RCD tripping - shower booster pump?

[RonMig]

Our house fusebox shown below, was installed in 1995 when the house was ripped open for an extension.
All has been well since then, except -

The green RCD has been tripping lately, most often (but not always) when the pump-boosted shower is switched off.
The individual fuses don't trip, which seems odd? and the shower and all other appliances still work when the RCD is reset.

But the shower pump is about 15yrs old , and lately doesn't always switch on with the shower, so I'm suspecting a dodgy flow-sensing-switch and so will probably just replace the pump.

Does this sound logical / reasonable?
I seem to recall reading on here recently that individual fuses can fail, which surprised me, might this also be an issue here?

Also - any recommendations for a new pump?

 

[dobbslc]

It could be the capacitor on the pump failing. Also why is it sitting in a turkey basting tray, does it leak?
I could also be anything on that RCD ie the sockets upstairs or down.

 

[RonMig]

Haha not yet anyway, but the previous one did (replaced 2009) and I didn't find out until water came through the ceiling.

Not much point to the tray I suppose
- if it did leak more than a slow drip it would soon become useless, as I don't look in there for months at a time

I don't know how to test the capacitor, but will have a look tomorrow to see if it's leaking or something...

 

[angellonewolf]

rcd is a current device that cheaks leaking to earth

mcb are over curret devices so unless the unit thats faulty takes more than 32 amps they wont turn off

they only way unless you have a megger is to remove/unplug/unwire every item untill the trips stop

and remember when disconecting thats live neutral and earth as it could be a leak from neutral to earth not just live to earth

 

[Matrixx]

If the RCD is tripping its usually something to do with water i.e washing machine, immersion heater, electric shower, water pump, the water acts as a high resistance conductor so the current is mA, not enough to trip the protective device but the RCD will pick it up.

As above testing with an insulation tester (500V or a 1000V ) is the only way to find the fault.