Potential boiler issue

[JP0704]

Calling all electrical professionals / boiler tradesmen -WE NEED YOUR HELP!

Every so often (twice in the last two days) when running the hot water in the kitchen it trips our electrics (downstairs lights, sockets, cooker and boiler) and cannot be reset for a good 20-30 mins. This only happens randomly and when running the hot water. We have unplugged all appliances except cooker and it still happened. We have had an electrician out who said all is good (EICR done in July 2023 and all good) and had plumber out to service boiler and also run through cycles of high fire and low fire with no issues (this was completed during the daytime,
Not evening).
We have had the water pressure sensor changed but no change to trips.
When having a shower in the evening it has not tripped the electrics, it only seems to be when using the kitchen hot water.
Any advice greatly appreciated.
Thanks
Jon

 

[James]

It is good news that you have an all RCBO board, that should help the electrician narrow down the fault.

 

[DefyG]

Circuits 4 and 12 both labelled 'Kitchen Sockets' on 16A MCB's so does look like the circuit has been split with the fault on circuit 12 side.

 

[JP0704]

Circuits 4 and 12 both labelled 'Kitchen Sockets' on 16A MCB's so does look like the circuit has been split with the fault on circuit 12 side.

Yes but I intentially tripped no4 and it didn’t kill any kitchen sockets?

 

[JP0704]

It is good news that you have an all RCBO board, that should help the electrician narrow down the fault.

Yes to the kitchen sockets. No further as of yet.
You know any decent fault Finding electricians in Cambridgeshire area

 

[Yellowhammer]

Never know, if you let Artisan electrics do it on YT you might get it for free

Edit: It should be getting a fair bit simpler to solve at this point though, limited to a number of sockets, and therefore cables.

 

[JP0704]

Yes to the kitchen sockets. No further as of yet.
You know any decent fault Finding electricians in Cambridgeshire area

Never know, if you let Artisan electrics do it on YT you might get it for free

Edit: It should be getting a fair bit simpler to solve at this point though, limited to a number of sockets, and therefore cables.

We did initially think of them for our EICR but they were EXPENSIVE!
Always tempted by a freebie but not sure about my house featuring on YT if I’m honest.

 

[DefyG]

Yes but I intentially tripped no4 and it didn’t kill any kitchen sockets?

So the whole kitchen (sockets) is on a 16A radial circuit?

Can you tell if the cables and pipework come into contact with one another at some point?

Hot water is just pressurised or gravity? No pump or heater involved?

Perhaps unplug every appliance on that circuit and see if it still trips but I'm sure the other sparks have tried that.

Being an intermittent fault it will be or can be difficult to locate.

 

[DefyG]

What insulation resistance does the certificate show for that circuit(12)

 

[JP0704]

What insulation resistance does the certificate show for that circuit(12)

It was only put in yesterday. Not when they installed the board.

 

[JP0704]

So the whole kitchen (sockets) is on a 16A radial circuit?

Can you tell if the cables and pipework come into contact with one another at some point?

Hot water is just pressurised or gravity? No pump or heater involved?

Perhaps unplug every appliance on that circuit and see if it still trips but I'm sure the other sparks have tried that.

Being an intermittent fault it will be or can be difficult to locate.

I believe yes. I think they downgraded it from 32amp?

The hot water is from a combi boiler.
Can’t see any issues to the eye with wires etc.

 

[Yellowhammer]

The electrician needs to come in the evening when you are able to recreate the fault. Assuming it is consistent in the evenings with the kitchen hot water on. It should be fairly easy to narrow down the item/leg of the radial causing the issue with an mft if the fault remains for 20mins or so at a time.

 

[DefyG]

It was only put in yesterday. Not when they installed the board.

What was only just been put in, the mcb if not the board? When was the new board installed? and you dont have a test certificate yet?

Seems naive of you and the electrician to think a new board would solve the tripping fault.
Being on a separate RCBO will help minimise the inconvenience though and help locate it but you had already established it was the kitchen socket circuit.?

 

[JP0704]

What was only just been put in, the mcb if not the board? When was the new board installed? and you dont have a test certificate yet?

Seems naive of you and the electrician to think a new board would solve the tripping fault.
Being on a separate RCBO will help minimise the inconvenience though and help locate it but you had already established it was the kitchen socket circuit.?

The RCB was only just put in.
The board was last week and yes we have the cert already.

The new board was not only because of the tripping but because the other was very old.
We couldn’t narrow it down before as it tripped the whole bank.