hazard light update

[canter]

My last post described a hall light switch that gave a shock when a metal face plate was fitted, in spite of being earthed. The lamp wiring has now been inspected.. it's a huge mess and it looks indeed like one of the earths is connected to a live, explaining the shock. So it's currently staying switched off until the lapm can be rewired properly. There are 5 cables in total attached to the lamp and 4 terminal blocks (T1-T4) wrapped up in insulating tape. Any ideas why there are 5 cables and how an ordinary light fitting could be re-wired to all these...
Cable 1: L>T1; N>T4; E>T1
Cable 2: L>T2; N>T4; E>T1
Cable 3: L>T2; N>T3; E>T2
Cable 4: L>T2; N>T4; E>T1
Cable 5: L>T2; N>T4; E>T1

The lamp is connected L>T3; N>T4
Thanks.

 

[Spark123]

Can you post a photograph
One thing for certain, the CPC (earth wire) should never, ever be used as a live conductor.
//www.diynot.com/forums/viewtopic.php?t=73320

 

[securespark]

Having just drawn out your writings on a piece of paper, I deduce:

T1 = Earth

T2 = Live Loop

T3 = Switched Live (no marker)

T4 = Neutral

But somehow, T1 has a live terminating in it.

But why isn't the CPD operating?

 

[jj4091]

I deduce:

What a lovely word, I haven't heard that used in years

 

[securespark]

Not as nice a word as "flange", my favourite!

 

[RF Lighting]

 

[mdbalson]

RF you seem to be using that picture alot at the moment, is it your favorite picture at the moment then

 

[securespark]

And if there is a direct L/E short as you describe, why isn't the CPD operating?

 

[Spark123]

I'm thinking this is a nightmare setup,sounds like CPCs used as live conductors and vice versa. I think you really ought to be getting an electrician in to take a look before someone gets hurt.

 

[securespark]

This is just a guess, but how about swapping the cpc in T2 for the live in T1??

I'm thinking someone has done a DIY botch on it & got wires in the wrong loc's.

BUT I'M STILL WONDERING WHY THE CPD IS NOT OPERATING!!!!!

 

[mdbalson]

Maybe the earth is not connected at the CCU


Or somewhere else in the circuit


Or if the CPD is a rewire fuse, someone may have used a larger size of fuse wire, or something else conductive.

Or if the CPD is a MCB, could the MCB have failed.

 

[RF Lighting]

RF you seem to be using that picture alot at the moment, is it your favorite picture at the moment then

You may have me confused with someone else.


First time I've ever posted it.

 

[JohnD]

it might have come from someone else...

was Posted: Mon Apr 23, 2007 10:24 am

 

[Spark123]

BUT I'M STILL WONDERING WHY THE CPD IS NOT OPERATING!!!!!

I'm thinking that the cores may have been incorrectly used i.e. if the CPC core is used as a live conductor (about as wrong as it can get) at both ends of the cable it won't operate the CPD, if the L (I take it the OP is assuming they are all lives as they are red?) core is used for earth at both ends the CPD won't operate. For the N, I take it the OP is assuming every black conductor is a neutral.

 

[canter]

Thanks for all the suggestions. I think securespark's 'deduction' was correct first time about T1-T4 - with an earth in the live loop put in by some idiot who used to live here! I don't know why the CPD didn't work, perhaps because the earth wire in the live loop was from the switch cable..?? or maybe because the main earth terminal was in ome bizzare DIY botch arrangement, a bit loose and not attached to anything... there ar eno other problems with earth in the house - all other sockets and switches fine. All that said, can anyone explain what the extra 2 cables are for in the ceiling? i.e. switch, supply, cable to next light... plus 2 more cables? also, what's the best way to test that the earth in the switch is no longer live - a multimeter presumably? what should I look for when testing?