Is new cu required for new oven install?

[Spoon]

He said something about old being 40 and new only being 20. Both are hard wired but the position isn't changing. He said the new one would burn out due to the difference...images attached.

So the old cooker is connected to a 40A breaker and the new one only needs a 20A breaker.?? Is this correct?

I'd consider getting another electrician in to quote for the job...
Maybe there is an electrician on the forum that lives near you (High Wycombe) that could give you a quote.

 

[spynage]

An electrician has recently quoted to replace our old oven. He says that the new oven has different power requirements and he needs to replace the consumer unit to make this lower and avoid burning out our new oven within weeks! The cu was new in 2015 so I am concerned that it now needs replacing - this will cost double the cost of the oven... Help please!

BS. The appliance draws power it's not pushed into it! Totally fraudulent to suggest what he is saying. If it's lower power fine just connect up the new oven. BTW. Its worth checking if he is a registered electrician and wether he has a CPS no. Find out and notify his competent persons scheme, NAPIT, NICEIC etc. Let them know what he is up to.

 

[Vortigern]

I am very sorry, but it seems like you are being conned here. Please try another electrician. And the above I echo thoroughly!

 

[Julie.]

An electrician has recently quoted to replace our old oven. He says that the new oven has different power requirements and he needs to replace the consumer unit to make this lower and avoid burning out our new oven within weeks! The cu was new in 2015 so I am concerned that it now needs replacing - this will cost double the cost of the oven... Help please!

He's either lying or totally incompetent!

If the new oven is only 20A than the MAXIMUM it can draw is 20A.

It doesn't matter that the supply is suitable for up to 40A, the oven can only draw up to 20A .

This is pretty basic stuff for an electrician!

So, regulations:
Since the oven is known as a fixed load in electrical terms, the existing 40A supply can remain as is without the need to change it - merely connect the new oven. (Although if I had a suitable smaller MCB closer to 20A I would probably change it - but it isn't mandatory)

However, it may be the case that your existing installation doesn't have RCDs (although given the age it should) in which case it should be upgraded - for more than the oven!)

Do you have a photo of the board?

 

[davesparks]

He said something about old being 40 and new only being 20. Both are hard wired but the position isn't changing. He said the new one would burn out due to the difference.

OK, it sounds like you have an oven circuit which is currently protected by a 40A MCB and the new oven probably requires a 20A supply, this is likely to be specified in the manufacturers instructions.

Connecting the new oven to the existing 40A supply will not cause it to burn out, this is just not possible.
It is possible that the electrician who has told you this simply doesn't understand the basic science of electricity and genuinely believes that what they are saying is true (this is true for a scary number of people trading as electricians these days) or else they are outright trying to scam you.

Whilst technically it is acceptable to connect the new oven to the existing supply as-is there may be advantages to changing the 40A circuit breaker to a 20A one, but this would not require the whole CU (fusebox) to be replaced! It would only require the one circuit breaker to be replaced, even if it is not RCD protected currently then a circuit breaker which incorporates RCD protection, called an RCBO, could be fitted.


However if there is a genuine reason to advise replacing the CU then any decent electrician would explain this properly along with explaining what the improvent would be and why you might need them.

 

[James]

Echoing the sentiment of most posts above, i think we can agree in summary that it is the electrician that needs replacing, not the distribution board.

following the absurd explanation about a 40A supply burning out a 20A oven in weeks, its incredible that we have all survived the change to led "light bulbs" as they generally use about 90% of the power. so an original 6A lighting circuit should be burning out the new lights within minutes!!

 

[Jules123]

Apparently the old oven was higher than the new Hotpoint DKD3 841 IX one. He said something about old being 40 and new only being 20. Both are hard wired but the position isn't changing. He said the new one would burn out due to the difference...images attached.

 

[Jules123]

So the old cooker is connected to a 40A breaker and the new one only needs a 20A breaker.?? Is this correct?

I'd consider getting another electrician in to quote for the job...
Maybe there is an electrician on the forum that lives near you (High Wycombe) that could give you a quote.

Thanks for replies everyone. Looks like we need to keep looking for an electrician! Had two quote so far and need someone for some kitchen electrics as cowboy kitchen fitters had to be let-go. They were damaging the units! Dream kitchen not going so well atm

 

[Jules123]

He's either lying or totally incompetent!

