showers

[ibcinnes]

Recently my 26yearold shower packed up. I don't use it much as I prefer a good soak in the bath.
The old shower was a Triton 7.0kW (30A), and the one I would like to install is another Triton, but 7.5kW (32A).
However when I check the fuse rating on the Consumer Unit the shower fuse is 30A, and the total limit for this CU is 80A, which is just the total at present.
What would be the implications if I simply installed the shower as it is now and left the fuse on a 30A?

For info, as far as I can ascertain, the wiring for the shower is 10mm.

 

[riveralt]

Recently my 26yearold shower packed up. I don't use it much as I prefer a good soak in the bath.
The old shower was a Triton 7.0kW (30A), and the one I would like to install is another Triton, but 7.5kW (32A).
However when I check the fuse rating on the Consumer Unit the shower fuse is 30A, and the total limit for this CU is 80A, which is just the total at present.
What would be the implications if I simply installed the shower as it is now and left the fuse on a 30A?

Your problem will be that the new shower will require the additional protection of an RCD to comply with the manufacturers instructions - additionally they require a 35A fuse.
For Triton only their 7kw showers operate under a 30A fuse - and I don't know if they make them anymore.

For info, as far as I can ascertain, the wiring for the shower is 10mm.

I suspect that will not be the case - probably 6mm ² possibly 4mm ² T&E.

I think you may have to bite the bullet and get someone in to add a shower Consumer Unit to your installation and run new cable - possibly 10mm ² T&E from it to the new shower - if you do go down that route I would suggest you get a 9.5kw shower.

 

[EFLImpudence]

You do seem to be rather a doom merchant lately.

Why on earth will the OP need a 10mm² cable installed?

If he is quite happy with a 7.5kW one for the rare occasions he doesn't have time for a soak then he can have one.

Also, what is this 31.25A appliance going to do to a 30A fuse?

 

[riveralt]

You do seem to be rather a doom merchant lately.
Why on earth will the OP need a 10mm² cable installed?

If he is quite happy with a 7.5kW one for the rare occasions he doesn't have time for a soak then he can have one.

Also, what is this 31.25A appliance going to do to a 30A fuse?

So what you are saying is that the OP can go ahead and fit this replacement shower - yes?

 

[EFLImpudence]

Yes.

Here is my first reply which you beat me to it.

Recently my 26yearold shower packed up.

Probably cheap foreign rubbish.

The old shower was a Triton 7.0kW (30A), and the one I would like to install is another Triton, but 7.5kW (32A).

Actually 31.25A

the total limit for this CU is 80A, which is just the total at present.

It's probably not. You don't just add up the fuses.

What would be the implications if I simply installed the shower as it is now and left the fuse on a 30A?

None. It'll be fine but don't go any higher than 7.5kW.

For info, as far as I can ascertain, the wiring for the shower is 10mm.

That's not likely - probably 6mm²


It would be required and wise to have an RCD fitted to the circuit for safety.

 

[riveralt]

Yes.

So that is a yes but..

It would be required and wise to have an RCD fitted to the circuit for safety.

So, are you suggesting now that the OP replaces the shower and puts an in line RCD in the circuit - or are you suggesting that he get someone in to help him and properly assess this circuits characteristics.

 

[EFLImpudence]

It would be required and wise to have an RCD fitted to the circuit for safety.

So, are you suggesting now that the OP replaces the shower and puts an in line RCD in the circuit - or are you suggesting that he get someone in to help him and properly assess this circuits characteristics.

As will be apparent from my correct English, I was suggesting that -
"It would be required and wise to have an RCD fitted to the circuit for safety."

This is a separate matter from whether the shower can be replaced with one of 7.5kW.

 

[ibcinnes]

Just to assure everyone, I checked the size of cable at local DIY shop, and it is definitely 10mm².
So can I go ahead and fit the 7.5kW shower?

 

[Spark123]

What does the instruction book say about RCD protection? Do you have any RCD protection?
To be pedantic you are not meant to have anything over 30A on a 30A fuse. Is it a Wylex consumer unit?

 

[riveralt]

Just to assure everyone, I checked the size of cable at local DIY shop, and it is definitely 10mm².

Okay -
10mm ² T&E would normally have a stranded earth wire - does it?

So can I go ahead and fit the 7.5kW shower?

Depends on whether you follow the manufacturers instructions or EFL - but whatever the case you will need to fit an RCD.

 

[ibcinnes]

The CU is a Memera 3, fitted 26 years ago when hose was rewired.

Presumably someone is going to tell me that this requires replacing as well.

However please bear in mind that I need to keep the expense to a minimum, and I don't want to be spending many 100's ££ to install a shower I only use perhaps twice per week.

 

[ibcinnes]

That should read 'when house was rewired'

 

[Spark123]

If it needs £100s to be done safely then so be it, you'll just have to go smelly
What does the shower instruction book say about RCD protection and do you have any?

 

[riveralt]

At the end of the day its your house and installation you can do whatever you like to it.

I will always state to DIYers that you should follow the manufacturers instructions - so for a Triton 7.5kw shower the manufacturers instructions state that you should have a 35A fuse and RCD protection.
Since I don't think Memera 3 fuses go beyond 30A then if you follow my advice you will need to have someone fit a Shower Consumer unit with an appropriately sized MCB and a RCD.
If you take others advice I will have to leave it to them to advise you on the best way forward.

 

[ban-all-sheds]

That should read 'when house was rewired'