Advice on New Consumer Unit Change Please?

[vanessap]

Hi Everyone,

Last year arranged for my mother's and my consumer units to be changed by the same electrician who is NICEIC registered.

Both jobs were not completed for various reasons, I have been trying to arrange for them to be completed over the last two months. At my home the oven began tripping after the unit was changed, which has not been resolved and I have since learned from a local TLC electrical shop that grounding wires should have been attached to the water mains stopcock (I have purchased the cable, attachment and our plumber has attached to so it can be run and attached).

The electrician who has now agreed after much chasing, to visit my mother's home on Friday to complete the work, though he has said that he will have to charge extra for testing and the certificate. I have paid £750.00 for the labor on each unit and parts separately, which I understood was for the entire job last year. The TLC electrical shop also explained that testing should be done before and after the installation.

Please may I ask if anyone might be able to shed some light on the process of installing a new consumer unit and what the job usually entails please, so I may have some idea if the work is being carried out correctly and safely?

Thank you so much in advance,
Vanessa

 

[westward10]

Most people will carry out a modicum of testing prior to the change to see if there are any issues which may affect the change. You should not be charged for testing and Certification that is part of the job.

 

[DefyG]

Testing, certification and Building Reg (Part P) notification is in my mind all part of the job.

Equally earth bonding is part of the job as it can not be signed off without earthing/bonding meeting regulations at the time.

 

[littlespark]

If everything is now rcd protected, bonding isn’t such of an issue. Plastic pipes perhaps.
Remember TLC is a shop, not an electrician.

 

[Cankeredlamentations]

Agree with what the others before me have said, before changing a consumer unit, normally you would do testing on the existing wiring to see if there are any issues that need resolving before changing the consumer unit that may cause tripping on a new modern consumer unit (but not necessarily on an existing unit). If the unit has been changed without testing and you start getting tripping issues, then in my mind you in a difficult situation (as an installer) as you would then need to identify the issue, the fix required etc and the additional costs, where as if these are identified beforehand, you're are better placed to explain to the customer what it is and any additional costs involved prior to the board change. Bonding should have been done either way if it was missing and a EIC, though I would have thought if things are tripping now, they may have been minimal testing potentially (which would have highlighted any issues on the existing wiring ) when the board was replaced? Potentially could be a faulty appliance that is connected or other issues like borrowed neutrals etc.

 

[davesparks]

I have since learned from a local TLC electrical shop that grounding wires should have been attached to the water mains stopcock (I have purchased the cable, attachment and our plumber has attached to so it can be run and attached).

Not necessarily, unless the person who advised you about this has actually looked at the installation and tested it then they can't possibly know for sure whether earth bonding is requires or not.

The electrician who has now agreed after much chasing, to visit my mother's home on Friday to complete the work, though he has said that he will have to charge extra for testing and the certificate.

Testing and certification is a fundamental part of any electrical work and should have been done as part of the job.

 

[vanessap]

Thank you so much for you response @westward10 @DefyG @littlespark @Cankeredlamentations and @davesparks

I am not sure how much testing was done at my home, which is where the oven began tripping a few hours after the consumer unit was changed. I remember the engineer saying that he had quite an expensive plug in machine which he used for testing.

Could I ask if it is complicated to test if the oven might be faulty and to maybe disconnect it to leave everything safe please?

With the earthing / bonding the engineer mentioned that it was something that he needed to do at my mum's house. To complete the installation. Everything has worked very well at my mum's house since the unit was installed. Its more so that I thought everything was completed and then he mentioned earthing and testing, which is why I am trying to understand the process of a the installation of a new consumer unit a bit more.

Thank you for answering all of my questions, I am think I am a bit nervous as the same family run company replaced our boilers at the same time and I am also chasing paperwork for them as well. The plumbing feels a bit more straightforward, though the electrics have been a bit confusing as he has made a few ambiguous comments about testing and fees.

Thank you all so much,
Vanessa

 

[Ffeadam]

Thank you so much for you response @westward10 @DefyG @littlespark @Cankeredlamentations and @davesparks

I am not sure how much testing was done at my home, which is where the oven began tripping a few hours after the consumer unit was changed. I remember the engineer saying that he had quite an expensive plug in machine which he used for testing.

Could I ask if it is complicated to test if the oven might be faulty and to maybe disconnect it to leave everything safe please?

With the earthing / bonding the engineer mentioned that it was something that he needed to do at my mum's house. To complete the installation. Everything has worked very well at my mum's house since the unit was installed. Its more so that I thought everything was completed and then he mentioned earthing and testing, which is why I am trying to understand the process of a the installation of a new consumer unit a bit more.

Thank you for answering all of my questions, I am think I am a bit nervous as the same family run company replaced our boilers at the same time and I am also chasing paperwork for them as well. The plumbing feels a bit more straightforward, though the electrics have been a bit confusing as he has made a few ambiguous comments about testing and fees.

Thank you all so much,
Vanessa

Hi Vanessa,

There are tests that can be undertaken on the oven/appliance. The difficulty would be gaining access to the connections (how hidden they may be/awkward). If the appliance passes these initial tests then a further test can be done to measure earth leakage once under load and upto temperature. These are above and beyond what would be undertaken on a simple consumer unit change.

