Safety Alert: Electrical Incidents

Safety Alert: Electrical Incidents

Safety Alert No: 39

In the last 2 weeks we had 3 electrical incidents which resulted in 3 apprentice receiving electrical shocks. All three had different root causes and each incident has learning’s that can be taken from them.

INCIDENT 1

An installation of metal cased, interconnected, surface mounted fluorescent lights onto the ceiling grid which was being undertaken. The investigation showed that the correct isolation had occurred and the work practice followed.

When completed the circuit was re-energised it was noticed that the end fitting was not working. The apprentice noticed a gap between the two lights and decided to push the two units together to establish a connection. The RCD did not trip initially due to the heavy lacquered fittings not allowing continuity to earth.

He received a shock as the light fittings were wired incorrectly at the point of manufacture. The polarity of active and earth was incorrect, the switch wire was connected into the earthing terminal and the earthing wire was connected to the active terminal. This made the metal casing become live.

RECOMMENDATIONS

At the point of noticing that the installation was not working, if the circuit was isolated prior to the two units being connected the apprentice would not have received a shock. When re-energised the circuit breaker would have tripped and the fault pickedup at that point.

INCIDENT 2

The Apprentice was adding in an extra Clipsal Cat No 414 socket which was previously a Clipsal Cat No 413 and connecting a new loop with an extra Clipsal Cat No 414.

The apprentice received an electric shock after brushing his left hand on the disconnected neutral. When checked with a multi-meter it was found the neutral conductor had a potential to earth.

The switch board to the floor was shut down and further investigation showed the circuit was still live. It was identified that the sub mains 240 sq. mm neutral conductor feeding the level being worked on Distribution Board wasn’t properly terminated i.e. not secured fully to the Neutral busbar. After correction the circuit was rechecked, tested and cleared of any fault.

RECOMMENDATIONS

This shock could have been avoided if the apprentice had checked with his supervisor that the circuits worked on prior to dis-connection had no back feed, tested before he touched and used his volt stick and followed previous instruction from the field officer around back feed of neutrals i.e. to re-check separated neutrals.

INCIDENT 3

The incident occurred because the apprentice was working in close proximity to live cables. He had tested before he touched the cable he was working on but was not aware other cables nearby were live.

During the investigation it was discovered that:·

RECOMMENDATIONS

Make sure that you and those around you are using the appropriate isolation procedures. Always test before you touch and Make a conscious effort to be aware of your immediate surroundings.

REMEMBER

IT IS EGT’S POLICY THAT NO APPRENTICE ARE EXPOSED TO LIVE WORK. THIS IS DIRECTLY AND INCLOSE VICINITY TO.

NEVER ASSUME THAT AN EXPOSED CONDUCTER IS DEAD.ALWAYS TEST BEFORE YOU TOUCH.

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