1 – 4 core

LT & XLPE Cables

XLPE insulated power cable to IS 7098 — aluminium or copper, single through four core including the 3.5-core reduced-neutral construction, armoured or unarmoured, at a thousand kilometres a month.

Cores1, 3, 3.5 and 4

Output1,000 km a month

StandardIS 7098 (Part 1)

Request a quotation Download 2-page catalogue (PDF)

Cable hall

Where the chain widened.

LT cable was the second product line the business added, back when it made only poles. It is now a 1,000 kilometre a month operation, and it underpins the underground cable work we are known for in the field.

Because we lay cable as well as make it, the specification we manufacture to is the one we then have to install, joint and commission ourselves. That tends to concentrate the mind on the things that matter — insulation wall consistency, armour quality and drum handling.

General

Parameter	Specification
Product	XLPE insulated, PVC sheathed power cable
Voltage grade	1100 V (1.1 kV) grade; HT grades 3.3 kV to 33 kV to order
Conductor	Aluminium or copper, Class 2 stranded to IS 8130
Cores	1, 3, 3.5 and 4 core
Size range	Aluminium power cable from 4 sq.mm upwards; copper control cable 1.5 to 4 sq.mm
Armouring	Galvanized steel round wire or flat strip to IS 3975, or unarmoured
Outer sheath	PVC ST1 (70 °C) or ST2 (90 °C) to IS 5831
Standard	IS 7098 (Part 1) for 1.1 kV; IS 7098 (Part 2) for 3.3–33 kV; IEC 60502-1 for export
Monthly capacity	1,000 km

Electrical

Parameter	Specification
Maximum conductor temperature	90 °C continuous; 250 °C short circuit
Core identification	3-core red/yellow/blue; 4-core red/yellow/blue/black; reduced neutral black
HT screening	Extruded semiconducting conductor and insulation screens above 1.9/3.3 kV
Screen resistivity	Conductor screen ≤ 1000 Ω·m; insulation screen ≤ 500 Ω·m
Metallic screen	Non-magnetic — copper tape or wire, or aluminium

Reference data — what the standards requireTables from the Indian Standard, for checking any quotation against it

How to read a cable designation

Cable type designations under IS 7098 and IS 5831

Designation	Meaning
A2XFY	Aluminium conductor, XLPE insulated, flat steel strip armoured, PVC sheathed
A2XWY	Aluminium conductor, XLPE insulated, round steel wire armoured, PVC sheathed
A2XY	Aluminium conductor, XLPE insulated, unarmoured, PVC sheathed
2XFY / 2XWY / 2XY	As above with copper conductor
ST1 / ST2	PVC outer sheath — general purpose (70 °C) / heat resistant (90 °C)

Insulation thickness

Nominal XLPE insulation thickness, 1100 V grade — IS 7098 (Part 1)

Conductor size (sq.mm)	Single core armoured (mm)	Unarmoured / multi-core (mm)
1.5 – 16	1.0	0.7
25 – 35	1.2	0.9
50 – 70	1.4	1.1
95 – 150	1.7	1.4

Values above 150 sq.mm are confirmed against the printed standard on enquiry.

Nominal XLPE insulation thickness by voltage grade — IS 7098 (Part 2)

Voltage grade	Nominal insulation thickness (mm)
3.8 / 6.6 kV (earthed)	2.8
6.35 / 11 kV (earthed)	3.4 – 3.6
11 / 11 kV (unearthed)	5.5
12.7 / 22 kV (earthed)	6.0
19 / 33 kV (earthed)	8.8

Note the step from 3.6 mm at 11 kV earthed to 5.5 mm at 11 kV unearthed. Unearthed-grade cable costs materially more, and quoting earthed thickness against an unearthed enquiry is a common and expensive error.

Armour selection

Armour selection — IS 7098 (Part 1) and IS 1554 (Part 1)

Calculated diameter under armour	Round GI wire nominal diameter	Strip alternative
Up to 13 mm	1.40 mm	Not permitted
Above 13 up to 25 mm	1.60 mm	Flat strip
Above 25 up to 40 mm	2.00 mm	Flat strip
Above 40 up to 55 mm	2.50 mm	Flat strip
Above 55 up to 70 mm	3.15 mm	Flat strip
Above 70 mm	4.00 mm	Flat strip

Round wire is used on single-core AC cables because it can be non-magnetic and so avoids the eddy-current losses a magnetic strip would cause. Flat strip is the dominant construction for multi-core LT distribution cable in India.

