How to check a 3 pin SOCKET?

[crestamum]

We have just had to replace our dishwasher, the old one having tripped the circuit (please forgive incorrect wiring-tech-speak). New one arrived today, followed all instructions BUT the socket to which it should connect has obviously blown. All other sockets on that circuit are fine. So... my question is: how easy is it, having switched off that circuit at the mains, to unscrew the socket and see what the problem is? I have searched the forums and no-one else seems to have come up with such a, perhaps ridiculously stupid, question. If it is relatively simple, I don't want to drag my electrician halfway across the city for a 5 minute job.


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You mean "socket" not "plug".

I have altered your title. Hope that's OK

Mod Rupert
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[JohnD]

It should be easy...

Buy your new socket first, and examine it before fitting, the layout will be similar to the old one. Get a good brand like MK or Crabtree, easily available in your high street, not some cheap brand).

When you remove the two small screws at the side, the white face-plate should pull forward (don't pull hard, it should easily come out a couple of inches, but will be retained by the wires).

You should find there are three terminals. Two of then will be shielded by plastic to prevent accidental contact. One should be marked "L" and have one, or two, or three cable cores going into it, which will be covered in red plastic insulation (or brown, in a new house). The other should be marled "N" and have one, or two, or three cable cores going into it, which will be covered in black plastic insulation (or blue, in a new house).

One terminal will probably be brass with no plastic round it, marked "E" or with a digram of a Christmas tree on it. This is the Earth. It should have one, or two, or three cores going into it, which should be covered with green-and-yellow sheathing (this sheathing may be missing but you can buy a small amount at the shop where you buy your new socket; it is very cheap). There may also be a short length of G&Y connecting the faceplate earth terminal to an earth terminal in the wall box.

The number of Red cores should be the same as the number of black cores, and the number of G&Y cores.

Observe all the wires for signs of looseness, damage or overheating (report back here on what you find)

Put the cores into the new terminals, deep, tighten firmly with a screwdriver of the correct size. Then go and have a cup of tea and a biscuit, when you come back tighten them again (copper wire is soft and can deform slightly to accommodate the screw).

 

[industryspark]

Right

explain a bit more about what happened with the old dish washer. how do you no it was broken?

what do you mean, blew the socket? do you mean blew the fuse in the plug? blew the ring circuit main fuse/mcb?

 

[crestamum]

I am really grateful to both of you.
John D: will discuss with my husband tonight and MIGHT take a deep breath in the morning and be brave. On the other hand, p'raps a help, help call to our extremely nice and competent electrician is the answer... I think this might come under the heading of an SEP (somebody else's problem).

Industryspark: Came downstairs one morning last week and the dishwasher had not finished its cycle and the guzzler wasn't working. So looked at the fuse box and the switch had tripped. Put it back on again, set the dishwasher going and there was a fairly loud and ominous 'pop'. Switch had tripped again. Husband came downstairs, demonstrated the problem (more ominous 'pop'). Given that it was about 12-14 years old, undid dishwasher, hauled it outside and went off a bought a new one. It did not occur to me to plug the old machine into a different socket.

Funnily enough, I am not blonde.

 

[JohnD]

Might have been a faulty flex, or plug, or socket. If you are using a double socket, with two heavy-load appliances plugged into it (e.g. a dishwasher AND an oven or a washing machine or a tumble drier or a heater) then the socket will be overloaded and will have overheated. A double socket can safely take one large, and one light, load at the same time. Two occasional intermittent loads like a kettle or toaster is OK.

It is also possible that the MCB had been weakened by repeated tripping, or that you had a large number of heavy load appliances on socket circuit. However if you say that all the other sockets are working, and this one is not, then there does appear to be a socket fault. This is quite likely due to impact, nail, or overheating, which you should be able to detect by eye.

FYI, because our splendid UK plugs incorporate a 13A (or lower) fuse, a faulty appliance will not often trip the MCB due to overload more than once, as the plug's fuse will usually fail at about the same time (unless the overload is moderate or slight, in which case the plug's fuse will fail and the MCB will not).

 

[industryspark]

ok

suggest you try what john d has said. have a look in the back of the socket (power off of course) and see if you can see anything.

might be a connection has come loose or been blown away. be certain that the socket is dead before doing this though. let us know what you find.

 

[RF Lighting]

If you have a digital camera then take a pic of the wiring behind the socket and post it on here. It will give us a much better idea of what the problem is, and then we can advise you what to do next.

We love pictures

 

[crestamum]

Can't thank you all enough for taking such trouble - it's enormously appreciated.

John D: don't think the socket (it's a single, in the dishwasher recess) should have been overloaded. Dishwasher is programmed to come on in the middle of the night so nothing else is on. (Washing machine also comes on with a timer, but it's on a different circuit).

So I think that the wiring behind the socket is, as you all suggest, at fault. I will let you know the end of this small domestic saga... thank you very much.

 

[JohnD]

We love pictures

Remind me to show you my holiday snap of the sailing dinghy.

 

[crestamum]

Erm I am feeling about 2 inches high and a right pillock.

Husband has just telephoned and reminded me of the isolating switch for the dishwasher above the worktop. Guess what - when this is switched on, together with dishwasher socket - everything works. So am now planning to buy industrial bottle of bleach, as blonde is the only way forward. Which, together with crimson complexion, will not be a pretty sight. Directions to large hole (for swallowing purposes) now being sought.

Howeffa, I am going to print out the advice so that if I ever DO need to check a socket, I will not waste your time again. And change username to MinusIQMum.

 

[Steve]

Bless!!!! lol its not the daftest thing i've ever heard!

Out of interest, does your meter have 2 readings? Or do you have 2 meters? If neither, there is no financial benefit of having the dishwasher and washing machine come on at midnight.

 

[crestamum]

It's pretty daft... not quite as bad as the post about the house fire, ganja etc. But up there, certainly up there. It's the waste of everyone's time that gets me. I am a.... well, it would probably be moderated out. Plonker might squeeze through.

No, we don't have 2 meters. It's a hangover from economy 7 and it's just nice to come downstairs in the morning and have clean dishes and clean clothes.

 

[Adam_151]

It's a hangover from economy 7 and it's just nice to come downstairs in the morning and have clean dishes and clean clothes.

Where have I been going wrong?!

 

[securespark]

crestamum....do you drive one or drink it?

 

[JohnD]

She's a tobogganist.

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