On 18/12/15 19:32, ARW wrote:

I would expect the cable could be at 40C at that load.

However if you suspect that the switch is getting hotter than the cable
then swap the switch [1] as it is only a few quid and see what happens.

[1] A Yorkshireman can spend other peoples money:-)


Thank you Adam. Did not think to check the cable. IIRC I used 10mm2 for
that one.

Thinking P=I^2 x R, even if the switch has a contact resistance of
0.01 Ohms, that, for I=40A, would be 1600 x 0.01 = 16W developed across
the contacts. In a fully plastic enclosure, I guess that is actually
quite a bit of heat. Could be reasonable I suppose...

Yeah - I'll get a new switch of the same make (for same terminal layout)
next time I'm up TLC in a week or two.