RCD protected circuits (sockets problem)

[Murdoch]

How ?

missed the "off" bit!

 

[Lurch]

But it could well be a L - E fault....

Which is exactly why the next step isn't check for an N-E fault.

How ?

Things still plugged in/turned on.

 

[Revved Up Sparky]

Which is exactly why the next step isn't check for an N-E fault.

If you've already tested for a L-E fault and not found one then what other logical step is there to take ? Unless there is a problem with the RCD itself (uncommon) the fault is either L-E or N-E

 

[Revved Up Sparky]

Which is exactly why the next step isn't check for an N-E fault.

Things still plugged in/turned on.

Yes you mentioned that in your first reply to the thread starter. I was assuming everything had been unplugged. Sorry I did'nt make that clear.

 

[Lurch]

If you've already tested for a L-E fault and not found one then what other logical step is there to take ?

Turning off the MCB's does not constitute 'testing for an L-E fault'.

 

[Revved Up Sparky]

Turning off the MCB's does not constitute 'testing for an L-E fault'.

I agree but it's a quick preliminary test which can sometimes give you an indication of which circuit the fault is on. Obviously the most effective method of eliminating a fault on the final circuits is to carry out the necessary IR tests.

 

[Paul2129]

Hi guys, a little follow up on the previous issue. Tonight I've been out all evening, I have t been home since I left for work this morning. I called home, checked in the fridge, and realised that it wasn't on (not blaming the fridge for the issue though (yet)

on the consumer unit, just the "kitchen sockets" had tripped, when reset, it stayed on

the kitchen was renovated about 2 years ago, all appliances are new

the most recent appliance, a coffee machine..... is now under careful surveillance !

oven has its own feed, so stays on with the kitchen sockets tripped

some under unit lights work via the wall switch, but somehow are on the kitchen sockets, as they're off when they trip

other items on sockets are extractor hood, microwave, dryer, usual kettle, toaster etc

ive unplugged most of this stuff now, if it trips, then I can rule a load of stuff out

my (previously electrically troublesome) heating boiler is it it's own room, just off the kitchen, makes me wonder if that is on with those sockets, I guess it's fairly likely, I guess I might investigate that

if I get my electrician to have a look at this lot, will he know what he's testing for ?

thanks as always for your help with this

paul

 

[Blue Duck]

Big switch or little switch? Mcb or RCD? Maybe even RCBO? 

 

[Paul2129]

Hi, the previous time, 'RCD Protected circuits' switch tripped, as far as I think I can remember, only the kitchen sockets stopped working their separate "kitchen sockets" small switch stayed on, as did all the rest of the probably 8 or so separate circuits.

this time however, 'RCD Protected circuits' main switch stayed on, and just the 'kitchen sockets' tripped off

does this tell us anything ?

thanks

 

[ProDave]

If it's just an ordinary mcb that tripped, it tells us it's an overload that tripped it, not an earth fault.

This "kitchen sockets" switch that tripped. Is it Just a "switch" or is there anywhere on it a tiny little button as well?

 

[binky]

reckon socket face-plate screw has snagged cable behind. Oly real answer is to get circuit tested to trace fault.

 

[phil d]

Well I did offer when I was up there the other week, I'd have had a look at it for a couple of pints of Guiness, would have got me out of shopping with the wife.lol

 

[Paul2129]

Please forgive me for not checking back here. ProDave asked about the switch, no I don't believe there are any buttons, it's just a tiny basic switch labelled with just kitchen sockets.

ive had no further issues recently, the next time I have the electrician round, I'll be sure to get him to check out the kitchen circuit properly

sorry to Phil D, that I couldn't save you from your wife, I hope shopping didn't cost you too much

 

[Murdoch]

With intermittent tripping keeping a diary of what was on and when it trips is a must.

Just this week a client complained that they had intermittent tripping..... Turns out the laptop charger was too blame .....

 

[Paul2129]

I do have some notes, kept them in the meter cupboard

 

[Paul2129]

Hi guys, a little update to my electrical problems.... from my diary :

from the start :

15 June : RCD trips

01 July : kitchen sockets MCB

05 Sep : kitchen sockets MCB

After heavy flooding:

23 Nov.: Garage trips RCD

(started working again after a week

14 Dec : downstairs lights MCB

is there any connection between these seperate problems ?

     My biggest problem is the fact that my kitchen is all newly tiled, the rest of the ground floor has hardwood down.... and there’s not a massive amount of floor space. The electrician, rather than seeing this as a challenge, doesnt really want to get involved.

if you’ve any suggestions as to further tests or anoikely cause, please post

otherwise, what’s the best online way to find a very well rated and qualified electrician within about 15 miles of my location ? (Blackpool)

I’m pulling my hair out !

i can remove the dryer from under the kitchen units, there are no tiles under it, we can at least get a good look under the floor, and if needed, I can get a trap cut into the wood floor in the dining room

 

[Sharpend]

What you need is a spark who is competent in testing. 

With kitchen do you have a list of appliances that we're on time? 

As for garage, do you have any leaks or outside lights on garage that may leak? 

 

[Paul2129]

Hi, for the kitchen sockets, I can make a list of appliances, however he’s supposed to have done a test where he sat at his testing meter and I switched on appliances one by one, he checked the reading and found no problem (supposedly)

re the garage, we turned off the isolator switch, and the problem persisted, instantly tripping off, electrician said that this proves it was a problem with the supply under the house, probably a wet junction box. That issue solved itself and hasn’t gone off since

just very odd how randomly these unrelated sounding things in the house are tripping off

 

[Sharpend]

So garage joint is it under ground or against the house wall? 

The fact that the Mcb trips indicates a more serious fault i.e. Live earth short which could be a faulty appliance but then you'd notice this not working, or a wiring fault such as a damaged cable, it may be worth switching kitchen Mcb off and unscrew all socket plates etc to see if a cable has been nicked by screw when fixed back? 

 

[Doc Hudson]

With any problem like this you have to go back to basics to start eliminating some of the unknowns out of the equation. But first a few facts have to be established:-

Do you have any previous electrical test certificates or inspections reports with a full breakdown of the composition of each circuit? Most people don't, but wiring regulations says they should be issued during alterations e.g. fuse box replacements, new amended circuits etc. Also once every 10 years or at a change of occupancy. These documents would show the condition of the cables when they were last tested. Similar to an MOT on a car checking the essential safety elements. But unlike car MOT's there is no legal obligation to test domestic electrical wiring. If you have have no proper testing and formal report issued then in my opinion so far you have proved nothing and isolated nothing out of the equation. 

With your arrangement with only 1 RCD protecting multiple circuits there is a major problem with isolating circuits, because you have no easy means to disconnect the neutral side of the circuit. Any circuit or accessory with a neutral to earth fault can still cause an RCD to trip even if it is switched off, providing any other circuit sharing that RCD has electrical  current flowing trough it sufficient to draw approx 30ma. (The power needed to operate a 6watt LED lamp would be enough to trip an RCD, if there is an earth-neutral fault on any circuit.)

A comprehensive electrical inspection would test every circuit and verify the integrity of all the hidden wiring and test the RCD. But it needs all accessories disconnected from the circuits and depending upon the size of the property and the number of circuits could take anywhere from half a day to a full days work. This testing may identify a cause to your problems. or it may just isolate the fixed wiring and protective devices from list of potential causes. You may eventually find the cause by randomly turning things off/on and waiting  few days, but this is not a method I would recommend. You need an electrician competent at inspection and testing, (some aren't, they are good at installation work but do not have a clue how to fault find), to come and thoroughly test it all.

Doc H.