Mains Tripping

[PhilÃÂÂ]

Well the missus called me at work yesterday, she was sitting down with a coffee when the sockets RCB thingy tripped.

I sent her into the basement and after pushing it back up, it tripped after about 5 seconds. So, over the phone, we switched all the feeds from the RCB off and the switched them in one at a time to find out which ring was causing the problem. It was the downstairs circuit. So I had her unplug everything, she did and it was still tripping...

Upon arriving home and removing a few sockets from the wall, I found a backplate wet and the socket also. Wondering if the cat had pissed up it I gave it closer inspection. This is the problem....

The socket is on an outside wall of a extension (probably not insulated, single brick). The dishwasher is pressed right up against the plugs in this socket. The dishwasher was about 50% into its cycle and the rear of the machine gets very hot, this and the cold wall is causing condensation in the socket. I have replaced the socket and the washer is not a few inches away from the plugs and socket, but the machine hanging forward from the units is causing the missus to have a moan.

Any ideas of what to do, (apart from getting rid of the missus)

Phil

[TimM]

Swap to a waterproof socket? Hardwire the dishwasher?

[PhilÃÂÂÂ]

A waterproof socket??, Will it stop condensation forming in it???.

[Jerry.]

Sounds like a classic example of a socket in the wrong place, IMO the 'outlet' [1] should be relocated from behind the dishwasher.

[1] preferably hard-wired via a switched fuse connection unit and not a plug and socket.

[Ben Blaney]

I think that would be grounds for divorce - especially if the cable causes welts on the wrists.

[The Natural Philosopher]

Devel Move the socket, and mount off a wood block in oversize hole and full with expanded polyurethane foam. That should insulate it a bit.

Check room moisture levels, and fit humidity switched fan?

Uprate the RCD. Or put the kitchen ring on a bigger one.

[Jerry.]

Doesn't expanded polyurethane foam (the aerosol type) attack PVC cabling ?...

[Steve]

Usually only when provoked.

Steve

[PhilÃÂÂ]

missus)

Upfate the RDC, what do you mean, arn't they all the same??

[The Natural Philosopher]

No, 30mA and 100mA available. At least.

>

[N. Thornton]

or put a surface mount one there spaced off the wall by 3m with matchsticks/nuts/etc, plus add drain holes in bottom of backbox.

yup, or HRV better, or less likely a small dehumidifier.

[usenet]

... and they are for different purposes. In general in a domestic installation RCDs will be as follows:-

A 30mA RCD used to protect a circuit with sockets on it reduces the risk of electric shocks to poeple using that circuit. It's fast enough and

30mA is a small enough current that it *should* not be fatal.

A 100mA RCD (usually time delayed) is protecting the wiring where the earth impedance isn't sufficiently low to guarantee tripping of the overcurrent device if an earth fault occurs. It is neither fast enough nor is the current low enough to protect people from fatal electric shocks, what it prevents is damage to the wiring and possible fire risk as a consequence.

If you replace a 30mA RCD with a 100mA without knowing what you're doing then it could be dangerous/fatal.

[Humbletarotstar]

You'll also find that a 100mA RCD is not 7671 compliant in a domestic installation.

It shouldn't be done.

[Andrew Gabriel]

Rubbish - it is perfectly compliant with BS7671 for what it is intended to do (described accurately above in the text you quoted). A 100mA or greater RCD will actually be pretty much a requirement in any domestic installation with a TT earthing system.

[Dave Plowman]

Since its most common use is filling gaps round PVC windows, I'd hope not.

[Humbletarotstar]

Well spotted.

I should read what I'm replying to first.

It doesn't help to read RCD and see "main" protective device.

[Martin Angove]

Different sort of PVC though, isn't it? "ordinary" PVC versus "unplasticised" PVC. I don't know about polyurethane, but polystyrene leaches out the plasticiser in PVC cables, hence making them brittle. Got a few in the rewire I'm doing now - there's polystyrene *everywhere*

- ceilings, covings, walls...

Hwyl!

M.