On Sunday, 20 December 2015 19:31:48 UTC, Mr Macaw wrote:
On Fri, 18 Dec 2015 19:10:46 -0000, Tim Watts wrote:

(Spun off from Chris' thread).

Just noticed my water heater isolator (about 45A load) gets rather warm
after 15-30 mins of operation.

Tightened the terminals - but it seems to be the switch element - the
toggle base gets to perhaps 40-50C by feel. Never noticed before because
I'd never really gone around feeling shower/water isolators under high
sustained loads!

Personally I'd expect a simple switch to be stone cold even under
permanent full load.

Is this reasonable - or time to replace? It's a GET plate - only 6 years
old.

My parents' one gets hot. It's a 15A switch running a 3kW immersion heater. the front plate (plastic) gets to about 40C. When I looked inside there was nothing loose or otherwise untoward, so I bought a brand new decent (MK?) one. It got equally warm, so we decided to just ignore it.

The temperature it gets to depends on the ambient temperature.
You must make sure the cables are properly "nipped by the terminal screws. Some terminals are too big.

Lots of electrical stuff is **** now thanks to the EUSSR and "harmonisation".
Standards have definitely fallen.