Replacing shower. Electrics info please.

[merton69]

Hello all.
I placed this topic in the showers section but somebody kindly suggested that I placed the question/query here......


Our Gainsborough Energy 2000x 10.8kW has finally called it a day.

So we are in need of a new shower. Because the shower was a 10.8kW it has a thicker electric cable to supply it and Gainsborough advise that the following should be used in it's place.
The cable is 17mm wide.
http://www.gainsboroughshowers.co.uk/Customer-Services/Replace-an-old-model/#q4008

The models to select from are:-

Gainsborough Stanza 9.5 http://www.gainsboroughshowers.co.uk/shower-store/electric-shower/Stanza-95-white/

Gainsborough 1.5se http://www.gainsboroughshowers.co.uk/shower-store/electric-shower/Gainsborough-105-se/

I have attached a picture of my old shower showing cable and pipe inlets.

Gainsborough Energy 2000x

• merton69
• 25 May 2014
• 4

Can I install a new one myself (I installed the old one over 15 years ago)?
Is the cable powerful enough/ correct please?
What pitfalls should I look out for please?
Anything else?

 

[Taylortwocities]

At 17mm wide, that would indicate a cable with 10mm² conductors.
What size MCB/fuse is in the consumer unit for that circuit?

If it was supplying the 10.8KW shower I would expect the cable would be big enough for the 10.5KW model.

Your shower should (must) be protected by a 30mA RCD. Is it?

 

[merton69]

Thank you Taylortwocities.

Just had a look at the Consumer Unit and the fuse/UCB states B 50.

Hope this helps.

 

[Taylortwocities]

A 10.5KW shower pulls around 45amps. Assuming the cable is installed properly (e.g. not going through thermal insulation, etc) it is rated at 53A ish).

The 50A MCB is correct, so you are fine to go for the 10.5KW shower.
Did you check out the RCD query?


FYI, the installation manual for the Gainsborough se models, including information re electrical connections, can be found here
http://www.gainsboroughshowers.co.uk/upload/Documents/New Electric Install Guide.pdf

 

[merton69]

Thank you Taylortwocities.

As for the RCD, I am not sure what you mean by it.

The cable comes from the Consumer unit up into the bathroom and is connected to the shower on/off switch. From there straight to the shower.

 

[JohnW2]

As for the RCD, I am not sure what you mean by it. The cable comes from the Consumer unit up into the bathroom and is connected to the shower on/off switch. From there straight to the shower.

Could you provide a photo of your Consumer Unit, showing the labels etc. for the various breakers?

Kind Regards, John

 

[merton69]

Will do JohnW2, thanks.

 

[merton69]

Attached is the image requested for my consumer unit.

Hope it's sufficient.

Untitled

• merton69
• 12 Jan 2015
• 2

 

[Taylortwocities]

OK

So you do not have any earth leakage protection on the shower circuit.
This is a must have from a safety point of view.

What is needed is a 30mA double pole RCD. It can be installed at any accessible point along the shower circuit - it is usually most convenient for it to be at the consumer unit end.

The manufacturer of the shower, and the wiring regulations, require this to be fitted.

You would probably need an electrician to install this, as he/she will have the required test equipment to check that the RCD is operating correctly.

 

[merton69]

Wow! Okay and thanks for that vital info.

Just goes to show how much more strict the reg's have become.

Again thanks to all for your input on this.

 

[JohnW2]

Wow! Okay and thanks for that vital info. ... Just goes to show how much more strict the reg's have become.

It's not just bureaucracy. Many would say that a situation in which electricity, water and wet naked human bodies come into close association is just about the most extreme example of a situation in which RCD protection is desirable.

To give a balanced view, a few might try to argue that if all you are doing is replacing an existing shower, using an existing circuit, there may not be a regulatory requirement to bring the circuit up to compliance with current regulations (i.e. add an RCD). However, even if that argument could prevail (and I'm not necessarily convinced that it could), it would probably be a fairly foolish approach to take.

Kind Regards, John

 

[merton69]

Thanks JohnW2.

I agree. The reg's in this instance are for the safety of the user to which I agree.

Just a hassle that it will cost me extra for the RCD and an electrician to fit it.

Once again, thanks to all for their input. This place has definitely helped.

 

[OwainDIYer]

you might be able to get the MCB replaced with an RCBO especialy as you have a module free.

Otherwise fit something like this
http://www.screwfix.com/p/square-d-2-way-rcd-shower-consumer-unit-45a-mcb/36269
into the existing cable.

As your other circuits are not RCD protected either, you will need supplementary bonding in the bathroom.

 

[merton69]

Thank you OwainDIYer.

2 questions please:-

• What size RCBO?

• What do you mean by 'supplementary bonding in the bathroom'?

 

[Taylortwocities]

A RCBO is another solution.

You'll need one to fit that consumer unit


A Hager ADN150 1 Module 50A Single Pole Type B RCBO 6kA 30mA is what you need. But it will still need to be installed and properly tested, so you may as well get an electrician to do that for you.