I've got 46 volts between black wire and earth

coolhands

coolhands

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hi. In my communal hallway there are time delay two way switches. One of them burnt out from being stuck on so I decided to swap for new. However, although the light works when connected up as before I observed the back box was 'live' when touched with cheap electric screwdriver so I investigated with multimeter:

with all wires separated, on the feed wire I have 117v between live and earth, and 46v between neutral and earth.

I have not had the opportunity to look in the ceiling rose, could the problem b there? Believe it or not I did ring an electrician to get it looked at, but he basically said if it was working just swap switches like for like. I assume he was thinking I was confused about the voltages / multimeter (which I might be!) but the same method of two way switches inside my flat don't present the same, so I imagine something is wrong.

any advice? Am I overlooking something obvious?

by the way, the communal hallway is shared between two flats in a victorian house conversion. Neither my nor my neighbours CU will switch off the power to this hallway light - we've tried all mcbs. So I assume it is somehow wired between the main elctricity board and our CU's.
 
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If your only getting 117v between live and earth would suggest to me that you don't have an earth!

Have you checked the cu? (Fuse box)
 
thanks. This hallway leads to our two flats. I have one cu in my flat, upstairs neighbour has one in his flat. Neither appear to feed this light from what we can see by switching everything off.

so I need to somehow check the earth wire is actually earthing? Inside my flat, all seems normal. Is it possible the earth wire in hallway or ceiling rose is broken?

I have at the moment made wires safe so not in use.
 
There is likely a 'landlords supply' fuse box.

If this is a communal area between rented flats you should get the landlord to sort it.
 
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there is no landlord we own the property. There is no other fusebox we are aware of, and we've owned them for approx 10 yrs so know the properties well.
 
In flats that I have seen the landlords fuse is usually in a locked cupboard in the communal hallway.

Andy
 
I guess you can't isolate the circuit to work on it?

Try turning off all the cu's and see what else is still working and wether the lights still powered.

A picture of where the mains comes into the building would be good and meters
 
I'm not sure what the single metal box does that says 'on' to the right does. (there are 3 flats '0' is the basement flat)
 
For a light circuit or door bell/entry then.

How did u isolate the circuit to change the switch ?
 
I did not isolate it since I couldn't - I was just careful ;) I will switch that switch off tomorrow and see what does.
 
D

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