UK Live for one cable connected to the neutral of an adjacent cable?

Callcom · Apr 13, 2021

It appears a sparks has connected the live of one lighting circuit cable to the neutral of an adjacent cable using a cable connector in order to obtain a power supply? The circuit has worked fine for 2 or 3 years but has now failed.

While the cable triggers the NCV there is no current or voltage reading. How common is that as a form of providing a power supply? I wouldn't have thought it possible?

Cheers

timhoward · Apr 13, 2021

Callcom said:
It appears a sparks has connected the live of one lighting circuit cable to the neutral of an adjacent cable using a cable connector in order to obtain a power supply? The circuit has worked fine for 2 or 3 years but has now failed

Are the two cables supplied by different circuit breakers or fuses? What was it powering - was it an extractor fan?

Callcom said:
While the cable triggers the NCV there is no current or voltage reading. How common is that as a form of providing a power supply? I wouldn't have thought it possible?

More info needed to determine if it's actually a problem or not. It's common to power extractor fans from lighting circuits and a switched live is often required which might originate from a different cable.

The non-contact voltage detector may be picking up an induced voltage and shouldn't be totally relied upon to prove anything is dead.

streamer · Apr 13, 2021

Where is this connection made? Light, switch, joint box, consumer unit for example. I doubt it's a neutral but more likely a switch wire and most probably not the reason your circuit has failed. I take it an ncv is a clumsy mcb?

SJD · Apr 13, 2021

Just because a cable is coloured black or blue doesn't mean it is a N. In theory if used as L, it should be sleeved (red, or brown) but often that gets missed off. As mentioned, more info needed.

DJAndy · Apr 13, 2021

SJD said:
Just because a cable is coloured black or blue doesn't mean it is a N. In theory if used as L, it should be sleeved (red, or brown) but often that gets missed off. As mentioned, more info needed.

Or lost by the next person to change anything