Consumer Unit for 10.5kw & 8.5kw showers?

[zedman]

Can I use a Volex Shower Consumer Unit, Screwfix Item: 69659 to connect both a 10.5kw (main bathroom)& an 8.5kw shower (en-suite) using 2 seperate 10.0mm TE cables.
It has a 63A 30mA RCD & comes with 1 x 50A Type B MCB & has space for another MCB.
Obviously I would need another MCB for the 8.5kw shower,
Q. 40A or 50A.
Any advice would be appreciated. Thanks

 

[plugwash]

not really

personally i would advise against two electric showers on a domestic sized supply but if you must do it then i would advise using two totally seperate shower CUs both wired directly to a DP henly in the tails along with the existing CU

also bear in mind that to fit then henly someone is going to have to pull the main fuse (unless there is already a seperate isolator in place) while not too dangerous provided the load is off and you take reasonable care not to touch any metal when pulling the fuse it is not something most people here would reccomend to diyers

 

[zedman]

Thanks for the advice Plugwash, I've had conflicting advice from "it would be unwise" to a "definate no" & I spoke to an electrician today who basically said as you. He said that it is close to the max but allowing for diversity it was possible using 2 seperate Shower CU's as above.

 

[ban-all-sheds]

AFAIK you can't apply diversity to water heating devices, neither for their individual circuits (as when they are on, they are on 100%) nor across the whole installation.

83A of showers doesn't leave much for the rest of the house....

 

[plugwash]

and i think i mentioned it over on screwfix but if you do this it would be a good idea to put the lights in the shower rooms on dedicated cuircuits to the shower CUs supplying those rooms

the reason for this is it means you can just scrap the henly for the lives (leaving the one for the neutrals) and connect the 3 CUs to the 3 lives on a new 3 phase meter if you have problems with the 100A fuse blowing

if you did this and you had the lighting in those bathrooms on the main CU you would be left with 415V in the bathrooms which is undesirable to say the least