Overheating N cable in shower Isolation Switch

[Homer09001]

Just traced a fishy smell in the bathroom to the isolation switch for the electric shower, I found one of the 2 neutral cables had been overheating but I don't know why, it was somewhat loose within the switch but was still sitting within its hole

What could have caused it to overheat?

I've done my research and found the shower requires a 45amp Double Pole switch so I'm off to get a new one tomorrow, is it possible the switch was not rated to a high enough amperage?

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• Homer09001
• 21 Feb 2014
• 1

Thanks in advance.

 

[sparkymarka]

Probably because it was Loose !

 

[sparkwright]

Very common with showers.

A loose connection will have caused this - a terminal not quite tightened enough. Or possibly even a cheap brand switch.

You need a new switch. MK are supposedly the best, they make a similar one (though these have been known to not always work first time).

Most of the cheaper ones seem to wear out quickly too.

The best ones are the Crabtree ones - but they are a very different design. They are circular. But they do seem to last.

You need to re-strip the burnt cable to nice clean copper, so hopefully there is some slack in the cable above.

It is important to tighten the terminals fully. One you have connected it up, before you fix the cover on, give the terminals a final tighten up - as moving the wires can loosen the terminals.

Be sure not to mix up the supply and load cables - as the neon may stay on all the time.

 

[Homer09001]

This is the best I can find at screwfix, they only have a 6a Crabtree
http://www.screwfix.com/p/mk-50a-pull-cord-switch-with-neon/12094#

Am I right in thinking as long as the switch is rated at or above the showers rating it's fine to use?

 

[PrenticeBoyofDerry]

Am I right in thinking as long as the switch is rated at or above the showers rating it's fine to use?

The isolator switch should be rated at no less than that of the current rating of the MCB/Fuse that is protecting the shower circuit.

 

[sparkwright]

Yes, the MK one is fine.

The switch needs to be rated at at least 45/50 amp usually, so 50 amp will certainly be suitable.

 

[Homer09001]

Thank you very much for your help

 

[Homer09001]

Thank you very much for your help