10.5kw Electric Shower -Fuse Question.

ITtim

Hmmm, ok, i assumed it was related to the thickness of the wire. Now I am a little worried. So roughly how wide would the cable be? The wire was pretty thick at the end that I wired into the shower unit.

I'm going to give a sparky I know a call, i'm finding it hard to get a 45amp wylex trip anyway and think I may benefit from a new consumer unit.

It would be too hot to run the shower at anywhere near full temprature so with that in mind and currently only having the 40amp fuse am I ok to use the shower while I sort it all out? It also has an isolating power cord before the shower.

also, how do i know what cable is installed, i've just had a look on the parts of the cable that are visible in our airing cupboard and cannot see any thing printed on it.

mikey72

14mm sheath is 6mm cable, which would run the 8.5kw shower, a 32A breaker would normally be fitted if you're replacing fusewire.
It was an 8.5kw shower for a reason, you can't run a 10.5kw shower on the existing cable.

ITtim

Thanks Mikey,

Looks like its going to cost me a few bob!

keystone

ITtim wrote: »

..................am I ok to use the shower while I sort it all out? It also has an isolating power cord before the shower.

No, No and thrice NO. You took an enormous risk yesterday and would only be compounding it with the info you've provided today.

also, how do i know what cable is installed, i've just had a look on the parts of the cable that are visible in our airing cupboard and cannot see any thing printed on it.

You need to check the CSA of the conductors. But its not only that which matters. Its also the length of the run and the routing which needs to be considered.

I can't stress this enough - DO NOT USE THIS SHOWER AGAIN UNTIL IT HAS BEEN PROPERLY CHECKED BY A QUALIFIED ELECTRICIAN.

Cheers

baldelectrician

mikey72 wrote: »

14mm sheath is 6mm cable, which would run the 8.5kw shower, a 32A breaker would normally be fitted if you're replacing fusewire.
It was an 8.5kw shower for a reason, you can't run a 10.5kw shower on the existing cable.

If you are going to give advice then make sure it's accurate

A 8.5 Kw shower is 35A-37A (depending on 240v or 230v), so a 32A MCB is inadequate

Nobody has mentioned an RCD.
A RCD is a requirement for shower installations in the UK now.

The 45A mcb won't fit as it is not suitable for the consumer unit (or the way) you are installing it in.

There is a strong possibility you have an old Wylex consumer unit with a 60A main switch - putting a 45A load on a 60A main switch that has to supply the rest of the house may be pushing thinge too much

You may even need 16mm cable if the run is long or the cable is surrounded by insulation.

You should use a competent person for the work, links below
In Scotland:
Individuals registered;
http://www.sbsa.gov.uk/register/ListAC.asp
Companies
http://www.sbsa.gov.uk/register/SearchRegCo.asp?T=Construction
In England and Wales:
http://www.competentperson.co.uk

Owain_Moneysaver

ITtim wrote: »

I'm going to give a sparky I know a call, i'm finding it hard to get a 45amp wylex trip anyway and think I may benefit from a new consumer unit.

I don't think you can get 45A trips or fuses for old Wylex boards, and yes you probably would benefit from a new CU and possibly rewiring the shower circuit.

Owain_Moneysaver

The defendant pleaded guilty to charges that included using a method of wiring not in accordance with the British Standard, and failing to advise the complainant that the incomplete shower should not be used and that it was awaiting checking. He was fined £1,000 for the Part P offence and £250 each for the remaining offences ... The court also ordered the defendant to pay £1,066 in costs. Source.

A coroner has criticised Bristol City Council after an inquest heard how a tenant was electrocuted by a faulty shower. Source.

mikey72

baldelectrician wrote: »

If you are going to give advice then make sure it's accurate

A 8.5 Kw shower is 35A-37A (depending on 240v or 230v), so a 32A MCB is inadequate

Nobody has mentioned an RCD.
A RCD is a requirement for shower installations in the UK now.

The 45A mcb won't fit as it is not suitable for the consumer unit (or the way) you are installing it in.

There is a strong possibility you have an old Wylex consumer unit with a 60A main switch - putting a 45A load on a 60A main switch that has to supply the rest of the house may be pushing thinge too much

You may even need 16mm cable if the run is long or the cable is surrounded by insulation.

You should use a competent person for the work, links below
In Scotland:
Individuals registered;
http://www.sbsa.gov.uk/register/ListAC.asp
Companies
http://www.sbsa.gov.uk/register/SearchRegCo.asp?T=Construction
In England and Wales:
http://www.competentperson.co.uk

You're confusing load and rating.
The cable is rated at a maximum of 32A in this application, without seeing the run. Also that's the rating of the biggest Wylex breaker that will still be safe.
The load is determined by the shower, which was 8.5kw, and was fitted previously with a 40A breaker, and now trying to install a 45A.
Just fitting a larger breaker is unsafe, even the 40A is dubious without seeing it, and I wouldn't suggest putting it back in.
The op is getting a sparky, hopefully it'll be sorted correctly.