RCD Trips

I have fitted a power shower.

Everything works ok except when isolating the shower via the pull cord it sometimes trips the RCD.
The switch is a brand new MK one with a neon. The RCD never trips if the switch is left on and the shower works as normal, could the switch be faulty?

Any thoughts. Thanks.

You have fitted a power shower

How did you test the installation?

When you say "isolating the shower via the pull cord" I hope you turn off the shower first? Switching such a large load is no good for a standard isolator.

EDIT: is this a shower with an integral heater (rated 7-11kw) or is it a pumped shower (rated 100-200w)?

Crafty..It's a power shower..therefore it draws HOT water from a Combi-Boiler and uses a PUMP to accelerate the water flow and then a thermostatic mixer valve to maintain a balanced temperature by mixing the hot and cold flows.

It is possible that the Neon that is the cause of the problem if it occurs when switching the unit off. I have encountered this in the past, although not common, it does happen. In the first instance I would suggest removing the neon and see if this cures the problem. Remember that the Neon should not be connected to Earth under any circumstances, it should be connected across the live and neutral of the OUTPUT side of the switch.

If removing the neon does not cure the problem, and in all honesty it is likely not to be the problem, then I would suggest a retest of all the circuitry from the Motor all the way back to the board, and include insulation resistance tests.

Stulz said:

Crafty..It's a power shower..therefore it draws HOT water from a Combi-Boiler and uses a PUMP to accelerate the water flow and then a thermostatic mixer valve to maintain a balanced temperature by mixing the hot and cold flows.

Click to expand...

I know what a power shower is. DIYers, however, tend to confuse certain terms, power shower being used to describe any shower with an electricity supply. As the OP has only ever made one post, I tend to assume he is a DIYer.

FAO other DIYers reading this,

Power shower = pumped low-wattage affair that takes hot and cold water

Electric shower = non-pumped high-wattage affair that takes cold water and heats it

The fact that I assume he's a DIYer also explains my reasoning about asking him if he has any test results to tell us. Its very unlikely its been tested, and if it had been, this fault may have been picked up.

It is a power shower as in just a pump and thermostat, no heater.

The RCD trips if you pull the switch a bit slower than normal, a fast positive pull and the RCD stays put.

If you pull the switch half way it trips the RCD. This is why I suspect the switch.

I have a new one which I will fit and see what happens.

When the RCD trips the pump to the shower is not on and the switch on the shower is off.

thanks for the replies Appreciated.