RCD keeps tripping out - running out of ideas!!!

[Seebazz]

Hi, we suffered a power cut on Sept 30th in the evening, which resulted in the streetlight outside sparking, however since WPD restored the power, our electric has been cutting out intermittently, we previously had an old voltage operated ELCB in place which was changed to a Hager RCD, (not type S).

We have checked all our appliances, painstakingly and have still got the bare minimum switched on, all the things our electrician suggests, the RCD is still tripping, during the week it mainly goes off in the evening, however at weekend it can tend to go off in the day too, one thing that has been pointed out is that the lighting and combi bolier are on the same circuit, with a 6A switch on the fusebox, in the past few days with 70% of the appliances unplugged, except for phone, fridge, freezer and Tvs, it has tripped after someone has had a bath.
A previous electrician suggested a fault on the front ring circuit, but as far we are aware all the appliances and sockets are OK, the only thing that has not been left switched off for a long period is the phone.

So could it be related to the boiler or something else, its no joke when the lights go off when you are bathing a baby, or even when it goes off 5 times when the washing machine is on.

Even as i type this out the power has just gone, 20 minutes after i had a shower.

I have run out of ideas..........i think the electrician might be too........can anyone please offer any advice.....

 

[fireman22]

washing machine 5 times could the motor? did you have the rcd installed before the street light problem or after?

 

[JohnD]

you do not say what rating the RCD is or why you need it. Do you have an overhead supply and/or no supplier's earth, just an earth spike?

If it controls the whole house, it ought to be 100mA. the rating will be printed on the RCD.

A 30mA for a whole house is very likely to have nuisance tripping, you get a bit of leakage from every circuit, the oven, the immersion heater, the boiler and pump, the washing machine, the kettle, the steam-iron - all "watery" appliances and most heating elements. All of these vary, and at times will add up to enough to trip the RCD*

If you don't know what sort of earthing you have, can you post a pic of the Meter, the incoming cable and service head (which includes the supplier's fuse), your consumer unit(fusebox) and the various wires between them?

Have a look near your gas meter and water-main stop-cock top see if they have a fat green-and-yellow earth wire clamped to them.

This will give us some background to your installation which will help us think what the trouble might be.

*my house has a background leakage of about 12mA, half of it comes from the washing machine; but I have an RCD for each floor of the house, so I don't get the cumulative nuisance trips. If there is a trip, it only cuts the faulty circuit so is not much of a nuisance.

p.s. it is very poor practice to have the light go out when the RCD trips, as it can be dangerous if you are e.g. running downstairs; up a ladder, carrying a hot cooking pan... or lowering a baby into the bath. With more information we can suggest alternatives.

 

[Norv]

Heres a suggestion from my limited knowledge.

I had an RCD which kept tripping intermittantly. Tried unplugging things but it still kept tripping & then someone on here suggested testing directly onto the RCD on the load side with nothing connected to it, which revealed an RCD fault. Replaced it & all is ok.

 

[ricicle]

You say the sockets have been checked but did this actually include testing with an insulation resistance tester on the suspect circuits?

 

[Seebazz]

Thanks for the fast reply, i will try and post pics requested tomorrow, in the meantime, the RCD which was fitted 2 weeks ago is a Hager CF284U, hard to tell what the rating is (the text is very small), says 0.3A on top right hand corner.

Gas and water have earth cables attached.
The supply is an overhead supply and an earth spike.
Has tripped 3 more times this evening, by the way has anyone ever heard of a digibox tripping the electric,as this has been suggested as a possible cause, even though we have had it unplugged for a few days and it has still tripped out.

Can't be the washing machine as it was only bought a week ago, but this evening a lot of hot water has been used.

 

[JohnD]

0.3A is 30mA

That is too sensitive for a whole house. The person who chose it was misinformed.

You need a 100mA Time delayed (the time delayed, or type "S" ones are unfiortunately rather expensive)

You can use the 30mA one to protect your downstairs sockets.

All washing machines are prone to earth leakage, even when new. If you can lay your hands on one of those 30mA RCD Adaoptors, as used with lawnmowers, you can carry that round the house plugging suspect appliances in through it.

I suspect that your boiler or its pump are the problem.

Write to your electricity supplier (just use the address on the bill) and ask if they can provide a supplier's earthing point, preferably PME.
That will be better than your earth spike. If they can, it might be free, or it might cost £60 to £100, which will be money well spent.

 

[ricicle]

0.3A is 30mA

.

0.03A

 

[JohnD]

'mmmm, maybe

I hope it isn't a 300mA RCD? not very suitable for a domestic installation.

 

[Seebazz]

Hi Ricicle, in answer to your suggestion, we had all the sockets checked on a tester twice, its gone off now 8 times since 6.30pm, very little swiched on now except upstairs tv, freezer, laptop, internet, phone, fridge, clock radio, bedside lamp and two lights.......all of which have been unplugged previously for at least a few hours.....except for the phone.

 

[JohnD]

and the boiler, I bet.

 

[Seebazz]

sorry forgot, the boilers on too!!!

 

[JohnD]

Ha!

it has tripped after someone has had a bath.....

...Even as i type this out the power has just gone, 20 minutes after i had a shower...

I suspect that your boiler or its pump are the problem.

Ha!

 

[Seebazz]

Just made annother trip with my torch to put the electric back on, had a closer look at the RCD, it says along the top 100A and at the end 0.3A,
as for the boiler for added info, it is a baxi combi boiler, which as i have said previously appears to be connected to the light circuit.......oh its gone off again, now taking two attempts to switch back on.

 

[JohnD]

0.3A? Not 0.03A?



Who fitted that, then?

It is more suitable for industrial use than for houses.

Yoiu have quite a bad earth leakage (if it is working to spec). What do you know about the skill, experience and qualifications of your electrician?

Does the boiler have a switch on the wall, and does the switch have a fuseholder in it? How old does the switch look?

I suspect there is a water leak inside the boiler or its pump, dripping onto an electrical part.

Hurry up with the photos please.