Electric Shower Instalation Help

[miketheleg]

Hi guys,

I have had a contractor friend of mine do work on my bathroom and it would appear he knew alot less than he lead on.

I had an electric shower in the flat and i beleive it was probably the weakest model. 6kw

I have upgraded it to 10.5kw and he has used the same size cable that you use for a cooker. These are his words... it appears that the cable is around 4mm.

This obviously isn't enough.

Is there any solution so that i can keep the more powerful shower or should i go back to the old one. Im concerned now that even that was undersupplied.

Is the only way to keep this power shower to completely wire in from the fuseboard a 10mm cable up to the shower?

Your help appreciated.

Also for the record the shower lasted two weeks before it decided not to heat water any more which is why ive investigated etc

Cheers
Mike

 

[ban-all-sheds]

I have had a contractor friend of mine do work on my bathroom and it would appear he knew alot less than he lead on.

If he installed new fixed cabling did either he or you know that it was notifiable?

it appears that the cable is around 4mm.

"Around"? It either is or it isn't - how/where are you measuring it?

This obviously isn't enough.

The best you can hope for with 4mm² is 37A...

Is the only way to keep this power shower to completely wire in from the fuseboard a 10mm cable up to the shower?

Yup.

 

[Chri5]

BaS- It was an existing cable and a unit swap.

You will have to replace the cable, it's very likely to be 10mm required, but distance of run, method of run could mean larger still.

There's also new regs to consider, as in the new 17th (from July 08) will require the house to have RCD protection and that the gas / water is earth bonded 10mm cables.

Likely to be a days work, on the bright side once done that's it for 15++ years, unless showers in 2015 become 20kw

 

[ban-all-sheds]

BaS- It was an existing cable and a unit swap.

I thought it probably was, but there was a bit of doubt in my mind because of this:

he has used the same size cable that you use for a cooker

 

[miketheleg]

ok so it is a 4mm cable... can i install this power shower and get all the electrical certificates

galaxy 1000 7.5kw power shower

nominal at 240v - 31.25 amps

min rating of isolation switch - 40amps
fuse rating - 40amps

it then gives me max cabe runs if its a 6mm or a 10mm which are 27m and 44m

I need to get an electrical certificate at the completion of the job.

also can anyone confirm if we had left the existing shower in and just moved it to another location (we shifted ends of the tub) could we have used the existing wiring and existing shower and still got a certificate... or would we not get it due to the new regulations

bascially if because we were stupid enough to take out the old one and move it do we have any other option but to run a 10mm cable from the fuse on the basis that i need to get the correct certificates in order to complete the job

thanks for your help so far guys

 

[securespark]

If you want to run 7.5kW on 4mm², then you should NOT be using a 40A breaker. Make it a maximum of 35A.

Also, what is the length of run of cable & does the route involve loft insulation or trunking?

Have you got RCD protection for this circuit?

Are there PEB's in place?

 

[ban-all-sheds]

ok so it is a 4mm cable... can i install this power shower and get all the electrical certificates

If you install the shower you won't get any electrical certificates...

min rating of isolation switch - 40amps
fuse rating - 40amps

Not on 4mm² cable - didn't you read what I wrote earlier?

it then gives me max cabe runs if its a 6mm or a 10mm which are 27m and 44m

Oh look - no details for 4mm²....

I need to get an electrical certificate at the completion of the job.

Electrical, or Building Regulations completion?

If you mean electrical then you need to get an electrician to install it.

also can anyone confirm if we had left the existing shower in and just moved it to another location (we shifted ends of the tub) could we have used the existing wiring and existing shower and still got a certificate... or would we not get it due to the new regulations

If you could have moved it without extending the circuit then you wouldn't need a certificate. As soon as you extend the circuit it becomes notifiable, and so you would need to end up with a Building Regulations completion certificate. There are only 2 routes to that:

1) You have the work done by a registered electrician

or

2) You notify LABC in advance, they test & inspect.

The cost of (2) vs (1) for a shower install will probably be higher.

bascially if because we were stupid enough to take out the old one and move it do we have any other option but to run a 10mm cable from the fuse on the basis that i need to get the correct certificates in order to complete the job

You need a new cable because of the rating of the new shower, not because you've moved anything.

You should read the articles here: http://www.diynot.com/wiki/electrics:part-p to find out more about notification etc.