Electrical Circuit Tripping

[Greenmantle]

I have two consumer units. Each has about 10 RCB circuit breakers.
Bottom does sockets.
Top does lights and ancillaries.

The bottom one tripped 3 times yesterday and once today. None of the individual RCB breakers were tripped just the main unit switch.

The things that were plugged in and switched on were:
broadband router, network switches x 3 and wireless access points x2
laptops x 2, floor standing fans x2,
American fridge freezer, cooker range (not being used), smart meter monitor, Myzappi car charger (not being used).

I originally thought it was one of the fans since this issue only started last two days but now I am thinking it maybe the fridge freezer start relay.
Does anyone have any suggestions?

[119]

Freddie freezer wound be my guess.

Probably been working overtime these last few days!

[dhutch]

Greenmantle said:

I have two consumer units. Each has about 10 RCB circuit breakers.
Bottom does sockets.
Top does lights and ancillaries.

The bottom one tripped 3 times yesterday and once today. None of the individual RCB breakers were tripped just the main unit switch.

The things that were plugged in and switched on were:
broadband router, network switches x 3 and wireless access points x2
laptops x 2, floor standing fans x2,
American fridge freezer, cooker range (not being used), smart meter monitor, Myzappi car charger (not being used).

I originally thought it was one of the fans since this issue only started last two days but now I am thinking it maybe the fridge freezer start relay.
Does anyone have any suggestions?

Presumably the 'main switch' is an RCD, hence likely a fault to earth somewhere.
Slightly odd to have sockets on one, lights on the other, usually you would have half and half for better diversity/redundancy.

First thing to mention is unplugged is different to switched off, as typically the switch isnt only on the live and it could be a fault to neutral.
Second things that will get mentioned is the refrigerators are one of the key things than cant develop earth leakage faults, so dont rule that out.
Its currently dryish in most places, but if you have outdoor sockets or lights, maybe running a pond pump or something, thats another key one.
Spark ignitors on gas hobs are also not uncommon, the button fails, hob gets washed, etc. Or else ours just randomly trips always, we use a gas match now!

But otherwise its just a case of unplugging things and seeing if it stops, and or switching whole circuits off at the MCB and trying that, one of the reasons its a shame you dont have some sockets on the other board/RCD.. Although again the MCB is only on the live, you may or may not be comfortable taking the front off the consumer unit and pulling the circuits neutral wires out but thats the next step.

The other option is to get some RCBOs, if you board can take them, which gives circuits their own RCD protection and hence can narrow down the trip.

[Greenmantle]

Thanks for both replies. A fault to earth is highly likely. The house is 25 years old and I have lived in it all that time. The electrics have been rock solid.
Since my OP I have been just keeping a note of the time and date of each trip.
It averages out to 2 / 3 trips per day.
At one point I was convinced it was something external going on (at the substation) since I recorded three consecutive trips at 00:20.
I have scrubbed that one out now.
Anyway, last night I turned off all the circuits apart from 3 (kitchen, my bedroom and loft / alarm). It still tripped but at 04:30.
I'm going to price up swapping all circuits for RCBOs since I can do that myself (big switch at meter box will be OFF when I do this).
The leading culprit is still the American fridge / freezer which I will be able to shutdown next week and move contents to the half fridge that I don't use.
Hopefully I will have an update by Wednesday.

[eliot]

Greenmantle said:

I'm going to price up swapping all circuits for RCBOs since I can do that myself .

Changing the MCB's for RCBO's on an RCD fed consumer is wrong and I assume you aren't a qualfied spark.

If it's 25 years old - get the whole thing replaced with a regs compliant metal consumer unit with per circuit RCBO's and a surge protection (which of course you should use a spark for)

[Mr Pointy]

Greenmantle said:

Thanks for both replies. A fault to earth is highly likely. The house is 25 years old and I have lived in it all that time. The electrics have been rock solid.
Since my OP I have been just keeping a note of the time and date of each trip.
It averages out to 2 / 3 trips per day.
At one point I was convinced it was something external going on (at the substation) since I recorded three consecutive trips at 00:20.
I have scrubbed that one out now.
Anyway, last night I turned off all the circuits apart from 3 (kitchen, my bedroom and loft / alarm). It still tripped but at 04:30.
I'm going to price up swapping all circuits for RCBOs since I can do that myself (big switch at meter box will be OFF when I do this).
The leading culprit is still the American fridge / freezer which I will be able to shutdown next week and move contents to the half fridge that I don't use.
Hopefully I will have an update by Wednesday.

The fridge/freezer contents should be fine over night if you don't open the door so you could turn it off for 8 hours or so & see if you get tripping or not.

[TwistingMyMelon]

ANything with water would be my first port of call so Fridge Freezer...

[dhutch]

Mr Pointy said:

The fridge/freezer contents should be fine over night if you don't open the door so you could turn it off for 8 hours or so & see if you get tripping or not.

This is true. Especially if you have some coolbox blocks in the top drawer. And unplug it, don't just turn it off.

As said, shame there isn't a sockets circuit off the other board/rcd.

