Really struggling to find cause of tripping

[midas]

Hi
Hope somebody can steer me in the right direction...

The main switch on my board keeps tripping.

Firstly this may be the cause or a complete red herring.

A few months back I had the same tripping problem and at the time I had a leaky radiator upstairs that had soaked the carpet and had also started running slightly down the walls in the room below so I had a 2kw fan heater blowing on to the carpet to dry it out. The main switch started tripping so I assumed that was somehow the cause as whenever we plugged the heater back in it tripped. However If I remember correctly I switched off that circuit
but the main switch kept tripping so I had an electrician look at it and after some tinkering on the main board told me the neutral was very loose which could have caused the tripping after which everything ran fine.

Yesterday we noticed the same rad had started leaking again and we went through the same fan heater routine followed by the same tripping routine.

This time I simply kept resetting the trip (leaving the heater unplugged) but again the main switch kept tripping I even tried leaving various individual circuits off but couldn't establish which circuit was causing the problem.

What was happening though was that each time I reset the main switch it would take longer and longer to trip and eventually last night with all circuits running (no fan heater) everything was fine.

This morning however 6 o'clock boiler comes on 6:10 I turn on a 2kw fan heater in my kitchen (not the same heater) put the kettle on and go to the fridge to get some milk and the main switch trips.

Reset the trip, it trips out. Unplug the kettle reset the trip seems OK. Plug the kettle in it trips. Unplug the kettle reset the trip works ok. Plug kettle in to different socket main switch trips.

For a while I turn on all the light circuits but not all the mains circuits but do boil the kettle which finishes the electricity runs a while longer but then trips.

I reset it and it runs OK so I turn on all the main circuits and it's been fine now for a couple of hours.

One thing I did notice whilst at the board was that the main switch would sometimes buzz as if it was about to trip but then not.

Can anyone please shed some light on my problem or give me some guidance on how I can isolate the problem.

Also in the good old days only the circuit that was causing the issue would trip so why do boards not do that now?

Help much appreciated.

 

[bernardgreen]

Assuming the "main switch" is in fact an RCD then it is an earth leakage fault that is causing the trip.

The fault can be a on a circuit that is switched off at the consumer unit ( MCB off or fuse removed ).

Neutral_Earth_trip

• bernardgreen
• 16 Jan 2011
• 48

The fault in the diagram is a neutral to earth short but equally a resistive fault such as damp between neutral and earth will have the same effect.

 

[midas]

Assuming the "main switch" is in fact an RCD then it is an earth leakage fault that is causing the trip.

The fault can be a on a circuit that is switched off at the consumer unit ( MCB off or fuse removed ).

Neutral_Earth_trip

• bernardgreen
• 16 Jan 2011
• 48

The fault in the diagram is a neutral to earth short but equally a resistive fault such as damp between neutral and earth will have the same effect.

Hi
Many thanks for your quick reply.
It's now about 4 hours since the last trip and all is working OK.
So do you think it's again linked to my leaking rad maybe causing damp in the wiring and if so will it rectify itself as it dries out?
If not how do you go about finding where the fault lies?
Also (sorry for lots of questions) why did it run fine overnight and then start going haywire again this morning?

BTW the board is a Memera 2000 board.


Thanks again.

 

[Taylortwocities]

When an RCD starts tripping at regular times, look very closely at things that have the same time of operation, especially where water and electricity might meet (they never should…).

My first suspect will be central heating system. Leaking pumps and valves will cause you problems!

 

[midas]

When an RCD starts tripping at regular times, look very closely at things that have the same time of operation, especially where water and electricity might meet (they never should…).

My first suspect will be central heating system. Leaking pumps and valves will cause you problems!

Ok thanks for that.
All has been well since about 7 A.M. but we'll see what happens at 6:00 A.M. tomorrow when the central heating starts again.

 

[ekmdgrf]

Could the radiator being leaking onto something under the floor? Junction box or something?

Could also be that the RCD is on the blink.

 

[midas]

Could the radiator being leaking onto something under the floor? Junction box or something?

Could also be that the RCD is on the blink.

It's possible as on the ground floor where the water ran down the walls is directly above a socket.

I strongly suspect it's to do with the radiator as it's the same problems I had when it leaked before which eventually cleared itself up after i sorted (or i thought I sorted) the water issues.

Hopefully it will again but if not I'll report back..

