Swimming Pool Heating Element, Cable Burnt Out

robbo777 · Sep 25, 2012

Hi

I have been asked to look at my mates pool that has a problem, I haven't had a chance to see the problem yet as he lives 2 hrs from me but this is what I have received from him, so just trying to get some info before I get there

The cable that is supplying the heating element from the contactor has burnt out so what I'm asking really is do you have any ideas to what might have caused this?
Firstly I think that the breaker must be of the wrong rating to let the cable overload in the first place, secondly the breaker might be right but the cable is too small for the load or the heating element itself is failing.

Now he says that he only used to be able to have the heater on for an hour at a time anyway due to the cable over heating but it got left on and this is the result.

[ElectriciansForums.net] Swimming Pool Heating Element, Cable Burnt Out

Any ideas would be greatly appreciated.

DNS1 · Sep 25, 2012

The breaker and cable come as a pair... Whatever cable it is, the breaker has to be able to protect it, regardless of anything else.

Is the damage limited to one place? Is it just near the contactor? If so, I'd definitely be looking towards a poor connection.

Engineer54 · Sep 26, 2012

My wild initial guess, is a loose connection, ....99 times out of 100, when seeing that kind of damage to a cable, it'll be caused by a high resistance connection...

plugsandsparks · Sep 26, 2012

If the swimming pool heater amps is within the capability of the contactor and cable, i would say its a poor joint at the contactor. Had one recently on a fork lift battery charger, had to crop a metre of cable out to get back to a decent cable that was not oxidised and had decent insulation.
It doesn't take much to cause that..