Help with light blowing breaker. Not newly fitted.

[Lee Evans]

dining room light suddenly started blowing the lighting breaker in the house.
I’ve had the boards up and can’t see any shorts in the wiring. It happens even when the light fixture is removed.

Flick switch, breaker blows.

Looking for what to try next to be honest.

Any help greatly appreciated.
Lee

 

[littlespark]

Power off. Have a look behind switch… check for damage…

Symptoms suggest a dead short either L to N or L to E on the switched live between the switch and light.


Can we get an idea of age and condition of the installation? Any evidence of rodent damage?

 

[Lee Evans]

Power off. Have a look behind switch… check for damage…

Symptoms suggest a dead short either L to N or L to E on the switched live between the switch and light.


Can we get an idea of age and condition of the installation? Any evidence of rodent damage?

Hi.

Thanks for the response.

The installation is 20-25 years old. I didn’t see any signs of rodent damage on any of the cables. I’ll take another look this afternoon and locate the switch wiring as it’s pretty tricky to get to.

 

[brianmoooore]

Is the "breaker" a MCB or RCBO?
If a MCB, is the circuit also protected by a RCD?

 

[littlespark]

20 odd years old, it should be just a circuit breaker. No requirement for rcd protection at that time of install.

Is there any fixtures directly above the switch? Such as a shelf screwed into the wall or maybe just a picture hook?
Is there more than one switch for the same light?



An electrician on site would be able to test the cables in a sequential manner to narrow down where the fault might lie… and be able to repair without too much upheaval.

 

[brianmoooore]

20 odd years old, it should be just a circuit breaker. No requirement for rcd protection at that time of install.

Requirement or not, I've not installed a domestic lighting circuit without RCD protection for double that.