Safe Isolation in Hazardous Areas — Electrical Procedure Guide

Safe isolation is the procedure for ensuring electrical equipment is completely de-energised and cannot be inadvertently re-energised before maintenance or inspection work begins. In hazardous areas, incorrect isolation not only creates electrical injury risk but also the risk of igniting a flammable atmosphere through re-energisation in a disturbed state.

The Safe Isolation Procedure

1. Identify the isolation point — locate the correct isolator, circuit breaker, or fuse that controls the equipment to be worked on
2. Obtain permit to work — never begin isolation until the PTW is issued and signed
3. Isolate — operate the isolation device to the open (off) position
4. Lock out — apply a lock to the isolation device to prevent re-closure
5. Tag out — attach a warning tag identifying who has applied the lock and why
6. Prove dead — use an approved voltage detection device to confirm the equipment is de-energised at the point of work
7. Apply personal lock — each person working on the equipment applies their own personal lock

Proving Dead in Hazardous Areas

Voltage detection equipment used in hazardous areas must itself be rated for use in the zone. In Zone 1, a non-Ex rated voltage tester is itself a potential ignition source. Ensure your test equipment carries appropriate ATEX/IECEx certification for the zone where you are working.

Returning Equipment to Service

Before returning equipment to service: verify all work is complete, all tools and materials removed, all Ex enclosures correctly assembled with all bolts present and torqued, all cable entries sealed (glands or stopping plugs), and a visual inspection confirming no obvious deficiencies before re-energisation.