Intermittent RCD tripping. Benefit of changing over to RCBO's?

[mc1903]

Hi,

We have recently had some electrical work completed in the house to add a new circuit for air conditioning.

We are now experiencing intermittent RCD trips, at all hours of the day and night, in the section of the consumer unit that the new A/C MCB was installed into.

No MCB's trip - just the common RCD.

I have a non-electrical technical background and understand that fault finding intermittent issues is usually a complete nightmare. I work from home and I am losing money/reputation each time the RCD trips and I get kicked out of a client call.

I am after professional opinion on the actual benefit of changing out all of the MCB's/RCD's for RCBO's and, if there is a real benefit, what a fair ball park cost & hours/days to complete would be? What 'paperwork' should I ask for/expect as part of any remedial electrical works, to cover me from a home insurance position?

Picture of consumer unit attached.

Thanks in advance.
M

 

[SJD]

Somewhat odd to have all the lighting on one RCD, and all the sockets on the other - normally they would be divided across each RCD to minimise inconvenience in the event of a trip.

I was going to say in the meantime make sure critical items like internet router are plugged into sockets on the non-tripping RCD, but of course you can't do that due to the way the board has been installed.

 

[UNG]

If the CU can be reconfigured just add an RCBO for the A/C and may be reconfigure / swap around some of the circuits to give a better split across the 2 RCD's

 

[mc1903]

Somewhat odd to have all the lighting on one RCD, and all the sockets on the other - normally they would be divided across each RCD to minimise inconvenience in the event of a trip.

I was going to say in the meantime make sure critical items like internet router are plugged into sockets on the non-tripping RCD, but of course you can't do that due to the way the board has been installed.

? Lol... we thank George Wimpey almost everyday for something else we find wrong with our house.

GW only seem to care to minimise inconvenience to themselves during the build; the punter (me) is a secondary consideration!

Any thoughts on RCBO's?

Cheers
M

 

[SJD]

As mentioned by UNG, simplest option is likely swap circuits around, and just put anything critical or problematic on its' own RCD, if the board can be configured to do that. A complete board change with all RCBOs like to cost £600 to £1000 or more, depending on brand, your location and how expensive a quote you get.

 

[mc1903]

If the CU can be reconfigured just add an RCBO for the A/C and may be reconfigure / swap around some of the circuits to give a better split across the 2 RCD's

So could I have a mix of MCB's/RCD's and RCBO's in the same CU?

In a professionally installed CU, should there usually be enough length on the various wires to move things around?

I use the word professional cautiously in respect of the house builder ??

Thanks
M

 

[mc1903]

As mentioned by UNG, simplest option is likely swap circuits around, and just put anything critical or problematic on its' own RCD, if the board can be configured to do that. A complete board change with all RCBOs like to cost £600 to £1000 or more, depending on brand, your location and how expensive a quote you get.

Thank you both @SJD & @UNG - £600-£1000 seems a bargain if it solves or at least narrows down where the issue is. I have spent about 15x that on A/C that I now have isolated to see if it IS the issue.

 

[UNG]

Thank you both @SJD & @UNG - £600-£1000 seems a bargain if it solves or at least narrows down where the issue is. I have spent about 15x that on A/C that I now have isolated to see if it IS the issue.

The £600 - £1000 would be for a complete consumer unit swap a bit of reconfiguring of the existing unit would be likely to cost no more than £250

 

[mc1903]

The £600 - £1000 would be for a complete consumer unit swap a bit of reconfiguring of the existing unit would be likely to cost no more than £250

Thank you @UNG

 

[littlespark]

There can be many reasons why rcd’s trip out, and having all the sockets on the one rcd will cause trouble.

a small earth leakage on anything from the fridge compressor to a number of phone chargers etc may not be a problem on their own, but added together could exceed the 30mA threshold.

simplest thing to try first is swap a few circuits between sides and see if that sorts things.

It’s not a DIY job though....

 

[mc1903]

There can be many reasons why rcd’s trip out, and having all the sockets on the one rcd will cause trouble.

a small earth leakage on anything from the fridge compressor to a number of phone chargers etc may not be a problem on their own, but added together could exceed the 30mA threshold.

simplest thing to try first is swap a few circuits between sides and see if that sorts things.

It’s not a DIY job though....

Thank you @littlespark

The current configuration of the CU was down to the builder/their electrical contractor. House was built in 2007, I assume the way things are done now is different from back then; but even so, putting all sockets on one RCD seems daft, now that I understand it a little more.

I have had a quote to completely replace the CU with "1 x 18th edition 14 way consumer unit with individual RCBO protection" and it is close to the top end of the estimate range @SJD gave earlier.

I am waiting on another company to visit and give me their advice, but rest assured I will be going nowhere near the CU with tools myself. I know my limits. ?

 

[UNG]

The current configuration of the CU was down to the builder/their electrical contractor. House was built in 2007, I assume the way things are done now is different from back then; but even so, putting all sockets on one RCD seems daft, now that I understand it a little more.

The way it should have been done hasn't changed at all and is no different now to how it was back in 2007

 

[littlespark]

The way it should have been done hasn't changed at all and is no different now to how it was back in 2007

So basically it wasn’t done right in the first place.

It’s not hard to realise that the loads should be shared between the two rcd’s....

We try to aim for sockets and lights in the same room on different sides.... kitchen sockets and cooker on different sides. Upstairs/ downstairs on different sides....
It’s not always possible, but should be separated as much as possible.

 

[brianmoooore]

We try to aim for sockets and lights in the same room on different sides.... kitchen sockets and cooker on different sides. Upstairs/ downstairs on different sides....
It’s not always possible, but should be separated as much as possible.

Exactly how I've always tried to arrange it. A RCBO board will solve the problem, but it's a bit of a sledge hammer to crack a nut, and won't, in itself, deal with the fault
George Wimpy almost certainly paid peanuts, and you know what that gets you...

 

[littlespark]

George Wimpy almost certainly paid peanuts, and you know what that gets you...

A wet pants with a nut allergy??? ?