PVC insulated cables — IS 1554 (Part 1)

PVC insulated heavy duty cables, 1100 V — IS 1554 (Part 1)

Parameter	Specification
Rated voltage	1100 V (Uo/U 650/1100 V)
Conductor	Aluminium or copper to IS 8130; solid or stranded as per size
Insulation	Type A PVC to IS 5831
Inner sheath	Extruded PVC on multi-core cables
Armour	Galvanized steel round wire or flat strip to IS 3975 (see armour selection above); unarmoured available
Outer sheath	PVC ST1 to IS 5831; FRLS to order
Conductor temperature	70 °C continuous; 160 °C short circuit
Sizes	Aluminium power cable from 4 sq.mm; copper control cable 1.5 to 4 sq.mm
Cores	1, 3, 3.5 and 4 core power; multi-core control

PVC cable type designations — IS 1554 (Part 1)

Designation	Meaning
AYFY	Aluminium conductor, PVC insulated, flat steel strip armoured, PVC sheathed
AYWY	Aluminium conductor, PVC insulated, round steel wire armoured, PVC sheathed
AYY	Aluminium conductor, PVC insulated, unarmoured, PVC sheathed
YFY / YWY / YY	As above with copper conductor

Nominal PVC insulation thickness, control cable — IS 1554 (Part 1)

Conductor size (sq.mm)	Nominal insulation thickness (mm)
1.5	0.8
2.5	0.9

Insulation and sheath thicknesses for power cable sizes follow Tables 2 and 3 of the standard and are stated on the drawing issued with each quotation.

Current rating basis

Reference conditions for published current ratings

Reference condition	Value
Maximum conductor temperature	90 °C for XLPE
Ambient air temperature	40 °C
Ambient ground temperature	30 °C
Soil thermal resistivity	150 °C·cm/W
Depth of laying	90 cm at 3.3–11 kV; 105 cm at 22–33 kV

An ampacity figure quoted without its basis is meaningless. Apply the appropriate derating factors for the actual installed condition.

Standard and optional fittingsWhat is supplied as standard, and what is available to order

Manufacturing

Controlled at every stage

Incoming conductor inspection to IS 8130
Drawing and bunching
XLPE insulation extrusion with continuous wall-thickness monitoring
Laying up and inner sheath
Armouring to IS 3975 where specified
Outer sheath extrusion and sequential printing
High voltage and insulation resistance testing
Drum winding, lagging and marking

Also available

Cable execution

Underground cable laying and jointing
Horizontal directional drilling
Cable route survey and trenching
Termination and commissioning
800+ 11 kV line bifurcations delivered

Standards we manufacture and test to

Standard	Scope
IS 7098 (Part 1):1988	XLPE insulated PVC sheathed cables up to and including 1100 V
IS 7098 (Part 2):2011	XLPE insulated cables above 1100 V up to and including 33 kV
IS 1554 (Part 1):1988	PVC insulated heavy duty cables up to 1100 V
IS 8130:2013	Conductors for insulated cables and flexible cords
IS 3975:1999	Mild steel wires, formed wires and tapes for armouring of cables
IS 5831:1984	PVC insulation and sheath of electric cables
IS 10810 (parts)	Methods of test for cables
IS 3961 (Part 5)	Recommended current ratings for PVC and XLPE insulated cables
IEC 60502-1	Power cables with extruded insulation for 1 kV to 3 kV — the export equivalent

Routine and type testsPerformed on every unit, and available on request

Routine tests

Performed on every unit

Conductor resistance
High voltage test
Partial discharge on every screened length (HT)

Type & special tests

Available on request

Conductor properties
Insulation and sheath physical tests before and after ageing
Volume resistivity
Hot set test
Flammability
Partial discharge (HT)
Bending test (HT)
Dielectric power factor against voltage and temperature (HT)
Heating cycle test (HT)
Impulse withstand (HT)

Third-party inspection

Purchaser and third-party pre-dispatch inspection is accommodated on request, including for export consignments. Type-test certificates are issued from CPRI, ERDA or NABL-accredited laboratories — copies available on request.

Inside the works

Inside the cable plant.

Extrusion, armouring and drumming under one roof, with test benches on the same floor.

Walk the whole works

Applications

Where it goes to work.

Utility

Underground distribution

LT and 11 kV underground distribution networks.

Urban

Network conversion

Overhead-to-underground conversion schemes.

Industry

Plant distribution

Internal plant and industrial estate cabling.

Infrastructure

Developments

Township, warehousing and commercial development supply.

What does A2XFY mean?

A = aluminium conductor, 2X = XLPE insulation, F = flat steel strip armour, Y = PVC outer sheath. Replace F with W for round steel wire armour, drop it entirely for unarmoured, and drop the leading A for copper.

Do you make 1.5 sq.mm aluminium power cable?

No, and nor does anyone else — aluminium power cable starts at 4 sq.mm. Sizes of 1.5 and 2.5 sq.mm exist in copper control and instrumentation cable, which is a different standard and a different product.

What is 3.5-core cable and when should I use it?

It is a three-phase cable with a reduced-size neutral, used for four-wire distribution where the neutral does not have to carry full phase current. It is an Indian construction and does not appear in export catalogues, but it is the standard choice for LT distribution here and cheaper than a full 4-core.

Should I specify round wire or strip armour?

Round wire for single-core AC cables, because it can be non-magnetic and avoids eddy-current losses. Flat strip for multi-core LT cable above about 13 mm diameter under armour — cheaper, more compact and easier to bend.

Often supplied together