Electric shower is tripping the main lights?

[maxinet1]

Hi I recently had a new consumer unit installed but for some reason when the electric shower is turned on it trips the main lights. We have changed the shower circuit breaker to a 40amp, originally it was a 32 amp, and I have also replaced the main light bulbs with energy saving ones with low wattages. But the lights are still tripping? Any ideas would be greatly appreciated!

 

[DCG]

Well I would start by checking all earth connections are made correctly, then if that fails, change the trip switch on the light circuit.

 

[maxinet1]

hi

thank you, i will try that out

 

[TAB]

Is it an MCB or a RCD that is tripping? (A RCD will have a test button on it).

 

[maxinet1]

hi, its the light MCB that is tripping.

 

[DCG]

Could be that the shower coming on is just tripping an overly sensitive MCB, I have heard you can get less sensitive ones, but have never had occasion to pusue that any further

 

[TAB]

A faulty MCB may become sensitive and trip when there is no load on it. The other option would be that the lighting circuit is somehow joined to the shower circuit. A new MCB would be the first thing to try (or swap it around with another one of the same value in the CU) If it still trips then start looking for a installation fault.

 

[maxinet1]

Thanks to both of you for your help and suggestions, will give those all a go next week when i'm at that flat and let you know the outcome - cheers again