Help - melted plug - why?

[Dan White]

Hi - hope someone can help.

First, quick bit of background. I clean ovens for a living and have a tank in the van for cleaning oven parts. It has a regular 240v imersion element in it which I heat up each morning.

It's connected to an 13a extension cable which is plugged into an outdoor socket.

The outdoor socket is connected to a plug socket inside the house (I drilled through the wall and plug the socket into the household socket. Not ideal, I know. But have been advised it's safe).

Now as I'm lazy I fitted a wifi plug so I can turn it on from bed. It was on for about an hour each morning. I have left it on all night by accident a couple of times, it the element has a thermostat, so presume it wasn't running constantly.

Checked the plug his morning and discovered that it had been getting very hot and had melted the plug to the socket. Everything worked, and nothing had tripped.

Anyone know the likely cause?

 

[Pete999]

Moulded plugtop probably a loose or damaged fuse holder, cut it off and fit a replacement, the socket looks like it needs replacing as well

 

[westward10]

From the burn pattern it does appear to be the fuse part of the plug which has caused the damage.

 

[Dan White]

So def nothing todo with wifi plug (it only turns off 'neutral', so live and earth are always connected and 'open'.?

 

[westward10]

How many kw is the heater.

 

[Dan White]

Yeah, only the fuse area is damaged - the pins are all perfect.

 

[Pete999]

So def nothing todo with wifi plug (it only turns off 'neutral', so live and earth are always connected and 'open'.?

Only turns OFF the N how come? could have something to do with the problem, not sure how or why just yet, the switch in single poll circuit should be in the phase conductor. For some reason you say the N is switched, needs sorting PDQ

 

[westward10]

What kw is the heater.

 

[Dan White]

3kw

 

[Dan White]

Only turns OFF the N how come? could have something to do with the problem, not sure how or why just yet, the switch in single poll circuit should be in the phase conductor.

That's how the wifi socket works. I only noticed as I connected my campervan to the outdoor socket extension - then tested the camper sockets prior to us going away in it. The tester said there was no N. It came on when I realised I hadn't turned the wifi socket on. And that's when I discovered the melted plug. (Hope that makes sense)!

 

[westward10]

You sure you have correct polarity at the socket.

 

[westward10]

If that is loading the plug at 3kw you are over loading it.

 

[Dan White]

If that is loading the plug at 3kw you are over loading it.

Arse. So what's best practice?

 

[Dan White]

You sure you have correct polarity at the socket.

 

[Midwest]

At least we know that Kieron never installed the outdoor socket, 'cos its not flushed in

 

[Midwest]

What about the Wi-Fi socket?

 

[Midwest]

OP, did you purchase the immersion heater/plug top & flex set up, or is it something you put together yourself ?

 

[Dan White]

What about the Wi-Fi socket?

Yeah, everything's wired correctly (polarity-wise)

 

[Pete999]

Arse. So what's best practice?

It's a RECOMMENDATION ONLY that anything over 2KW should be on a dedicated circuit ie not the RFC.
Loose connection at the fuse holder N switched Off arcing at the plug top?

 

[Dan White]

OP, did you purchase the immersion heater/plug top & flex set up, or is it something you put together yourself ?

I bought the immersion - to which I connected the flex and plug. Bought the extension (the highest rated one they did in Homebase) and the wifi thing from Maplin's.