Advice on New Consumer Unit Change Please?

[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.

 

[vanessap]

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.

Hi @timhoward, Thank you! I had no idea that this existed, I imagine the extension in the kitchen area is where most of the work might be a bit iffy. I am not sure if it might have overload everything or caused damage but it would be really good to find out. Thank you, I will look into some quotes. Is it a lengthy process of testing?

 

[Cankeredlamentations]

Hi @timhoward, Thank you! I had no idea that this existed, I imagine the extension in the kitchen area is where most of the work might be a bit iffy. I am not sure if it might have overload everything or caused damage but it would be really good to find out. Thank you, I will look into some quotes. Is it a lengthy process of testing?

The time taking to test depends really on how many circuits there are and what shows up, for example an older installation (like my grandparents house) only has 6 circuits in total so testing those initially at the consumer unit and then at fixed equipment (light fittings, switches, shower etc) took me about 2 hours (I am still fairly new to the electrical trade) and there was no issues, although older wiring it still had good results as there had not been an alterations done on the original installation part from things like swapping light fittings. (I am sure a more experienced spark would be quicker than myself)

However the amount of time would increase when the test results indicate something is not correct or a fault (with a fault, It does not necessarily mean the circuit does not 'work' for the home owner but electrically it would not be to modern safety standards/regulations etc). In the case were the test results are not satisfactory, further testing is required, some tests may be more invasive than others depending on the situation and upon further testing it may be deemed that a rewire in full (as in all circuits) or a partial re wire (for example maybe 1 or 2 circuits need re wiring).

some faults are easier to investigate than others but it is dependant on the circumstances, you may have the same type of issue in one property that is easy to resolve and find the route cause, while in another its an absolute nightmare because of how the wiring is routed (old nasty lofts full of junk, insulation and joint boxes are a particular favourite of most electricians lol).

A full EICR will be able to check for this and the person doing should outline any remedial work required.

 

[Vortigern]

When you say the consumer unit is "not finished" what do you mean exactly?

 

[vanessap]

Thank you all so much!

I meant it was not finished in that I now understand that the electricians did not test the electrics before replacing the consumer unit, at the end when they finished I was told that they needed to come back to do a bit more testing but I believe they knew that there was a fault and were possibly avoiding having to address it or figure it out. They have withheld giving a completion certificate or building regulations certificate at my home; this work was done in Dec 2021. They have now said that they would not offer a quote to find the issue as their minimum call out fee per days work is £1000.00 though they will come back to complete the testing and give a certificate once the fault is resolved by someone else.

 

[nicebutdim]

Was this put in writing?

More words to meet daft forum requirement.