Incorrect Isolation Practice and Poor Supervision

Incorrect Isolation Practice and Poor Supervision

Safety Alert No. 64

At approximately 10.00 am on Wednesday 17 August 2016, a second year apprentice sustained an electric shock when disconnecting redundant lighting cable from a junction box during a ‘strip-out’ task.

The Tradesman Supervisor had re-energised the circuit without ensuring the work had been completed.
The apprentice was holding two neutral conductors - one in each hand. In this situation, it is possible that a lethal potential difference can occur between the two neutral conductors.

The apprentice was wearing approved gloves and EGT issued PPE at the time of the incident. With the dry work surface of the scissor lift he was working from, very little current is likely to have branched out to the general mass of the earth. Therefore, the low resistance current path was across the apprentice’s arms and chest.

The Tradesman Supervisor did not follow the host company’s Electrical Isolation - Safe Work Method Statement, which required the switch to be locked out and tagged out. With no lock fitted and tag in place, the switch on the sub-switch board could be easily re-energised, which is what occurred resulting in the apprentice sustaining a serious electric shock.


1. Always complete all steps of the electrical isolation procedure;

2. In this case it was possible for the sub board to be isolated at the site switchboard and this would have been the correct action to take so the sub board had no supply. Apprentices should be mindful of the best isolation methods and try to work with tradesman to ensure they are used.

3. Ensure a lock is applied to the isolation point and each worker places a tag onto the lock;

4. If an apprentice sees that his Tradesman Supervisor or another person is not following the electrical isolation safe work method, the apprentice needs to talk to his Supervisor to assist in implementing a safe system of work by way of correct electrical isolation practice; and

5. If an apprentice feels that he is not receiving suitable support or instruction in safe work methods, he / she should speak with his / her Field Officer as soon as possible and raise the concern.


For any questions or queries, please contact the OSH Team on 6241 6150.