However regardless of this nuisance tripping a certificate should have been provided upon completion. As others have stated the main protective bonding conductors to the incoming water and gas services would need to be assessed when undertaking any electrical works.

 

[DefyG]

Could I ask if it is complicated to test if the oven might be faulty and to maybe disconnect it to leave everything safe please?

Its most likely just a coincidence that the oven circuit 'trips', and if left 'off' it wont be any less safe for the other circuits. You could also isolate the oven on its local isolator (assuming the is one) without affecting the rest of the installation.
Curious to know how long was spent replacing the consumer unit without any testing or earthing for £750, as most competent sparks could replace a 20module board alone in less than half a day!

 

[vanessap]

Hi @Ffeadam and @DefyG thank you both for your response!

If the Oven was completely disconnected would that help matters. It is quite an old oven, it is very possible it could be faulty. I am trying to think of suggestions to speed up the completion of the consumer unit, as I have not yet received a certificate for it and thought to suggest that they just disconnect the oven.

My aim is to replace the kitchen in the coming months and strip the house. Whilst doing this I thought it might be and idea to renew the electrics, though I am not sure if it is necessary. Do you recommend stripping back all wiring in old houses, or would it depend on testing please?

In terms of the consumer unit installation, it took one full day for the engineer and his brother who assisted him.

Many thanks,
Vanessa

 

[timhoward]

I am not sure how much testing was done at my home, which is where the oven began tripping a few hours after the consumer unit was changed.

It's possible that the the oven didn't have RCD (earth leakage) protection in the old consumer unit and always had a minor fault.
Whether the minor fault would show up under a typical round of pre-board change testing depends on several things and it's not a given that it would show up.
My best guess is that one of the oven elements was always slightly faulty and the new consumer unit notices the electricity going the wrong way and the safety device operates.

I think you need to treat this as two topics.
1) Get your consumer unit job finished including testing and certification.
2) Find another electrician to look into your oven fault. I can normally diagnose an oven problem within an hour, 2 at the most.

The oven shouldn't prevent the CU job being finished unless the fault is on the wiring between the consumer unit and the isolator switch in the kitchen.

EDITED to add - I recently did an inspection where the oven circuit had poor results. I turned the isolator off in the kitchen. The results reverted to near perfect. The fixed wiring was fine, and it didn't affect the report, other than a verbal comment to the prospective house-holder that the oven has a fault.

 

[timhoward]

My aim is to replace the kitchen in the coming months and strip the house. Whilst doing this I thought it might be and idea to renew the electrics, though I am not sure if it is necessary. Do you recommend stripping back all wiring in old houses, or would it depend on testing please?

Yes, in short that depends entirely on inspection and testing. What the cables are made of, how much they have been messed around with since original installation, and test results all contribute to this sort of decision.

 

[vanessap]

It's possible that the the oven didn't have RCD (earth leakage) protection in the old consumer unit and always had a minor fault.
Whether the minor fault would show up under a typical round of pre-board change testing depends on several things and it's not a given that it would show up.
My best guess is that one of the oven elements was always slightly faulty and the new consumer unit notices the electricity going the wrong way and the safety device operates.

I think you need to treat this as two topics.
1) Get your consumer unit job finished including testing and certification.
2) Find another electrician to look into your oven fault. I can normally diagnose an oven problem within an hour, 2 at the most.

The oven shouldn't prevent the CU job being finished unless the fault is on the wiring between the consumer unit and the isolator switch in the kitchen.

EDITED to add - I recently did an inspection where the oven circuit had poor results. I turned the isolator off in the kitchen. The results reverted to near perfect. The fixed wiring was fine, and it didn't affect the report, other than a verbal comment to the prospective house-holder that the oven has a fault.

Hi @timhoward,

Thank you so much! This helps a lot, I think the electrician who changed the consumer unit is just overly busy which is why I am apprehensive about asking for him to complete more work.

Thank you so much, I will definitely suggest this to him. I will also seek out some quotes for testing.

Many thanks,
Vanessa

 

[vanessap]

Yes, in short that depends entirely on inspection and testing. What the cables are made of, how much they have been messed around with since original installation, and test results all contribute to this sort of decision.

Hi @timhoward,

Sorry if this is a ridiculous question, is this something that the the consumer units tests might be able to highlight or is there another specific test that would be best for me to look into to test the health of the wiring please? I think my parents might have rewired the house forty years ago.

Many many thanks,
Vanessa

 

[timhoward]

Hi @timhoward,

Sorry if this is a ridiculous question, is this something that the the consumer units tests might be able to highlight or is there another specific test that would be best for me to look into to test the health of the wiring please? I think my parents might have rewired the house forty years ago.

Many many thanks,
Vanessa

Not a silly question.
What you want is a thing called an EICR - an electrical installation condition report.
The testing part of this has things in common with the testing done after a consumer unit change, but an ECIR is also an inspection which is trying to discover as much as possible about the condition of the wiring and things that have happened to it and whether it is deemed satisfactory for continued use.

I'd generally expect PVC wiring from the 80's to be in serviceable condition IF it hasn't been overly subjected to DIY, cowboy electricians, kitchen fitters, water ingress, been overloaded, etc.
There may be a shortage of sockets relative to what would be useful today, but that is a separate issue.