Elec shower upgrade

[pwoody83]

Hello all , this is my first post to the site. Appreciate all replies.

Before I ask I am not going to be carrying out this work, I will be getting a qualified spark in to do it. I am asking for opinions and so I know what I am quoting for.

Currently have a 7.5kw shower and am looking to up it to 9.5kw shower.
I have 10mm2 t&e cable running approx 11m from a separate cu for shower. This is the set-up inside my cupboard. Single cu is 45a rated. Unsure of the rcd fuse that sits in it.

How dated is this set-up?
And should there be a rating on the rcd?
View media item 82921 View media item 82922 View media item 82923

 

[sparkwright]

I would guess there is no RCD protection for that shower circuit.

Also, what makes you think the circuit cable is 10 mm²?

 

[bernardgreen]

That is not an "RCD fuse" as there is no such thing as an RCD fuse. It is a switch fuse

The supply to the switch fuse comes from the consumer unit and may be protected by the RCD in the consumer unit or it may not. If it is not protected then get an electrician to replace the switch fuse with a shower CU which will have an RCD ( earth leakage ) and MCB ( over current ) protection

One step further.... It looks like there may be one RCD covering all circuits in the CU. That is not optimum as a fault / accident on a power socket or appliance would also take out the lights. Not good if the accident that took out the RCD involved injuries requiring treatment. If you only have a cordless phone then without power to the base station it would be impossible to call 999

 

[pwoody83]

Thanks for the replies.

A quick check with cable crimp and also used this guide to determine cable: http://www.diynot.com/wiki/electrics:cable_types:flatpvccables

That makes sense about the rcd's I will get those installed.

 

[pwoody83]

And also the cable re-checked during the work!

 

[RF Lighting]

I can absoloutley assure you that you do not have 10.0mm² cable to your shower. That is 6.0mm² that you have.

Might be time to rethink your plans.

 

[Taylortwocities]

I can absoloutley assure you that you do not have 10.0mm² cable to your shower. That is 6.0mm² that you have.

Might be time to rethink your plans.

What he said^^^^^^

Also, I would be very interested to see how the tails from the switch fuse are connected inside the consumer unit.

 

[ericmark]

As said from age of set up unlikely to have 10mm² more likely 6mm² with a single RCD likely house earth is TT and the RCD is 100mA not 30mA required for personal protection.

So to upgrade shower is likely going to be expensive. Much will depend on what the electrician finds and is prepared to do. Likely it will involve a new circuit which in turn will mean Part P registered work so the electrician has to follow scheme provider rules.

This may mean a new consumer unit so the job could very easy cost £500. So step one is get some quotes then decide what next move is.

I know what I would do and I am sure most the electricians on the forum have an idea what they would do but that does not matter all that matters is what the electrician you select is willing to do.

 

[securespark]

The grey tails feeding the 104 must be piggy backed off the RCD incomer.

 

[ban-all-sheds]

Will that be a connection which the RCD was designed to safely accommodate?

 

[pwoody83]

Appreciate all your insights, this is turning into a much larger job than first anticipated and with plenty of other small to medium projects that need doing, the electric cupboard overhaul will have to wait untill the new year.

Which has steered me down the combi boiler-fed shower install.

 

[ban-all-sheds]

You'll get a much better shower that way anyway - an instant heater with, what - 4x? - the power of the electric one.

 

[bernardgreen]

Which has steered me down the combi boiler-fed shower install.

When choosing the combi remember that the temperature of hot water feeding the shower may drop when a hot tap is turned on somewhere else in the house and thus the shower become cooler even cold. Then when that tap is turned off the temperature of the shower will rise back to what it was. Adjusting the temperature when the shower goes cold means the shower can be very hot ( dangerously hot ) when the other tap is turned off.

A thermostatic controlled shower will reduce the effect but the response time of the thermostat will still allow a burst of cooler water and then a burst of hot water ( when the tap is turned off ).

While the cold burst is harmless the hot burst in extreme circumstances could cause a scald.

 

[Steve]

You will ALWAYS get a better shower from a thermostatic mixer fed from a combi. Your combi has between 24-48kw of power! Rather than the 11kw maximum you can squeeze out of our puny electricity supplies on one appliance at once.

I have a 28kw combi with a fairly cheap triton bar thermostatic mixer and the shower is brilliant. It also opens up the door for fancy rainfall shower heads etc, impossible with electric showers, though there is always a limit with instant heated water even from a combi boiler.

Being thermostatic means if someone flushes the bog the shower slows but tries to maintain the temperature.

For the very best shower you need a pumped stored hot water source. Used to have this but had the cylinder removed, replaced with a combi as above.

Will never go back to electric shower.

 

[bernardgreen]

Being thermostatic means if someone flushes the bog the shower slows but tries to maintain the temperature.

tries being the operative word.

For the very best shower you need

mains pressure with the hot side heated by passing through a coil in the top of a cylinder of stored hot water .[/quote]