To 220KV)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

Clearance(11KV To 220KV)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
Clearance(11KV To 220KV)Line Voltage(KV)         Spacing between P-E (m)                                                                                                     33KV                               1.5meter                                                                                                                                       66KV                               3.0meter                                                                                                                                     110KV                             4.5meter                                                                                                                                   132KV                              6.1meter                                                                                                                                220KV                              8.5meter
Earthing(11KV To 220KV)All metal supports and all reinforced and prestressed 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.
Earthing(11KV To 220KV)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
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.
Tower Height (up to 400KV)For construction of any transmission line/structure or a portion thereof, falling within a radius of 20 km around the Defence 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,
Tower Height (up to 400KV)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.
Line Marker   (up to 400KV)Line Markers :Colored globules of 40-50 cm diameter made of reinforced fibber 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.
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 colours. 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.
Span(up to 400KV)Minimum ground clearance from lowest point of power conductor shall be 8 840 mm.
Span(up to 400KV)Minimum mid-span vertical clearance between power conductor and ground wire in still air at normal design span shall be 9 000 mm.
Clearance  (up to 400KV)Vertical clearances above Railway Track :  220KV To 400KV =19.3 Meter
Shield Angle (400KV)For 440KV :Shielding Angle= 20°
Clearance  (400KV)For 440KV :Maximum Length of Suqeusion Strings from Shackle Attachment at Hanger to Centre Line of Conductor =3 850 mm
Clearance  (400KV)For 440KV :Maximum Length of Tension Strings from Tower Attachment to Compression Dead-End Attachment=5600mm
Clearance  (400KV)For 440KV :Minimum Ground Clearance from Lowest Point of Power Conductor=8400mm
Clearance  (400KV)For 440KV :Minimum Mid-Span Vertical Clearance Between Power Conductor end Ground Wire in Stilt Air=9000mm
Clearance  (400KV)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
Clearance  (400KV)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.

           Phase-Phase-Neutral Conductor Clearance (As per IS:5613)

Up to 650VHorizontal “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 11KVHorizontal 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


Min Overhead conductor Clearance (Up to 11KV) (As per IS:5613)

Type of CrossingClearance
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


Span of Overhead Conductor (As per IS:5613)

System VoltageNumber Of Circuit Span
33 KV (over Pole)Single90 Meter to 135 Meter
33 KVSingle180 Meter to 305 Meter
33 KVDouble180 Meter to 305 Meter
66 KVSingle204 Meter to 305 Meter
66 KVDouble240 Meter to 320 Meter
220 KVSingle320 Meter to 380 Meter
220 KVDouble320 Meter to 380 Meter


Clearance (11KV to 220KV) (As per IS:5613)
VoltageNumber Of CircuitP-P Vertical ClearanceP-P Horizontal Clearance
33KVSingle1.5 Meter1.5 Meter
33KVSingle/Double1.5 Meter1.5 Meter
66KVSingle/Double2.0 Meter3.5 Meter
110KVSingle/Double3.2 Meter5.5 Meter
220KVSingle/Double4.9 Meter8.4 Meter


Phase to Earth wire Clearance (As per IS:5613)

Line Voltage(KV)Spacing between P-E
33 KV1.5 Meter
66 KV3.0 Meter
110 KV4.5 Meter
132 KV6.1 Meter
220 KV8.5 Meter

Abstract of IS:5039 for Distribution Pillar (<1KV AC&DC)

Distribution pillarsDistribution pillars are used by a number of distributing agencies to interconnect, terminate, control, protect and sectionalize distribution feeders.
They are generally located on public footpaths abutting the building line or along the kerb line of footpaths.
The distribution pillars covered by this standard are intended to incorporate HRC type fuses/links only and of current rating not exceeding 630 amperes.
This standard covers distribution pillars for voltages not exceeding 1 000 V ac or 1 200 V dc, the current rating in each outgoing or incoming circuit not exceeding 630 A, for use on ac or dc systems, in outdoor conditions.
Rating of Individual Circuits:


The rated current of the outgoing or incoming circuits shall be as follows: 160, 200, 250, 400 and 630 amperes.
NOTE 1: These ratings correspond to those of fuse-bases.
NOTE 2 : All the incoming circuits of the same distribution pillar shall have the
Same current rating and similarly all the outgoing circuits of the same distribution pillar shall have the same current rating. Unless otherwise specified the sum of the rated current of the incoming circuits shall be fixed at the 2/3 of the sum of the current ratings of outgoing circuits, rounded up to the nearest higher value of the preferred current
Rated Diversity Factor:


The rated diversity factor of the distribution pillar having several incoming and outgoing circuits is the ratio of the maximum sum at any one time, of the assumed circuits of all the circuits involved, to the sum of the rated currents of all the circuits of the distribution pillar.

2 and 3                                                 0.9

4 and 5                                                 0.8

6 to 9 inclusive                                     0.7

10 and above                                        0.6



It shall be in all respect suitable for outdoor installations. It shall be made from a suitable material to withstand rough usage and weather. If fabricated out of MS sheets the thickness of the sheet shall be at least 3.15 mm


Distribution pillars shall have a set of double hinged doors at the front. Similar doors shall be provided at the back also; if specified.
 The doors shall be so fitted as to provide the interior with maximum protection from atmospheric conditions. The hinges shall be of such construction that the doors can be swung open by not less than 150°.
 In addition the hinged design shall permit doors being completely removed when necessary. The base horizontal member shall be completely removable to facilitate cable jointing


The top of the pillar shall be fitted with a sloping canopy design of which shall be such that rain water shall not accumulate on the top.


