The electric shower in my house has been intermittently tripping the circuit breaker in the main consumer unit. First time it happened, a bang was heard in the wall mounted 45A 1 Gang neon switch and the breaker in the main consumer unit cut off. I open the switch and to my surprise I found the live feed (from the mains) was slack. Tightened it with other connection screws pushed back into the box and it worked ok for few hours then tripped again. Did the same thing again and was good until the following morning, the shower was used without and problem then sometime in the afternoon it was tripped again. I then replaced the switch with a new one, put it back again but it tripped after 20 minutes. At this point I was rather puzzled. Called a qualified electrician who kindly came straight away and he initially suspected there must be short connection between the L and N or E somewhere in the 10mm wire. However, he tested the wires at all ends (from the mains to the switch box and from switch box to the shower) and also the shower and found nothing. But he was surprised when he tried to undo the wires from the switch, to find them slack again despite the fact I did tight them again. He tighten them again pushed them back to the box as far as they go then pulled them out slightly, tighten them again then screwed the switch to the box. Since last night and up to now the shower is behaving but I am not holding my breathe. The explanation he gave (which I tend to agree as I trust the guy) is that because the wire is so thick (10mm) when I push the switch back into the deep box the get slack again which create spark inside the switch and this in turn makes the wire hot, increases the resistance and that make the circuit breaker trip in the consumer unit to prevent fire. He also suggested that of this happen again we may need to renew the wire.
I need help with the following:
I need help with the following:
- Has anyone have experience same in the past, if so how it was sorted out?
- Has anyone have another opinion on why this is happening
- Is there another type of switch I can use to secure the connection
- If I need to lay a new wire, can I get away with 6mm instead of 10mm for a shower of 9.5K. 10mm is very hard to lay and connect.