Indian Electricity Rules — General Electrical Engineering Notes

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The Indian Electricity Rules govern the construction, protection, and safe operation of electric supply lines and apparatus across India. This chapter covers the specific numbered rules most relevant to General Services installations — supply-line safety, circuit identification, and mandatory protective/emergency equipment.

Rule 29 — Construction & Protection of Supply Lines

All electric supply lines and apparatus must have sufficient rating for power, insulation, and estimated fault current, and sufficient mechanical strength for their duty under actual installation conditions — constructed, installed, protected, worked, and maintained to ensure the safety of human beings, animals, and property. Where BIS codes of practice conflict with these Rules, the Rules prevail.

Rule 30 — Service Lines on Consumer's Premises

The supplier must ensure all supply lines/fittings/apparatus under their control on a consumer's premises are safe and fit for supplying energy.
Underground or accessible service-lines must be insulated/protected against electrical, mechanical, or chemical injury.
The consumer, in turn, must take reasonable precautions for the safe custody of the supplier's equipment, and keep their own installation in a safe condition.

Rule 31 — Cut-Out Requirement

The supplier must provide a suitable cut-out — enclosed in a fireproof receptacle — in every conductor of a service line (except an earthed/earthed-neutral conductor), in an accessible position. Where multiple consumers share a common service line, each must have their own independent cut-out at the junction point.

Rule 41 & 41A — Circuit & Installation Identification

Rule 41: every generating station, sub-station, junction-box, or pillar with multiple circuits (even at the same voltage) must have permanent markings making each circuit readily distinguishable.
Rule 41A: any installation with more than one feed (sub-station, double/four-pole structure, etc.) must be permanently marked as readily distinguishable from other installations.

Rule 42 — Accidental Charge

Circuits and apparatus must be arranged so no part can accidentally become charged beyond its intended voltage limits. Where AC and DC circuits share the same support structure, they must be arranged and protected so they cannot contact each other while live.

Rule 43 — Protective & Emergency Equipment

What Every Generating Station / Substation Must Have

Fire buckets with clean dry sand, plus fire extinguishers rated for electrical fires — conspicuously marked. Extinguishers must be tested at least once a year with records maintained.
First-aid boxes, accessible during all working hours, kept in charge of a person trained in first aid (except at unattended sub-stations).
Gas masks — mandatory (2 or more) at generating stations of 5MW+ capacity and enclosed substations of 5MVA+ transformation capacity, for fire/smoke events. Each generator ≥5MW gets its own set of at least 2 masks.

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Exam Focus — The 5MW/5MVA Gas Mask Threshold

Gas masks are mandatory ABOVE the 5MW (generating stations) / 5MVA (substations) thresholds. BELOW those thresholds, gas masks are only required 'if so desired by the Inspector' — a discretionary requirement rather than an automatic one. This distinction (mandatory vs discretionary) is a common exam trap.