[Belle427]

Fridge freezer would be my first thought, the defrost cycle which can happen at odd times is the favourite as it incorporates a heating element.
Very hard to pin down.

[Spare tyre]

With extension leads swap the fridge freezers to a different circuit and see if that trips

I find generally things with motors / compressors are culprits

[Spare tyre]

Mr Pointy said:

Greenmantle said:

Thanks for both replies. A fault to earth is highly likely. The house is 25 years old and I have lived in it all that time. The electrics have been rock solid.
Since my OP I have been just keeping a note of the time and date of each trip.
It averages out to 2 / 3 trips per day.
At one point I was convinced it was something external going on (at the substation) since I recorded three consecutive trips at 00:20.
I have scrubbed that one out now.
Anyway, last night I turned off all the circuits apart from 3 (kitchen, my bedroom and loft / alarm). It still tripped but at 04:30.
I'm going to price up swapping all circuits for RCBOs since I can do that myself (big switch at meter box will be OFF when I do this).
The leading culprit is still the American fridge / freezer which I will be able to shutdown next week and move contents to the half fridge that I don't use.
Hopefully I will have an update by Wednesday.

The fridge/freezer contents should be fine over night if you don't open the door so you could turn it off for 8 hours or so & see if you get tripping or not.

Also if you are concerned about the freezer, save up some spare coke bottles etc and turn them into size block. Once they are initially frozen they are going to buy you more time

[finlo]

Spare tyre said:

With extension leads swap the fridge freezers to a different circuit and see if that trips

I find generally things with motors / compressors are culprits

Won't work as the RCD covers all circuits.

[Spare tyre]

finlo said:

Spare tyre said:

With extension leads swap the fridge freezers to a different circuit and see if that trips

I find generally things with motors / compressors are culprits

Won't work as the RCD covers all circuits.

Bugger, ask a neighbour if they have a circuit you could use, hmm that’s probably not gonna go down well

[Panamax]

Spare tyre said:

With extension leads swap the fridge freezers to a different circuit and see if that trips

I find generally things with motors / compressors are culprits

All makes good sense.

Toasters and irons also love to trip breakers, but fairly obviously you know when they are in use. It's fridges that do their own thing switching motors on and off automatically.

[Greenmantle]

Afternoon

So the culprit was the Fridge Freezer.
I opened up the bottom compartment at the back (compressor, fans, drip trays).
Not nice looking - trays were full and gunky. I was quite ashamed since I pride myself on house work.
Anyway, I am going to give it a good clean.
Just watched some videos saying it maybe the defrost element absorbing moisture which hopefully now it won't do since the trays are dry.
After the clean I plan to switch it on for 24 hrs and see what happens.
Thanks for all your responses.

[dhutch]

Greenmantle said:

Afternoon

So the culprit was the Fridge Freezer.
I opened up the bottom compartment at the back (compressor, fans, drip trays).
Not nice looking - trays were full and gunky. I was quite ashamed since I pride myself on house work.
Anyway, I am going to give it a good clean.
Just watched some videos saying it maybe the defrost element absorbing moisture which hopefully now it won't do since the trays are dry.
After the clean I plan to switch it on for 24 hrs and see what happens.
Thanks for all your responses.

Good work.

Its pretty status normal for the condensation tray to gunky as hell. Hopefully the fridge freezer pulls through!

[Sheepshanks]

Greenmantle said:

Afternoon

So the culprit was the Fridge Freezer.
I opened up the bottom compartment at the back (compressor, fans, drip trays).
Not nice looking - trays were full and gunky. I was quite ashamed since I pride myself on house work.
Anyway, I am going to give it a good clean.
Just watched some videos saying it maybe the defrost element absorbing moisture which hopefully now it won't do since the trays are dry.
After the clean I plan to switch it on for 24 hrs and see what happens.
Thanks for all your responses.

We had a proper old American Maytag side-by-side and a couple of times in the 20yrs we had it the drip tray at the bottom of the freezer evaporator froze and overflowed into the bottom of the freezer. It's really not trivial to get at it - access is from inside the freezer - so it's not meant to be customer serviceable.

We left is unused for about 5 months while our house was being refurbed and it went horrendously mouldy inside. Wife and I spend 4hrs taking everything apart and cleaning it. It ran for about 6hrs then tripped the new RCBO. I found the defrost heater was leaking to earth. Would probably have got away with it with an MCB (or rewireable fuse, as there was before the refurb).

Anyway, it was on my mind there would still be mould in the airflow channels etc and it didn't really fit in with the newly refurbed house, so we bought a new one.

[119]

Greenmantle said:

Afternoon

So the culprit was the Fridge Freezer.
I opened up the bottom compartment at the back (compressor, fans, drip trays).
Not nice looking - trays were full and gunky. I was quite ashamed since I pride myself on house work.
Anyway, I am going to give it a good clean.
Just watched some videos saying it maybe the defrost element absorbing moisture which hopefully now it won't do since the trays are dry.
After the clean I plan to switch it on for 24 hrs and see what happens.
Thanks for all your responses.

You’re welcome.

£10 to a charity of your choice.