33v on earth cable?

[Desie]

Guys

For a while now we have been getting shocks from a metal light switch. I have taken the switch off and looked at the cabling narrowing teh problem down to an earth cable.

I have a T/E cable going directly from a light fitting through the wall and into the switch. I have disconnected both ends of the earth cable and found it is still measuring 33v on a meter.

Can anyone give me any suggested reasons?

Thanks

 

[nozspark]

Induction is what you have, to get rid of it make sure that the earth cable is continuous from the supply, to all your accesories!

 

[Desie]

Noz

The earth was continuous back to source in the first place and was still registering voltage and was still giving shocks. If I revert back its not going to get rid of what was there in the first place surely?

33v induction current in a cable that is barely 4m long and double insulated? Why 33v? Are you sure about your diagnosis?

 

[nozspark]

By supply I mean your fuse board / consumer unit & back to your suppliers earth terminal, not to the light fitting!

 

[GaryMo]

33v induction current in a cable that is barely 4m long and double insulated? Why 33v? Are you sure about your diagnosis?

It's voltage, not current.
I would go along with nozsparks diagnosis as it's something I've come across on a few occasions.

A minor test would be to connect the cable back up again and measure resistance between the metal faceplate of your switch and a known good earth, for example a socket screw on a nearby socket assuming everything is OK there. You should see a very low reading but I bet you don't!

 

[Desie]

Thanks Guys

Noz - By source I meant back to the fuse board. It's the first light in th circuita and I've isolated it for this purpose as well. Ze is also fine.

I've also come across this before as well and correct earthing dealt with it. On this occassion though it seems to be persistent.

Could there be a cable fault causing it?


I think I'll back track all connections again. As its first in the circuit it shouldnt take long.

 

[Spark123]

I'm trying to understand what you are doing, you have disconnected both ends of a CPC in a cable and are measuring 33v from the CPC to where?
You will get odd results from an electrically floating core owing to capacitive coupling and the likes.
What is the result of an R1+R2 test to the switch?