What are the standard conductor materials allowed?

The standard covers both plain annealed copper and aluminium conductors as per IS 8130.

What is the colour scheme for cores?

For multicore cables, the core colours are defined in Clause 10 (e.g., Red, Yellow, Blue for 3-core cables).

Is this standard applicable for outdoor, direct burial installations?

This part is for unarmoured cables, which are generally not recommended for direct burial. Armoured cables as per Part 2 are suitable for such applications.

IS 7098 Part 1

: 1988

Cross-linked polyethylene insulated PVC sheathed cables for working voltages from 1.1 kV up to and including 3.3 kV

CurrentFrequently UsedSpecificationBIMMEP · Electrical Installations

Archive.org BIS Portal Google

This standard specifies the requirements for single and multicore cross-linked polyethylene (XLPE) insulated and PVC sheathed cables for power distribution. It is applicable for working voltages of 1.1 kV and 3.3 kV, covering constructional details, material properties, dimensions, and testing methods to ensure product quality and operational safety.

Specifies requirements for XLPE insulated, PVC sheathed cables with copper or aluminium conductors for medium voltage applications (1.1 kV to 3.3 kV).

Quick Reference Values

Maximum continuous conductor operating temperature90 °C

Maximum short-circuit conductor temperature250 °C (for a duration up to 5s)

Rated Voltage (Uo/U)0.65/1.1 kV or 1.9/3.3 kV

AC High Voltage Test for 1.1 kV grade3 kV (rms) for 5 minutes

AC High Voltage Test for 3.3 kV grade7.5 kV (rms) for 5 minutes

Minimum Insulation Resistance Constant (K) for XLPE1 x 10^12 MΩ-km at 90°C

Key Formulas

R_t = R_20 * [1 + α(t - 20)] — Conductor resistance correction for temperature

Practical Notes

This part covers unarmoured cables. For armoured versions, refer to IS 7098 (Part 2).

Current ratings are not specified in this standard; refer to IS 3961 for guidance, applying necessary derating factors for installation conditions.

Ensure minimum bending radius (e.g., 12 times overall diameter for multicore cables) is strictly maintained during installation to prevent damage.