I've got 46 volts between black wire and earth

[coolhands]

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.

 

[xr4x4]

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)

 

[coolhands]

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.

 

[EFLImpudence]

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.

 

[coolhands]

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.

 

[radioredcat]

In flats that I have seen the landlords fuse is usually in a locked cupboard in the communal hallway.

Andy

 

[AndyPRK]

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

 

[coolhands]

I'm trying to upload some poor pics of the cupboard in the hall:

 

[coolhands]

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)

 

[AndyPRK]

Maybe the stair lights I would think?

What colour fuse is behind the cover ?

 

[coolhands]

has white spots says 5amp. Old fashioned style fuse.

 

[AndyPRK]

For a light circuit or door bell/entry then.

How did u isolate the circuit to change the switch ?

 

[coolhands]

I did not isolate it since I couldn't - I was just careful I will switch that switch off tomorrow and see what does.

 

[xr4x4]

Apparently it's PME earth.

 

[securespark]

I did not isolate it since I couldn't

you don't have an earth!

FFS...