3 pin plug melting

Carawaystick

My dishwasher stopped working the other night.
I'd it plugged into a double extension lead and the sparker fro the hob was in the other socket of the extension lead. The dishwasher plug had melted/welded itself to the extension socket. I seperated the plug frm the socket, the front and back of the socket plastic had deformed, the back of the moulded rubber plug had melted and was black. THe black bit at the base of the live pin had deformed too. but the 13A fuse in the plug worked when I put it in another plug to test it.
The neutral and earth pins were fine, no heat damage. the fuse in the extension lead was grand and no trip swithc in the consumer unit tripped.

How could this have happened? I replaced the plug and cut a foot of the dishwasher lead and now have the two plugs ( dishwasher and clicker for hob) in a surge protected socket adaptor.
I'd be fairly sure the hob isn't an issue, as it's negligible current for maybe a second to light the gas, so there was some current flowing in the live pin of the dishwasher somewhere. it works fine again with the new plug but obviously I'm concerned that this happened.
the house is 5 years old, the dishwasher is less than 2 years old.

Phoenix3

Probably a loose connection causing an arc.A lot of those cheaper extensions such a the pound shop types are of inferior quality and lead to such problems.

Solair

Dishwashers draw quite a serious amount of power when they're heating / drying close to 3000W. They should not be connected via an extension lead.

The socket on the extension lead, as the poster above already mentioned, is probably poorly made and the pins of the dishwasher plug are not making full contact.

The result of this is that the electric current passes through a very small area of the pin on the plug and it gets extremely hot.

This wouldn't make a whole lot of difference for a small load, but for 3000W, it's a lot of power going through a small surface area.

I would suggest that you find somewhere else to plug your cooker. Replace the plug on the dishwasher, with a good quality re-wirable plug with a 13A fuse.

Only connect the dishwasher directly to a proper socket in future!

Rev. BlueJeans

Indeed. I'd even be cagey about using a single outlet extension, but at least that should provide a greater cross sectional area.

The 13A rating is nominal at best. I've been known to use industrial spec ones (the blue lads) where extensions are needed, but cutting the prewired plug off new appliances can, I hear, lead to warranty problems down the line.