IS 7098:1985 Part 2 is the Indian Standard (BIS) for cross-linked polyethylene insulated pvc sheathed cables for working voltages from 3.3 kv up to and including 33 kv. This standard specifies the requirements for cross-linked polyethylene (XLPE) insulated and PVC sheathed cables for medium and high voltage power distribution. It covers both single and three-core cables, armoured and unarmoured, for working voltages from 3.3 kV up to 33 kV. Note: This 1985 version has been superseded by the 2011 revision.
Specifies requirements for XLPE insulated, PVC sheathed cables with copper or aluminium conductors for high voltage applications (3.3 kV to 33 kV).
Overview
- Status
- Current
- Usage level
- Frequently Used
- Domain
- MEP — Electrical Installations
- Type
- Specification
- Amendments
- Amendment No. 1 (August 1987); Amendment No. 2 (June 1989); Amendment No. 3 (September 1993); Amendment No. 4 (July 1999)
Also on InfraLens for IS 7098
BIM-relevant code. See the BIM Hub for ISO 19650, IFC, and LOD/LOIN frameworks used alongside it.
Practical Notes
! XLPE insulated cables have a higher current carrying capacity and short circuit rating compared to equivalent PVC insulated cables due to their higher temperature tolerance (90°C vs 70°C).
! This part (Part 2) is for Medium/High Voltage (3.3kV to 33kV), while IS 7098 (Part 1) covers Low Voltage cables (up to 1.1 kV).
! Strict adherence to the minimum bending radius specified in IS 10810 is crucial during installation to prevent damage to the insulation and sheath.
Frequently referenced clauses
Updates & Amendments4 amendments
Amendment No. 1 (August 1987)
Amendment No. 2 (June 1989)
Amendment No. 3 (September 1993)
Amendment No. 4 (July 1999)
Consolidated list per BIS. For the text of each amendment, refer to the BIS portal link above.
cross-linked polyethyleneXLPEPVCaluminiumcoppersteel armour
International Equivalents
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International Comparison — Coming Soon
We're adding equivalent international standards for this code.
Key Values6
Quick Reference Values
Maximum continuous conductor operating temperature90 °C
Maximum conductor temperature during short circuit250 °C (for a duration up to 1 sec)
Standard voltage grades covered3.3 kV to 33 kV
AC high voltage test for 11kV (6.35/11kV) cable17 kV for 5 minutes
DC high voltage test for 11kV (6.35/11kV) cable45 kV for 15 minutes
Minimum insulation resistance constant (K-value) at 90°C1 x 10^12 Ohm.cm
Tables & Referenced Sections
Key Tables
Table 1 - Nominal Cross-Sectional Area and Resistance of Conductor
Table 2 - Insulation Thickness
Table 4 - Thickness of Outer Sheath
Table 5 - Armour - Dimensions of Formed Steel Wires/Strips
Table 8 - Test Voltages
Key Clauses
Clause 5 - Conductor
Clause 6 - Insulation
Clause 9 - Inner Sheath (Bedding)
Clause 10 - Armouring
Clause 12 - Outer Sheath
Clause 16 - Tests
Frequently Asked Questions4
What is the maximum operating temperature for a cable as per this standard?+
The maximum continuous conductor operating temperature is 90°C.
What is the difference between armoured and unarmoured cables specified in this code?+
Armoured cables have a layer of steel wire or strip (Clause 10) for mechanical protection, making them suitable for direct burial. Unarmoured cables lack this protection and must be installed in conduits or cable trays.
Which code should be referred for conductor specifications?+
IS 8130:1984 'Conductors for insulated electric cables and flexible cords' should be referred for conductor material, construction, and resistance.
What are the standard colours for core identification in three-core cables?+
Clause 7 specifies that the cores shall be identified by colours red, yellow, and blue of the insulation.
QA/QC Inspection Templates
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QA/QC templates coming soon for this code.