If required, an apron (two if there are doors at the rear also) shall be provided below the door level of the pillar. They shall be easily removable. The apron shall be made from a suitable material to withstand rough usage. If made from sheet steel, the thickness of the sheet shall be at least 3.15 mm.
Pillar Lighting:


A bayonet lamp holder complying with IS : 1258-1987, with a tumbler switch, competing with IS : 3854-1988†, a three pin plug and socket complying with IS : 1293-1988 with necessary fuses and wiring shall be provided inside the pillar.
Unless otherwise agreed between the manufacturers and user, on TPN fuse boards, terminals for the neutral conductor shall allow the connection of aluminium conductors having a current carrying capacity:
(a) equal to half the current carrying capacity of the phase conductor with a minimum of 25 mm2, if the size of the phase conductor exceeds 25 mm2
(b) equal to the full current carrying capacity of the phase conductor if the size of the latter is less than or equal to 25mm2.
Bus-barSuitable barriers shall be provided between bus-bars


The distribution pillar shall be provided with two separate earthing terminals and the framework shall be metallically connected with the casing.


Abstract of IS:11892

Maximum external Diameter of Cable (dc)==kc X d

where d= Nominal dis of conductor standards. Kc=1 for solid cable.

For stranded cable kc=3 (up to 7 stranded).

More than 7 stranded kc=1.16 X sq.root(n1),

n1=Number of stranded

Abstract of IS:1445 for Porcelain Insulator

Porcelain InsulatorType AAn insulator unit in which the lengths of the shortest puncture patch through solid insulating material is at least equal to half the length of the shortest flash over path through air outside the insulator
Type BAn insulator or an insulator unit in which the length of the shortest puncture patch through solid insulating material is less than half the length of the shortest flash over path through air outside the insulator.



Abstract of IS: 1678 for Pole

PCC PoleClass of PoleLength of PoleMin Ultimate Transverse Load
Class 117 Meter3000 Kg
Class 217 Meter2300 Kg
Class 317 Meter1800 Kg
Class 417 Meter1400 Kg
Class 516 Meter1100 Kg
Class 612.5 Meter1000 Kg
Class 712 Meter800 Kg
Class 812 Meter700 Kg
Class 911Meter450 Kg
Class 109 Meter300 Kg
Class 117.5Meter200 Kg
PCC Pole ToleranceTolerance: The tolerance of overall length of the poles shall be + 15 mm.
The tolerance on cross-sectional dimensions shall be + 3 mm.
The tolerance on cross-sectional dimensions shall be + 3 mm.
The tolerance on uprightness of the pole shall be 0.5 per cent
PCC Pole depth in Ground:


Length of PoleMin depth in ground
6 Meter To 7.5 Meter1.2 Meter
8 Meter To 9 Meter1.5 Meter
9.5 Meter To 11 Meter1.8 Meter
11.5 Meter To 13 Meter2.0 Meter
13.5 Meter To 14.5 Meter2.2 Meter
15 Meter To 16.5 Meter2.3 Meter
17 Meter2.4 Meter

Abstract of IS:11171 for Transformer

Transformer Temperature Rise Limit


Part Type of Insulation   Degree (Centigrade) 
Part=WindingType of Insulation=A50 Centigrade
Part=WindingType of Insulation=E65 Centigrade
Part=WindingType of Insulation=B70 Centigrade
Part=WindingType of Insulation=F90 Centigrade
Part=WindingType of Insulation=H115 Centigrade
Part=WindingType of Insulation=G140 Centigrade
Part= Core, MetallicPartType of Insulation=-Not rise to damage core or metallic part
Transformer Cooling Method indication


Type of cooling Medium: A=Air
First Letter= Type of Cooling Medium (Contact with Winding)
Second Letter = Kind of Circulation(Contact with Winding)
Third Letter= Type of Cooling Medium (Contact with external cooling System)
Forth Letter = Kind of Circulation (Contact with external cooling System)
Transformer Reduce Temperature Rise Limit


TRANSFORMER designed for operation at an altitude greater than 1 000 m but tested at normal altitudes  the limits of temperature rise are reduced by the following amounts for each 500 m by which the intended working altitude exceeds 1000Meter
( a) Natural-air-cooled Transformers 2.5 %

(b) Forced-air-cooled Transformers %

Transformer Parallel operation Condition


(1 )Rated power ( kVA );
(2) Rated voltage ratio;
(3) Voltage ratios corresponding to tappings other than the principal tapping.
(4) Rated power (kVA); Rated voltage ratio; Voltage ratios corresponding to tapings other than the principal tapping.
 (5) Load loss at rated current on the principal tapping, corrected to the appropriate reference temperature.
 (6) Impedance voltage at rated current ( on the principal tapping ).
(7) Short-circuit impedances, at least on the extreme tappings, if the tapping. Range of the tapped winding exceeds + or – 5 %.