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Electrical

Neutral fault without any other cables connected!

Anonymous user 23/02/2024 - 3.38 PM

This is baffling me. Installed new cable into a junction box and into the back of a switch. Soon as i went to test, tripped the circuit. Ok, so wire faulty? Got continuity on all wires, nothing crossing. Disconnected switch - so 3 bare untouched wires. Connect Live, works. Connect Earth, works. Connect Neutral Trip. Ok, Left Everything disconnected, connect JUST neutral. Trip. There is NO earth, surely if there was a cable fault, the whole cable would become neutral and it would only trip soon as you connect the live\or earth. Only reason i ask is the cable is now behind a set of stairs, which is a pig to remove\replace. Its defo the correct cable with no other connections. Straight wire A to B Surely this is not possible? UPDATE : My stairs are metal, i suspect a screw has gone through the cable when the stairs were put in. Thus making the stairs an earth, thus the trip. Answered my own question.

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4 Answers

serica electrical

Rating: 5 out of 5
Cardiff
There is a neutral to earth fault in the cable. The screw has probably gone through the cable and is connecting the neutral to the earth
Answered3 February 2021
6

StrangLX

Rating: 5 out of 5
Broadstairs
The neutral is connected to earth via an alternative path other than the CPC, probably a nail or screw is in contact with something else leading to earth... such as your metal stairs. I’m always amazed that there’s enough potential difference between neutral and earth to cause a trip but thank goodness there is!
Answered5 February 2021
1

Mike Mulholland t/a Sparky-Solutions Ltd

Rating: 5 out of 5
Port Talbot
The neutral shouldn’t go into the switch terminal, you’re short circuiting by switching Only a permanent live and a switch wire live back to the light
Answered16 February 2021
1

Anonymous user

Definitely a neutral to earth fault by a screw or nail through the cable which will cause the RCD to trip
Answered5 February 2021
0