INSTALLATION OF ELECTRIC SHOWER 10.5KW - New Member Too!

[ricky_lion]

Hi Folks, Im new on here and it's great reading the posts.

I want to install a 10.5KW electric shower. A Triton Topaz 100si. I have a Proteus consumer unit about 15 years old and the fuses are not available for it above 40A. To get round this I was advised by Proteus to buy a separate Shower Consumer Unit - I have brought an MK IP65 from Screwfix Direct for £29.99 which incorporates a 50A MCB and a 63A RCD switch. This then provides in line RCD protection as recommended in the shower installation instructions.

My questions are: how will this new separate shower consumer unit be connected in??? My old consumer unit has a 100A main switch. Can I simply wire the shower consumer unit using say 10 or 16mm cable (maybe thicker?) to the 100A main switch and mount it next to or above the main consumer unit or is it all more complex than this? I'd prefer to not have to buy a whole new consumer unit if I can help it.

Also what cable is best to wire the shower in? 10 or 16mm? The wires will not be buried but clipped in the loft and down a cupboard in the bathroom into the shower mounted on the outside cupboard wall.

Thanks for any help!

Ricky

 

[ban-all-sheds]

My questions are: how will this new separate shower consumer unit be connected in??? My old consumer unit has a 100A main switch. Can I simply wire the shower consumer unit using say 10 or 16mm cable (maybe thicker?) to the 100A main switch and mount it next to or above the main consumer unit or is it all more complex than this?

I'm afraid it is - the main switch in your CU will not take two sets of cables, and as the cable won't be protected by anything other than the main service fuse, 10mm² won't be big enough and 16mm² almost certainly won't be either.

The solution is to take the meter tails that currently go directly to the CU into a service connection block, or service splitter, often called a Henley block, and then have two outgoing sets of tails, one to the CU, and one to your new shower unit.

Unless you already have an isolation switch fitted, this means that you have to pull the service fuse to isolate everything, and this is not something that DIYers are advised to do, particularly one who, if you'll forgive me, seems from his questions to lack experience.

So you'll probably have to get an electrician.

I'd prefer to not have to buy a whole new consumer unit if I can help it.

That won't be necessary, although if it doesn't have an RCD it might be worth considering.

Also what cable is best to wire the shower in? 10 or 16mm? The wires will not be buried but clipped in the loft and down a cupboard in the bathroom into the shower mounted on the outside cupboard wall.

10mm² will be fine, but if you want to stay within the law then you'll have to get the electrician to do all of that, and the shower installation as well.

 

[ricky_lion]

Thanks for the help. I am going to get an electrician in to do all this. I want to know really what they will be doing.

Do you know how much a spark would charge to install the shower consumer unit to one of these henley blocks and is it a difficult or large job?

Whats the best recommendation?

1. Install an entire new consumer unit (shame as the one I have works)

2. Use the shower consumer unit and wire into this henley block???

3. Can a 45A MCB be installed in my old consumer unit even? I have an MCB in a packet and the dimentions of the protruding part with the switch on it are the same as the fuse holders in my consumer unit.

I wouldn't attempt any of this myself but I like to know what the options are and how jobs would be undertaken before I let anyone out of the Yellow Pages loose on my home!

 

[ban-all-sheds]

Do you know how much a spark would charge to install the shower consumer unit to one of these henley blocks and is it a difficult or large job?

Please see #9 here: //www.diynot.com/forums/viewtopic.php?t=19448

1. Install an entire new consumer unit (shame as the one I have works)

But has no RCD, I would guess...

2. Use the shower consumer unit and wire into this henley block???

Simplest & cheapest, not necessarily the best.

3. Can a 45A MCB be installed in my old consumer unit even? I have an MCB in a packet and the dimentions of the protruding part with the switch on it are the same as the fuse holders in my consumer unit.

It might fit, but there are other factors to consider apart from aperture size, such as busbar fitting type. Also, that would mean you would not have RCD protection on the shower...

I wouldn't attempt any of this myself but I like to know what the options are and how jobs would be undertaken before I let anyone out of the Yellow Pages loose on my home!

Personal recommendation is, as ever, the most reliable way. Other than that the usual approach of at least 3 quotes, talk over exactly what the guy recommends, make sure you are happy etc etc, and also make sure that whoever you pick is registered with one of the Competent Person schemes and can self-certify compliance with the Building Regs. Do not get flanelled into accepting just certification of compliance with the Wiring Regs - Building Regs certification is not the same and it is the law.