Has the correct shower been fitted?

[Molly17]

Hi...a bathroom company has fitted an electric shower 9.8kw, we have just found out our cable is 6mm. They had a plumber and a chap who was not a qualified electrician do the first fix of fitting the shower and also putting in down lights in the ceiling and they got an electrician to 2nd fix. We haven’t yet had any certificates from them for the electricians work. Should I say anything to them or is everything fine with this?? Advice would be appreciated. Thank you

 

[davesparks]

What size MCB is the 6mm cable protected by?
How long is the cable and how is it installed, does it pass through insulation at any point in its run?

 

[Molly17]

What size MCB is the 6mm cable protected by?
How long is the cable and how is it installed, does it pass through insulation at any point in its run?

Oh I’ve no idea, can you see what you need from the pictures? The box is in our garage and the bathroom is upstairs, the cable as far as I know goes into attic and then into bathroom inside the plastered wall

 

[davesparks]

That picture is unclear, can you post a picture that shows the writing on the circuit breakers clearly?

 

[Molly17]

That picture is unclear, can you post a picture that shows the writing on the circuit breakers clearly?

I’ll get one in the morning, thank you for trying to help me
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Is this what you need or something else?

 

[radiohead]

The new shower will draw a current of over 40a, and it is on a 32a device. Not compliant. Whether the 6mm supply cable is adequate depends on the length and way it is installed, but I would think it is most likely that a 10mm cable would be required. However it is unlikely that in it's present form it is dangerous, or will give any trouble. The circuit is only loaded for relatively short periods....(unless my daughter is using it). A lower rated shower and replacing the 32a for a 40a device (if installation method allows) would have been the way to go.
If the shower is a straight replacement no certification is required, if wiring has been installed or altered then it is, same for the downlights.

 

[Midwest]

Do you have two electric showers? And I see you have a 40A cooker supply.

 

[Molly17]

Do you have two electric showers? And I see you have a 40A cooker supply.

Hi yes we have an old shower in the en-suite which is I think 8.7 kw. My oven is electric neff double oven with a gas hob
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The new shower will draw a current of over 40a, and it is on a 32a device. Not compliant. Whether the 6mm supply cable is adequate depends on the length and way it is installed, but I would think it is most likely that a 10mm cable would be required. However it is unlikely that in it's present form it is dangerous, or will give any trouble. The circuit is only loaded for relatively short periods....(unless my daughter is using it). A lower rated shower and replacing the 32a for a 40a device (if installation method allows) would have been the way to go.
If the shower is a straight replacement no certification is required, if wiring has been installed or altered then it is, same for the downlights.

There was a shower there before, but an old one with less power. The down lights are new. I wasn’t sure if an electrician should have done all the work and not just come at the end to check it was ok? The only reason I am questioning this is our other shower needs replacing and when we went to look for one they asked us about the size of our cable and said we couldn’t have a high kw shower, which then got us worrying about the one we have recently had fitted and if they have done the lights ok, because they didn’t mention the cable size to us
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Hi yes we have an old shower in the en-suite which is I think 8.7 kw. My oven is electric neff double oven with a gas hob
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There was a shower there before, but an old one with less power. The down lights are new. I wasn’t sure if an electrician should have done all the work and not just come at the end to check it was ok? The only reason I am questioning this is our other shower needs replacing and when we went to look for one they asked us about the size of our cable and said we couldn’t have a high kw shower, which then got us worrying about the one we have recently had fitted and if they have done the lights ok, because they didn’t mention the cable size to us

 

[robd]

Basically they've fitted a shower that's too big for the breaker and if the breaker isn't tripping it's more by luck than judgement I would say. I wouldn't have thought any thing would come to any harm from it but it's not what I would have done myself

 

[R-fur]

Got a similar one last week, customer had fitted a new shower and complained that it tripped if he and his wife had a shower right after the other, or when the daughter was using it. 8kW shower 35A on a 6mm circuit with a 32A RCBO. Majority of the circuit is clipped in the cellar so I am going to fit a 40A RCBO. Not ideal but compliant.

 

[123]

Got a similar one last week, customer had fitted a new shower and complained that it tripped if he and his wife had a shower right after the other, or when the daughter was using it. 8kW shower 35A on a 6mm circuit with a 32A RCBO. Majority of the circuit is clipped in the cellar so I am going to fit a 40A RCBO. Not ideal but compliant.

I wouldn't expect 35A to trip a 32A MCB or RCBO, are you sure that's all the load is and it's not something higher?

 

[freddo]

Lol had exactly the same last week, 8.5KW shower tripping 32A MCB, had been 'ok' for several years. Clamp meter read 35A. I can't see a 32A MCB holding for too long at 9.5KW.

 

[radiohead]

Lol had exactly the same last week, 8.5KW shower tripping 32A MCB, had been 'ok' for several years. Clamp meter read 35A. I can't see a 32A MCB holding for too long at 9.5KW.

Probably will hold for the duration of a shower, or even longer. But it'll stress the mcb over time and eventually it'll start tripping rather more promptly.

 

[freddo]

Probably will hold for the duration of a shower, or even longer. But it'll stress the mcb over time and eventually it'll start tripping rather more promptly.

Yes this must be the case, the 'available showering time' was getting shorter and shorter. Unless the transformer taps were recently changed and the supply voltage went up!

 

[Pretty Mouth]

Lol had exactly the same last week, 8.5KW shower tripping 32A MCB, had been 'ok' for several years. Clamp meter read 35A. I can't see a 32A MCB holding for too long at 9.5KW.

I came across one a few months back while installing a cooker. It had been installed by the home owner, he claimed it was 10.8kW, and swore they'd never had any problems with the MCB tripping. 32A breaker/6mm² cable.

Pulling a current of 1.46 times the rated current of the breaker, it could take up to 1 hour to trip (or so I am led to believe)

 

[R-fur]

Just to see what would happen I put 40A through a 32A type 2 MCB it took 8 and a half minutes to trip. Just enough time for a quick shower.
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@123 I tonged the circuit, 35A at 240V I make that 8.4 kW

 

[Markyd]

I thought the new shower was 9.8kw...not 8.4.......42.5a on a 32a breaker and 6mm cable surely that is not right and needs looking at

 

[Molly17]

I thought the new shower was 9.8kw...not 8.4.......42.5a on a 32a breaker and 6mm cable surely that is not right and needs looking at

Hi my shower is 9.8 Kw with 6mm cable and 32a fuse

 

[R-fur]

@ Markd
I was referring to my case that I mentioned in post 10.