burnt 3 pin plug.

Sep 09, 2008 32 Replies

I was moving a washing machibe in a friends flat last night, and I noticed that the 3 pin plug has signs of burning around the live and neutral pins - not too serious - just enough to discolour the plastic and turn it brown.



What could cause this to happen?



Thanks, Mark.


agreed - always use the best sockets in the kitchen or utility room where heavy load appliances will be connected. However, it could be loose connections.

Why would a cheap socket cause this to happen?

Thanks, Mark.

Corrosion in the socket and on the plug. Causes arcing RF interference and heat.

Really replace both plug AND socket. It's not *likely* to catch fire, but its happened..

Insufficient contact area with the plug.

Plugs and sockets SHOULD wipe corrosion off when unplugging: Typically with a washing machine tis never happens, so if there is a small contact area it can get corroded enough to cause a problem.

Thinking about it, a smear of silicone grease on the plug new plug that you are going to install with the new socket should help a lot..

The metal wipers in the socket holes do not touch the pin over a big enough area or firmly enough to give the minimum contact resistance or cut through surface dirt/oxidation. This leads to heat and more oxidation, leading to more heat.

This can happen over time with a decent socket - it never hurts to unplug and plug back in every now and then (once or twice a year) to remake the contact. Also loose wires inside a rewirable plug (not usual on a washing machine now) can cause the same heating problem - check screw tightness too if the plug is rewirable.

So there couldn't be a more sinister wirig problem at the root of this?

Thanks, Mark.

As an aside - MK was derived from "Multi - Kontact". Their patent was to ensure better contact in the days of round pins - when many makers were using a fairly simple round hole, MK introduced spring loaded sectors to make better contact.

Incidentally, the type of plastic does not discolour easily - so I think if has been seriously hot. The wires in the socket may be damaged. Take care!

Yes. Although a really mean DIYer will fiddle clean tighten and re-use, frankly if a plug/socket is gone that far, I say spend a little money and do the job properly.

Its not as if a 13A plug and a quailty 13A faceplate are going to set you back much more than a tenner is it?

Loose terminal screws and/or fuse clips in the _plug_ is the most common cause of this. If discolouration is evident I'd replace both plug and socket as a precaution. Ensure that all terminal screws are really tight, that the end-caps of the plug fuse are clean and that the fuse is gripped firmly by the clips in the plug. Also ensure that the plug's cord grip is correctly used and firmly clamps the sheath of the flex.

Not using MK sockets, not pushing it in properly, hanging weights on the flex, getting it covered in corrosive chemicals, ..

I would go for a cr@p socket or not pushing it in well.

Thanks guys - I shall advise they replace plug and socket!

Thanks, Mark.

Loose connections within the plug. Loose connections to the fuse. Poor quality socket. Grease etc got onto the socket or plug pins. Plus a few others I can't remember.

MK *may* have been superior to some other makes many many years ago but not anymore.

Of course unless it's pretty old it has probably got a factory fitted moulded on plug. I dunno how these are connected to the flex - crimped?

I don't think they are inferior to any ATM.

I accept that - standards have improved - unless you buy absolute tat. (Avoid Pound Shops and Sunday markets!)

All good brands will meet the proper requirements.

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