Help - My RCD keeps tripping?

[thepriory]

Hi, I have absolutely no electrical experience so Im hoping someone could point me in the right direction. My fuse box under the stairs is split . The RCD switch appears to be linked to two further switches being the upstairs sockets and the downstairs sockets. The individual upstairs/downstairs switches dont move, but the main RCD switch keeps tripping. It seems to be when there is alot of equipment running. By alot, I mean ...fridge freezer, two tvs, a playstation, a computer , a washer/drier and a dishwasher. So we're not talking anything over and above the usual family home with two kids really.
It doesnt happen over night. It doesnt seem to be linked to any one item either. Everything is currently off except the pc im using, fridge/freezer, washing machine, and sons playstation/tv.....everything is fine....but if we were to add a few more items (eg dishwasher and kettle) it would trip.
I have read elsewhere that the RCD trips if there is an earth leak? Based on the above, does anyone have an idea what may be causing this? And how to test myself to narrow things down a bit.
I have a friend who is an electrician. Have just phoned him and he suggested unplugging everything and gradually switching back on, if this doesnt solve the problem it may be wiring?
The thing that is confusing me, is that the RCD trip is not instant.... it seems to take a while. Any comments would be appreciated

 

[EFLImpudence]

The RCD trips when the earth leakage reaches a certain level - 30 milli-amps maximum (although usually around 27mA).

This could be an accumulation of small leaks although if it has been alright in the past is more likely to be a heater element or motor failing.

You will not have the equipment to test for this so it will have to be trial and error or a friend who does.

As your friend suggested, you have to unplug appliances, switching off is not enough.

 

[securespark]

I always advise customers to unplug or switch off everything except the burglar alarm, fridge, freezer and CH.

By all means use everything else, but unplug or switch it off when done. That way, if it trips at any one time, you only have a bare minimum of stuff plugged in and it simplifies fault-finding as you can say, "Well, it tripped when there was only A, B, C, D & E plugged in so it must be one of those."

That's assuming it does not trip if you leave it a few hours with nothing attached to the circuits but the wiring.

 

[bernardgreen]

Tracing the fault is not easy and un-plugging appliances does not always identify the location of the fault when it is in the wiring.

Your electrician friend needs to carry out a full insulation resistance test on the wiring to locate the fault.

Some in-experienced "electricians" are un-aware that a Neutral to Earth fault on a switched off circuit can still trip the RCD when an appliance on another ciruit is turned on.

Neutral_Earth_trip

• bernardgreen
• 16 Jan 2011
• 48

 

[ban-all-sheds]

I always advise customers to unplug or switch off everything except the burglar alarm, fridge, freezer and CH.

Fridge and freezer should be OK unplugged for several hours, assuming they are fairly modern, and you don't open the doors.

 

[JohnD]

It is very often a watery item, such as an immersion heater, kettle, central heating pump, outdoor lamp, or garden feature.

Start with them.

 

[pjcomp]

An often-overlooked problem item can be the electric sparker unit on a gas hob/cooker, the plug for which is usually hidden in a cupboard or behind the cooker.

PJ