Shower 8.5 on a 40mcb is it dangerous

chrismoy1 · Mar 2, 2019

Hi guys

My tenant just had an electrician in to connect her cooker and has told her that the shower is dangerous and not to use it because it has a 40 mcb in the consumer unit and it should be a 32.
The cable is 6mm and the shower is 8.5kw.

Can you advise me please
Thank you in anticipation

Toneyz · Mar 2, 2019

Is the shower protected by an RCD and is the cable under insulation would have a factor on the answer.

davesparks · Mar 2, 2019

Ask for this to be put in writing by the electrician, explain that you need them to specify the exact regulation numbers which they are referring to and ask them to explain exactly how it is dangerous.

It 8s possible that the installation may not comply with the current regulations, but it may not necessarily be dangerous.

littlespark · Mar 2, 2019

The electrician was there to connect the cooker. He didn't have to mention anything about the shower circuit.

Mike177 · Mar 2, 2019

Sure that 6mm can only take more than 40A if clipped direct.
So a 32A would be a sensible option surely? 8.5kw is about 35/36 amps.
So smaller shower or bigger cable.
Or is my memory and maths failing me as much as my Fantasy football team?

buzzlightyear · Mar 2, 2019

chrismoy1 said:
the consumer unit and it should be a 32.
The cable is 6mm and the shower is 8.5kw.

ask you tenant to ask the say sparky to work out the loading ,any way what is the shower to do with the cooker ,or is any water coming out of the cooker .

chrismoy1 · Mar 2, 2019

anthonybragg said:
Is the shower protected by an RCD and is the cable under insulation would have a factor on the answer.

Hi Anthony
The cable is clipped direct and is not surrounded by or under any insulation.

Regards Chris

chrismoy1 · Mar 2, 2019

anthonybragg said:
Is the shower protected by an RCD and is the cable under insulation would have a factor on the answer.

RCD in the consumer unit.
Regards Chris

chrismoy1 · Mar 2, 2019

Mike177 said:
Sure that 6mm can only take more than 40A if clipped direct.
So a 32A would be a sensible option surely? 8.5kw is about 35/36 amps.
So smaller shower or bigger cable.
Or is my memory and maths failing me as much as my Fantasy football team?

Hi Mike
I thought an 8.5 would draw a current of 35.5A so you would need an mcb higher than that and the next one up is 40.
Regards Chris

Dave OCD · Mar 2, 2019

Chris, this is the correct sized MCB for a 8.5kW shower, a 32amp device would be running at a slight overcurrent and although it would take a long time to trip it's not permitted in the regulations. I can't stand people who find fault with work unrelated to what they're doing - especially when they're spouting BS.

chrismoy1 · Mar 2, 2019

Dave OCD said:
Chris, this is the correct sized MCB for a 8.5kW shower, a 32amp device would be running at a slight overcurrent and although it would take a long time to trip it's not permitted in the regulations. I can't stand people who find fault with work unrelated to what they're doing - especially when they're spouting BS.

Thank you very much Dave for a very clear decision on this question.

Regards Chris

Deleted account · Mar 2, 2019

littlespark said:
The electrician was there to connect the cooker. He didn't have to mention anything about the shower circuit.

Dont think I agree there, if I saw a potentially dangerous situation I would point it out.

Saying that this is not a good example of that, as it's not a potentially dangerous situation.

chrismoy1 · Mar 2, 2019

Paignton pete said:
Dont think I agree there, if I saw a potentially dangerous situation I would point it out.

Saying that this is not a good example of that, as it's not a potentially dangerous situation.

So you are sure it is not dangerous because I think my tenant will still want it changed to a 32 because an electrician has told it is dangerous and must not use the shower.

Regards Chris