I have just bought a small home infra red sauna. The makers say that it can be run through a 13amp domestic plug. Well it can for 20 minutes or so but by then the plug is getting seriously hot to the point that the plastic around the live pin is starting to melt. I'm now on my second plug and third plug fuse. The sauna itself has an RCD but that has never been tripped. The strange part is that the sauna plug is plugged into a domestic extension lead but the plug on this that goes to the ring main barely gets warm. The only thing that I can think might be wrong is that the cable from the sauna to the hot plug is slightly thicker than the extension lead cable - do I remember something from school physics about mixing cables ? The manufacturers are still thinking about this one - any help in the meantime would be very much appreciated.
What rating is the sauna and is it a moulded plug on the lead to the sauna?
The heat can be caused by the load of the appliance or loose connections.
As you have already said the sauna is plugged into an extension lead, and that plug is staying cool, that may rule out load.
It's possible that the socket on your extension lead may not be a tight enough fit when the sauna is plugged into it, or the connections may have worked loose, (extension leads do take some stick, dragged along the floor, dropped etc) so check the socket connections to ensure they are tight. If the connections are tight then change the socket completely.
If the plug on the sauna lead is heat damaged then that will require changing as well.
It was the "loose" plug in the socket. It didn't seem to be that loose but perhaps with a continuous 13 amps for around 20 minutes, anything but "tight" was a problem. Changing the plug and the socket worked first time.