Safety Rules for OHE — Traction Distribution Notes

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These rules are supplementary to the General and Subsidiary Rules (GR/SR). Every OHE maintenance depot, equipment room, switching station, cabin, and related office must display printed boards on electric-shock treatment, and keep First Aid Boxes at every switching station, maintenance depot, OHE Inspection Car, and breakdown vehicle. Ropes, come-along clamps, and Trifor devices must be tested at least once every six months, with records maintained per depot.

Permit to Work

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Exam Focus — The 2m Rule

A Permit to Work must be obtained from TPC (Traction Power Controller) or other authorized person before commencing work on any part of DEAD OHE, or within 2 metres of LIVE OHE — this 2m distance figure is a frequently tested number.

Earthing Before Commencement of Work

Every working party is protected by at least 2 independent earths, one on each side.
If the distance between working parties exceeds 1000 m (1 km), intermediate earths must be added so no gap between earths exceeds 1000 m (1 km).
Even where earthing already exists via isolator switches with earthing heels, ADDITIONAL temporary earths must still be provided — one existing earthing method never substitutes for the other.

Procedure for Providing Temporary Earths — The Exact Sequence

Post men on both sides of the work site to warn of approaching trains on the same and adjacent tracks.
Obtain the Permit-to-Work first, confirming power has been switched off.
Use only a discharge/earthing pole assembly specifically designed for this purpose — flexible cable with at least 40 mm² cross-section, able to withstand short-circuit currents.
Fix the earthing clamp securely to a mast at least one span away, confirming the mast-to-earth-rail bond is intact — check tightness just before connecting the top clamp, since a clamp fixed in advance could have worked loose.
Hook the top clamp securely to the OHE conductor with a snap action, and tie the earthing pole to the mast/structure.
Repeat for the second temporary earth on the other side of the working party.

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Critical Safety Rule — Never Hook the OHE End First

Never hook the top hook of the earthing cable onto the OHE until the OTHER end has first been connected to earth. Removal follows the exact reverse order — first remove the hook on the OHE, then remove the clamp fixed to the rail/mast/structure. Getting this sequence backwards means briefly handling a cable that could still carry fault current.

Discharge/Earthing Pole Assembly — Precautions

Cable continuity between top clamp and earthing clamp checked once a fortnight.
Cable renewed if more than 20% of strands are broken.
The full assembly is inspected by SSE/JE once a month.

Neutral Sections & Sectioning Points

Neutral Sections must be treated as LIVE equipment and earthed separately at two points on either side of the work party before starting work — even though they're 'neutral' in normal operation. When work involves conductors that aren't electrically bonded (e.g. around a sectioning point), each snapped end could be at a different potential, so each end must be separately earthed at two points.

Ladder Safety Rules

Ropes used with ladders must be cotton or jute — metallic ropes are strictly prohibited.
A ladder must be held by one person on the ground while the top is tied to the supporting structure — and must never be positioned to fall on a live part.
Ladders must never rest against the contact wire, and if the work risks the conductor breaking into two parts (sleeve/splice work), trolley ladders must be used instead of resting against the conductor.
More than one person shall not normally be on a ladder; climbing with wet/slippery footwear is forbidden; ladders shall not be used to transport materials; tools should be passed up via rope, not carried while climbing.
No one should stand directly below a work spot under a ladder.

Work Near Parallel Overhead Lines

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Exam Focus — The 8m Rule

No work on any overhead line span running parallel to an electrified track — where the minimum distance to the nearest electrified-track centre-line is less than 8m — may be done without switching off and earthing the 25kV traction line, EXCEPT for 4 specific low-risk items: replacing lamps below the line, painting structures/poles up to 2m from live wires, foundation reinforcement (without prior weakening), and replacing aerial fuses.

Isolators

Isolating switches on the 25kV system must NEVER be opened or closed while current is passing through them. Normally, isolators should only be operated after power supply to the section has been switched off by opening the appropriate interruptor first.

Petroleum Sidings — Special Precautions

10 ohm earths must be connected to the petroleum siding on each side at the insulated joint. Transverse rail bonds required at 30m intervals, all with copper rivets.
No oil tanker may be stabled under live OHE for inspection. Fuelling only via side-filling arrangement.
Minimum 2m electrical clearance from live OHE must be maintained at all times.
During filling/loading and unloading of petroleum products, isolators at the neutral section must be kept OPEN to ensure the OHE is dead and earthed.

Records & Registers

Real, specific registers each depot/sub-depot must maintain: Daily Report of OHE Maintenance, Register for Foot-Patrol Reports, Cantilever Assembly Maintenance Register, Register of Contact Wire Thickness Measurements, Register of Clearance under Over Line Structures, Register of Earth Resistance Measurements, Register of Current Collection Tests, Register of Regulating Equipment, Register for Isolator Switches, Register for Turn Outs and Cross Overs, and Register of Vulnerable Foundations.