Have you seem this done before? - Neutral connected to the cpc!!!

[jedisparks]

Hey folks

Saw a naughty one the other day. I went to replace a 2 gang light switch for someone. One of the switches was for the lounge light (fair enough) the other switch was for an outside light, that appeared to have been installed relatively recently (new colours). There was no neutral at the switch so the installer had run a piece of t +e from the switch to the outside light and connected the neutral conductor, from the light, to the cpc in the switch. The earthing system is PME, so obvioulsy the light does work .

But what they are left with is effectively a short circuit when the light is switched on. The circuit is not RCD protected so nothing is tripping out.

I intend to go back soon as poss to do something about it. I've left it disconnected for now.

What i would like to know is what potential problems could arrise from such a practice and can anyone point me in the direction of reg numbers to support my claim that it should be changed.

Thanks for reading.

 

[oxocube]

The cpc is not sized to carry normal circuit currents, so that bodge could mean the cpc overheating and setting fire to something.

I have also seen a steel conduit job where they used the conduit as the N&E, just had one red wire and a N&E link at each socket.

 

[jedisparks]

Thanks

I could be wrong but in the past (well before my time) this was known as an IT system. Where the neutral was connected to the cpc at the point of utilisation. Or did I just make that up? sure I've heard something like that before..... Maybe someone will know.......

 

[telectrix]

if the connection of that circuit's cpc to the earthing bar in the CU were to be lost for any reason, then all conductive parts of that circuit could rise to line voltage and quite easily kill someone. whoever connected that should be shot.

 

[IQ Electrical]

Hey folks

Saw a naughty one the other day. I went to replace a 2 gang light switch for someone. One of the switches was for the lounge light (fair enough) the other switch was for an outside light, that appeared to have been installed relatively recently (new colours). There was no neutral at the switch so the installer had run a piece of t +e from the switch to the outside light and connected the neutral conductor, from the light, to the cpc in the switch. The earthing system is PME, so obvioulsy the light does work .

But what they are left with is effectively a short circuit when the light is switched on. The circuit is not RCD protected so nothing is tripping out.

I intend to go back soon as poss to do something about it. I've left it disconnected for now.

What i would like to know is what potential problems could arrise from such a practice and can anyone point me in the direction of reg numbers to support my claim that it should be changed.

Thanks for reading.

543.4.1 411.3.1.1

 

[Guest123]

TN-C systems are not permitted in consumers installations

 

[Hawk81]

I came across one where some clown had wired an immersion heater by taking a 2.5mm from the CU to an isolator beside the hot water tank. Then from there they took a 2.5mm to the kitchen and used it as a sitch cable for the line. They fitted a 20amp double pole isolator with a neon. To get the neon to work they connected the neutral load side of the switch to earth. They did not properly identify the black as a switched line at either end.

 

[jedisparks]

TN-C system not IT , thats what i meant.

The thing is this was probably done by someone who knew what they were doing otherwise how would they know that the light would work.

Thanks for replies

 

[topquark]

That's combining neutral and earth which I believe is outlawed after the supply head by ESQCR, totally dumb either way.

 

[i=p/u]

if it was done on a steel conduit/trunking job would some voltage not creap on to the metal????

 

[i=p/u]

as its earthed