Thanks

 

[midas]

Looks like my theory of the wet socket in the lounge may not be correct.
Today's episode:

6:00 Central Heating On
6;10 Fan Heater, Toaster , Cooker NOT IMMEDIATE TRIP /RESET
6:11 Fan Heater IMMEDIATE TRIP /RESET
6:12 Kettle IMMEDIATE TRIP / RESET
6:13 Kettle boils fully on different ring circuit in hall OK
6:20 Kettle, Fan Heater , Cooker , Toaster all on at same time in kitchen again ALL WORKING OK NOW


I've started by trying to eliminate the heating so tomorrow it will come on at 6:30

Can somebody shed some light on this please?

Thanks

 

[ekmdgrf]

When an RCD starts tripping at regular times, look very closely at things that have the same time of operation, especially where water and electricity might meet (they never should…).

How do you split water into Hydrogen and Oxygen?

 

[ekmdgrf]

Also in the good old days only the circuit that was causing the issue would trip so why do boards not do that now?

In the good old days the circuit was only protected for over current by a fuse or MCB. Then someone decided earth leakage protection would also be a nice thing. Problem was that a MCB costs £3.50 and a RCD costs £30. Someone thought £500 for a new board might be hard for the consumer to swallow, so you have a group of circuits on a single RCD.

Regarding your ongoing issue, it's a bit of a pita. You need to find the common factor. What causes it to trip. That can be hard to narrow down. It could be the appliance, the circuit or the RCD itself. It's likely not the appliance, since you've had different ones causing the trip. It seems to be that it trips under high load, when the fan heater or kettle comes on. Could also be that there is a small fault somewhere and some of the appliances are pushing it over the edge. It's interesting that you observe that the RCD is buzzing though.

Do you have a dual or single RCD board? Perhaps you can post a picture of it here?

 

[midas]

//media.diynot.com/134000_133220_75356_64903551_thumb.jpg

It's a Memera 2000

Before the heating comes on tomorrow, I'll try the kettle then fan heater on the other ring circuit first before doing the same in the kitchen.

What I don't get is why if there is a fault does it seem to settle down after having a fit first thing in the morning?

BTW I took a look behind the suspect socket that may have water from the room above but I couldn't see anything obvious.

I can't be 100% certain that yesterday the trip was caused by my son plugging something in to that socket as it didn't trip straight away.

Oh well hopefully I can try and at least get closer to the source by trying various combinations


Thanks for all who are helping at the moment.

 

[Taylortwocities]

Your thumnail is too small to see what is what. It looks like you have an RCD as a main switch. Is that what is tripping?

Can you upload the picture to your image album and follow these instructions
//www.diynot.com/forums/viewtopic.php?t=129539
we then might have a chance of giving more guidance.
\
Thanks

 

[Aragorn84]

He did upload the pic to his album:

 

[Taylortwocities]

Aragorn, it doesnt display in your post. Lets see…..

Untitled

• midas
• 1 Apr 2014
• 1

Aah, that's better.

The basic problem is that the entire installation has just one RCD as the main switch. This is poor design because (as you have found out) one fault kills your entire house. It's a common sight, unfortunately.

It could be any one thing (ie a real fault) or it could be an accumulation of small niggles that on their own aren't enough to bother the RCD. Together, or a combination might be enough to trip the RCD.

There's two ways of sorting this:
1. Trial and error - the process that you have started on
or
2. Get an experienced electrician with an insulation resistance and RCD tester to go through every circuit and analyse what is causing the problem.

I really don';t think this can be solved through a PC screen on an Internet forum, beyond the advice given above.


EDIT; last thoughts. Have you isolated the immersion heater. They can be the cause of problems. Turn it off at the immersion itself and see (there should be a double pole switch there).

And. Those MCBS that are turned off. What are they connected to? If nothing then maybe there is redundant wiring still connected. This can cause problems even though the MCB is turned off as the neutral is still connected to the RCD...

 

[midas]

OK I think I'm getting closer...
I tried these steps at 6:00 a.m. before the central heating came on.
Firstly I tried the fan heater and the kettle together in the hall and it took about 1 minute to trip.
Trying the heater and kettle separately worked OK but tripped immediately if I tried both.
Any combination of both across any of the sockets from the kitchen or hall tripped immediately.
Also putting on too many rings on my electric cooker (separate circuit) also caused a trip.

It's now 9:a.m. and I am unable to get it to trip. I have two fan heaters the kettle and the cooking running, which is basically the same scenario as the previous two days.

Hopefully this extra info will help you experts narrow it down for me.

1. Why does it not trip immediately in the morning?
2. Why does it clear itself up as the day goes on?

I'm guessing maybe at the house heats up it temporarily solves my problem?

Many thanks for any help.