70 volt potential from appliances to earth

[Albumen]

I am not an electrician, but I'll get one in. In the meantime, for safety and to see if I can use them:

Had a (bit) of a flood in the laundry (overflowing sink). No more than a couple of mm on the floor. More a very big leak. Moved tumble dryer and washing machine out to mop up.

When pushing tumble dryer back in made contact with stainless steel sink. Bit of a tingle. Tried it a few more times, same thing.

So, out with (digital) voltmeter. With the tumble dryer plugged in, but the power on the socket OFF, there's about 70 volts a.c. between the bare metal case at the back of the tumble dryer and the sink. Though I can't see that the sink is actually earthed anywhere. Same between the tumble dryer and the gas supply to the boiler (which I think is the only continuous metal pipework).

The washing machine is plugged into the same socket, and the same thing happens there (except I can't get from the washing machine to the gas, so just testing to the sink).

It's as though 70 volts has got onto the earth (or the neutral?) of that socket. Maybe. The whole installation has RCDs at the consumer unit, which is about 3 years old. And none of them have tripped through this.

I've just 'tested' by touching the back of the tumble dryer and the back of my hand on the gas. Definitely more than a tingle, won't be doing that again, I'm on beta blockers as it is. Still not tripped anything. The RCDs (MK) have a test button and all seems OK.

As I say it looks like the washing machine is the same, so probably the double socket rather than the appliances.

Questions:

1. Any ideas as to cause?

2. Are they safe to use (for the next few days), given that none of the touching-two-things-at-once as tripped the RCD?

Many thanks for any suggestions.

 

[Risteard]

Main protective bonding may not be in place. You need to get an Electrician out.

 

[Albumen]

Thanks for the reply.

You mean the thing that the Yorkshire Electricity Board (in my case) did? They changed us onto PME about 15 years ago.

Have left message for electrician. And will keep trying till I get one.

I'll probably try a similar test somewhere else in the house if I can find there something thats the same sort of situation.

Do you think the appliances themselves are safe to use? In terms of catching fire or whatever?

 

[Albumen]

OK, another update. Wife super safety conscious (good) worried about using machines - 'could we run them from a different socket' she asks. Brilliant, I've got a super thick extension, plugged into that I don't get the voltage.

The socket that is (maybe) the problem is a spur off a ring main. If I plug into the double socket that the spur comes from I don't have a a problem. So it looks like the spur socket is the problem. I'm working the next couple of days, but if I haven't got an electrician by Thursday I'll have a look myself. It's surface mounted and as far as I remember Part P allows the householder to replace like for like?

 

[flameport]

I remember Part P allows the householder to replace like for like?

Part P 'allows' anyone to do anything, it's entire content is:

Reasonable provision shall be made in the design, installation, inspection and testing of electrical installations in order to protect persons from fire or injury.

 

[EFLImpudence]

You may find a loose/disconnected earth wire.

Check where the spur comes from as well.

 

[Albumen]

I fancy replacing this socket anyway. It's a cheapo plastic one. Given it's position (under the sink) the cable side entry seems a bit sub optimal. And the wire slopes down into the socket, so any water that gets onto it will flow down, of course. I fancy a nice metal MK one with cable entry from underneath. To be honest we weren't that impressed with the electrician that did this. Wires are clipped direct to the wall (shouldn't that be in trunking?). Though I don't know if I'll go for the MK RCD one - it's £80 and there's RCDs all over the consumer unit.

 

[stillp]

A metal one won't work any better, and might go rusty.

there's RCDs all over the consumer unit

No point in having an RCD socket if the existing one is already on an RCD-protected circuit.

 

[securespark]

made contact with stainless steel sink. Bit of a tingle.

Ouch. Don't do that again.

Tried it a few more times, same thing.

 

[flameport]

Wires are clipped direct to the wall (shouldn't that be in trunking?)

Clipped direct is an acceptable method.

 

[Risteard]

OK, another update. Wife super safety conscious (good) worried about using machines - 'could we run them from a different socket' she asks. Brilliant, I've got a super thick extension, plugged into that I don't get the voltage.

The socket that is (maybe) the problem is a spur off a ring main. If I plug into the double socket that the spur comes from I don't have a a problem. So it looks like the spur socket is the problem. I'm working the next couple of days, but if I haven't got an electrician by Thursday I'll have a look myself. It's surface mounted and as far as I remember Part P allows the householder to replace like for like?

Sounds like the socket circuit in the kitchen isn't earthed then. As I said earlier, you need to get an Electrician ASAP.

 

[JohnW2]

Sounds like the socket circuit in the kitchen isn't earthed then. As I said earlier, you need to get an Electrician ASAP.

It sounds as if the 'spurred socket' may have lost it's earth connection, but it also sounds as if the rest of "the socket circuit in the kitchen" probably is 'earthed'.

Kind Regards, John

 

[Albumen]

Thanks for advice folks. Actually none of this is in the kitchen, it's a separate laundry room. The ring main socket and the spur are in the same room, maybe a whole 5 feet apart as the crow flies. Somewhere I've got one of those neon circuit testers that I used to carry round when I was doing gigs (yes, I know, safety conscious musician, who'd have thought it?).

This is an unplastered* bare brick wall. So is cable clipped to the wall, left exposed, OK then? I don't used it as a workshop, it's not a thoroughfare and it's mainly tucked out of the way.

*according to the spell checker it should be an unflustered brick wall.

 

[winston1]

Agree that you have almost certainly lost the earth on the double socket.

But you should not run a washing machine and tumble dryer off the same double socket. You may get away with it if you don't run them both at the same time, but can you guarantee that?

 

[Albumen]

Agree that you have almost certainly lost the earth on the double socket.

But you should not run a washing machine and tumble dryer off the same double socket. You may get away with it if you don't run them both at the same time, but can you guarantee that?

Oh right, I didn't realise that. Yes, they sometimes run at the same time. No problems so far. Will that be an overload then?