nuisance tripping

sham69

Hi,
Bit of a long one this....
2 weeks ago we got the gas boiler changed (from a really old baxi to a modern on the wall one)
The day the lads installed it we got a power trip on the RCD.
I mentioned it the next day and the lads fobbed me off.
It then tripped every day for the following 4 days (always in the evening/night)
1st time about 8:20pm, then 2nd trip 20 mins later and a third trip 30 mins after that.
2nd day it was an hour earlier but same kind of pattern, 7:20pm , then 20 mins or so later, then 30 mins later.
Landlord (its a rented house) got on the to the gas installer, he got a sparks out to check the wiring on the boiler, he said its all good.
Went around the sockets with some sort of plug thing with 3 lights on it and said all looked fine.
He suggested old school plugging stuff out per room to see whats causing it.
I don't have a problem doing that but my point was , we didnt have a single trip in the 4 years or so previous to the boiler install?

Anyway, went around and tried plugging out different rooms and then marked them off the list etc.
My neghbour (who is a sparks) brought in an rcd plug thingy to test the sockets to see what is causing the trip.
Nothing had really changed plug or appliance wise in the week or so that the boiler was done but the most previous new thing to that was my son's new pc and monitor so I started there.
I plugged the pc downstairs (as we thought his bed might be hitting off the plug socket ) We got a full day with no trip so we thought we had it...
2 days later he plugged in an extension tower (that was originally in his bedroom) as he wanted to plug his second monitor in downstairs..
The power tripped that night..
Aha we said , "it must be the tower"....
So.......
We used the RCD plug thing to test the tower.
I plugged one device into the tower and into the RCD, all was fine for hours.
I decided to plug a second thing in to try and replicate the amount of plugs that were originally in it one by one and it tripped the RCD plug.

Brilliant, we were satisfied that this was defo the cause ...
Thanked the neighbour the next day, threw the tower in the bin and moved on.
That was Sunday.

Last night at 8:20 (yes you guessed it) it tripped again, this time 4 times in the space of an hour.
Washing machine and tumble dryer were on as was the dishwasher.
So we are kind of back to square one...
The strange thing is:
Nothing is programmed to come on at that time of the evening.
The kids get ready for bed so if anything there are less devices plugged in.

I don't know where to go from here.
I am going to leave the dishwasher out for a few days just to see.
Then I presume I try the washing machine, tumble dryer and chest freezer (all in the same socket)

Any advice on this much appreciated.
I presume I just need to plug stuff out, keep a diary and hope to find what has caused it.
My partner is convinced it is something the workers did when putting the boiler in but they have had their work cleared (albeit from one of their electricians, who made it clear to me that he DIDNT work for them but they just use him now and again.
I have ordered one of this RCD plug thingys with the hope of finding the fault using this (although after the Sundays test with the tower I don't know how reliable they are unless the tower was dodgy but we have another issue on top of it)

And breath.....

CaptainCoPilot

My boiler and heating system is not RCD protected. I dont know if its required or not, but it runs on a 3 amp fused spur from a 10A lighting circuit.

I dont know if this is the norm or not, but just highlighting that the heating system/boiler & controls may not be connected to an RCD protected supply, therefore not the cause of your issue.

Im no electrician, but I would try the following the next time it occurs:

1. With the RCD in the tripped position after the fault has occured, switch off all the circuit breakers to the right of it (these are the breakers the RCD are protecting)

2. Turn them on one by one to see if any of the circuits cause the trip to repeat. If this happens, you now know the circuit that has the issue.

3. Find all the sockets on this circuit and plug out the devices. See if this stops the tripping from occuring. It could be a socket itself that is the issue, not just a device, but at least you have now narrowed it down to a single circuit.


There is also the possibility that the RCD itself is faulty, this has happened me before when I was in a rental house. RCD was replaced by an electrician to fix.

meercat

Firstly your heating circuit should be protected by an rcd as all pumps require rcd protection (your setup is fine although I prefer to install a dedicated rcbo for heating systems)

Any competent rec should be able to identity your problem using an insulation resistance test.

Check also that your immersion is turned off

punisher5112

I'd change it so it has its own rcbo and then won't take out the rest of the house.