RCD on Electric Shower

[jhmklm]

Have recently had an electric shower fitted and a fault showed up just as the electrician was admitted to hospital. Please can someone tell me if they think it is the shower or the wiring to it that is responsible. Supply has been split between the consumer unit and separated RCD unit for the shower.

The RCD trips when you push the on off button on the shower. If the shower is not switched on then the power light on the shower unit is on & RCD remains connected.

Electrician believes it may be a fault somewhere else in the house but he may not be thinking straight at the moment.

I need to know as if it is the shower I need to return it.

 

[rebuke]

There's quite a large number of things it could be - if the RCD unit is just for the shower, then it's unlikely to be anything else in the house though. Possibilities include:

Neutral for the shower has been miswired so it bypasses the RCD (neons on the shower wouldn't draw enough current to make it trip which fits with what you're seeing - it should be fairly obvious from a visual inspection of the inside of the RCD unit if this is the case, but only do this if you feel competent enough to open up the unit etc - safest thing is to get an electrician back).
RCD is actually an RCBO, which is under-rated for the current the shower uses, so is actually tripping due to an over current fault (if you post a picture people will be able to tell you if this is the case)
RCD is faulty (an electrician will be able to use an RCD tester to verify if this is the case)
You have a neutral-earth short somewhere / weak insulation in the cabling (again an electrician can use an insulation tester to determine this).

And of course, it could be the shower is faulty, but I wouldn't automatically assume this...

 

[bongos]

The RCD trips when you push the on off button on the shower. If the shower is not switched on then the power light on the shower unit is on & RCD remains connected. Electrician believes it may be a fault somewhere else in the house but he may not be thinking straight at the moment.

Has this problem only started happening since you had the shower installed? If so then it is more likely to be the shower/installation at fault. If the RCD is tripping immediately when you switch the unit on then it suggests there is a L>E or N>E fault occuring.

Did the spark leave you any paperwork? What is the MCB rating for the circuit? What size is the supply cable? How has the cable been installed? Could it have become damaged?

Need a bit more to go on really.

 

[jhmklm]

Thanks for that it was a wiring fault in the RCD. Electrician sorted it this morning.