overheating shower isolating switch

[oldfart]

Just read the majority of posts and replies regarding overheating shower switches.
I,ve got a triton bewitch 10.5kw unit, supplied by 10mm T&E over a run of 10mtrs clipped to joists avoiding any insulation material. At the CU it is protected by a 50amp mcb on rcd side.

The supply terminated in the airing cupboard (which backs onto the shower room) at originally a 1 gang surface mounted 44 mm box &
45 amp dp switch then onto the shower unit about 2mts away.

Bit of a squeeze i know which probably helped contribute to the negatives going into meltdown! (noticed on the other posts it was negatives as well! is this coincidence?).

Upon investigation and reading the forum I,ve concluded on a 'slightly' loose connection, not helped by cramped conditions at termination!


I,ve stripped back the damage and replaced the switch with an oblong 45amp dp and 2 gang surface box to try and give me a little more room at the back of the switch , doesnt help a great deal, but i,m happy i,ve got good termination.

Fired up the shower and after about 4 mins cable either side of the switch starts to get warm only first few inches either side though,is this normal? Triton recomend a 45 amp dp switch but i,ve noticed others refering to a 50 amp switch in the forums, and thanks to bas and breezer i,ve found the crabtree 50 amp pull cord which i can use if I re-locate, to hell with the decor have to use trunking. I also notice this will help terminating in the ceiling.

I know i,ve waffled on and not got to the point very well, basically do you have to expect a certain amount of heat build up in the cable either side of the switch?
Will upgrading the switch help?

Thanks for reading

 

[Steve]

cables get warm. it happens. especially in a case like this where they are run close to capacity and in cramped conditions where they can't dissipate heat. Upgrading the switch is a sensible move, yes, as that shower pulls more than 45 amps at 230V (they write those instructions based on 240V, so i believe)

As long as the cable isn't too hot to touch, theres no need to worry. Upgrade that switch quick.

 

[oldfart]

Thanks for your comments crafty, I went to my local screwfix trade counter this morning and bought one of those 50amp ceiling switches from crabtree, "what a beast" that will do the job just nicely, two large seperate cable access holes pre formed in the base to keep cables apart, good solid body plenty of room inside, even has knockouts in the base for mini trunking if coming in flush with ceiling, suprised tlc dont do one of these!
p.s thanks to bas and breezer for identifying it in other threads

 

[plugwash]

cable at max load has a core temp of 70 celcuis so its quite normal for it to have a warm sheath.