If the new oven is only 20A than the MAXIMUM it can draw is 20A.

It doesn't matter that the supply is suitable for up to 40A, the oven can only draw up to 20A .

This is pretty basic stuff for an electrician!

So, regulations:
Since the oven is known as a fixed load in electrical terms, the existing 40A supply can remain as is without the need to change it - merely connect the new oven. (Although if I had a suitable smaller MCB closer to 20A I would probably change it - but it isn't mandatory)

However, it may be the case that your existing installation doesn't have RCDs (although given the age it should) in which case it should be upgraded - for more than the oven!)

Do you have a photo of the board?

Thanks for replies everyone. Looks like we need to keep looking for an electrician! Had two quote so far and need someone for some kitchen electrics as cowboy kitchen fitters had to be let-go. They were damaging the units! Dream kitchen not going so well atm

He said it only had one rcd??

 

[James]

View attachment 106475

He said it only had one rcd??

I count two RCD's and i have had 3 beers.
what was he drinking???

 

[Jules123]

Don't think your images worked. Copy and paste works well on this forum for images by the way.

Even if not RCD protected I'd still change a broken appliance.
New oven is 4.7Kw. A 'standard' 6 sq mm cable and B32 cooker circuit would be fine. Subject to seeing pictures, it sounds like you should find a different electrician.

 

[brianmoooore]

Could be manufacturer's instructions stating maximum fusing of 20A, but B20 Europa MCBs are readily available and cheap.

 

[davesparks]

View attachment 106475

He said it only had one rcd??

There are 2 RCDs in that unit, they are the two devices labelled as RCCB.

Whilst I tried to give some benefit of the doubt earlier I would say this confirms you have been outright lied to.

I see no reason why that 40A MCB couldn't simply be swapped for a 20A MCB if that is required, those MCB's are current and still available.

There may be some mention of that CU being plastic when these days we are required to fit metal ones, but that would not prevent the work as you have described it from being carried out.

 

[Jules123]

I count two RCD's and i have had 3 beers.
what was he drinking???

I am having the worse time with incompetent traders atm so glad you guys have all taken the time to tell me what's what. Thought it was bizarre that a replacement oven was such a problem!...

 

[Jules123]

There are 2 RCDs in that unit, they are the two devices labelled as RCCB.

Whilst I tried to give some benefit of the doubt earlier I would say this confirms you have been outright lied to.

I see no reason why that 40A MCB couldn't simply be swapped for a 20A MCB if that is required, those MCB's are current and still available.

There may be some mention of that CU being plastic when these days we are required to fit metal ones, but that would not prevent the work as you have described it from

I am having the worse time with incompetent traders atm so glad you guys have all taken the time to tell me what's what. Thought it was bizarre that a replacement oven was such a problem!...

 

[Julie.]

View attachment 106475

He said it only had one rcd??

Nothing wrong with that consumer unit. (ish)

It has two RCDs!

He can't even count.

You could get the 40A MCB changed to a 20A or 25A, they are available if you want.


Now, it is the case that that consumer unit does not meet current standards, but in itself that doesn't mean it has to be changed.

If there is any sign of heat damage and/or a couple of other things, then it should be changed.

But from your photos, there is no evidence that a change is mandatory.

 

[brianmoooore]

The rules have changed since your CU was installed. Yours is plastic, and only steel ones can be fitted in domestic properties now, but the rules aren't retrospective, so as long as individual parts are available for it (which they are) it doesn't need to be changed.

 

[Jules123]

Thanks so much everyone - this has been super helpful!

 

[Jules123]

Nothing wrong with that consumer unit. (ish)

It has two RCDs!

He can't even count.

You could get the 40A MCB changed to a 20A or 25A, they are available if you want.


Now, it is the case that that consumer unit does not meet current standards, but in itself that doesn't mean it has to be changed.

If there is any sign of heat damage and/or a couple of other things, then it should be changed.

But from your photos, there is no evidence that a change is mandatory.

Thanks so much for your time Julie! Super helpful

 

[Vortigern]

Frankly I beleive that he has breached trading standards in that he has suggested you must have something that actually you do not need. This is fraudulent and he could be prosecuted for such fraud.