Working Near Electrified Lines Flashcards

You are tasked with carrying a long metal object, such as a ladder, in an area with Overhead Line Equipment (OLE). What is the minimum safe distance you must maintain between the object and the live OLE?

Answer: 2.75 metres (9 feet)

Overhead Line Equipment (OLE) carries 25,000 volts AC. To prevent the electricity from arcing, a minimum distance of 2.75 metres (9 feet) must be maintained between the live equipment and any person or object they are carrying.

A team is working on a line with a DC Conductor Rail (third rail). Under what specific condition is it permissible to work closer than 300mm (1 foot) to the live conductor rail?

Answer: When using approved insulated tools, shrouds, and appropriate PPE under a valid Safe System of Work.

Work is only permitted within 300mm (1 foot) of a live DC Conductor Rail if specific, stringent precautions are in place. This includes the use of approved insulated tools, protective shrouds or troughing, and correct PPE, all as part of a pre-approved Safe System of Work.

While walking in a cess, you discover a disconnected red bond wire hanging from an OLE structure. What is the most critical and immediate action you should take?

Answer: Immediately report it to the Electrical Control Operator (ECO), stating its colour and location.

Red bonds are particularly dangerous if they become disconnected as a dangerous voltage could be present. You must never touch them. The correct procedure is to immediately inform the Electrical Control Operator (ECO), providing the bond's colour and precise location so the equipment can be made safe.

Which of the following statements is true regarding DC Conductor Rails, also known as the third rail?

Answer: You must always assume they are live and dangerous.

A fundamental safety rule for working near any electrified equipment is to always assume it is live unless you have official confirmation (e.g., an Overhead Line Permit) that it has been isolated and earthed. Conductor rails are always live and carry up to 750 volts DC.

A workgroup's task involves using a road-rail vehicle with a hydraulic crane near OLE. The COSS has confirmed the OLE is live. What is the primary safety constraint for the vehicle operator?

Answer: No part of the vehicle or its crane may come within 2.75 metres of the OLE.

The 2.75 metre (9 feet) exclusion zone applies to all personnel, tools, and equipment, including vehicles and plant. The operator must ensure that no part of the vehicle, including any extending parts like a crane, breaches this minimum safe distance from live OLE.

On some lines, particularly in the London Underground area, a fourth rail is present. What is the function of this fourth rail and how should it be treated?

Answer: It is a conductor rail for the electrical return current and must be treated as live and dangerous.

In a four-rail system, the third rail provides the DC power, and the fourth rail, typically located in the centre of the track, provides the return path for the electrical current. It is also a conductor rail and must always be treated as live and dangerous.