lighting circuit that trips

[feebs73]

Hi can any one help?
I have a customer that says his lights keep tripping out when the shower is on in the ensute and bathroom at seprate times, the wiring is 4 years old the lights are mains gu10 (not ip rated) there is a inline fan with a lv light in it, there is no sign of moisture and no sign of burning cables, i have taken the lights out 1 by 1, also taken the fan out aswell, ended up with none connected, then the mcb stays on, does anybody have any clue?e

Many thanks
Feebs73

 

[bugsy]

have you carried out any testing

 

[Richard Burns]

What is actually tripping an MCB or an RCD?

 

[feebs73]

yes r1 & r2, and insulation test all fine

 

[feebs73]

its the mcb, it is a 16th edition board, shower rcd lights main breaker

 

[bugsy]

Was that with the shower running

 

[1shortcircuit]

Replace the lights for IP rated ones:thumbsup

 

[Richard Burns]

If the MCB is tripping then there is a significant short somewhere; if the IR tests have been done on all conductors and are OK then the problem lies with the lamps or the fan, try a continuity test on the fan and the lamps and see if the values are very low.

 

[feebs73]

yes it is, they are fine when the shower is off, i know it sounds like moisture, but it has been like that for 4 years

 

[feebs73]

i removed the extractor fan to see if that was the problem, but will try the other

 

[feebs73]

Yeah i have thought of that, but as i am not 100% that is the answer, and the cost for the customer if i am wrong.
Thanks anyway.