one cable / one shower ?

[njkmr]

Hi Good Morning,
I am in the process of making two bedrooms and two ensuites in the loft space of my house .(planning/building consent given etc )
I have a shower downstairs in the bathroom and a shower in the ensuite bathroom upstairs,both having their own 10mm cable supply
Will I have to put two seperate 10 mm cables to the new showers .
I am thinking I will due to the amount of power they will use especially when used at same time ,but would like it confirming if possible .

Apologies if itis a totally dumb question .

 

[kkynaston]

I take it that will take your total number of elec showers to 4!

Your supply will probably not be able to cope with 2 on at the same time let alone 4! and you will probably not have enough water pressure.

If you are set on using electric showers you need a way to interlock them so that only one can be on at any one time.

With that amount of showers you may be better considering a large DHW tank and some pumps feeding mixer showers.

 

[njkmr]

they probably wont be on at same time to be honest,but are you saying my house electric supply wont be sufficient to run the showers two or three at the same time ?.I know the water pressure is good .
Would I be better off running them off my combi boiler ?
Thanks for the reply .

 

[kkynaston]

Assuming you have a 100amp service fuse
They may run but an average shower draws 40 amps.

So 2 showers would draw 80ish amps, that leaves 20 amps spare for your cooker, wmachine, dwasher, kettle (50ish amps there!)

3 Showers would definitely overload your supply, it won't blow straight away but it will damage your consumer unit by drawing too much current through the main switch which will probably only be rated at 100 amps.

Post some photos of your incomming supply and consumer unit.
I think you will definitely running the new showers off the combi tbh.

 

[njkmr]

Thanks again.I did have a new consumer unit fitted recently because the old one was about 30 years old .The new one is MK 5500 100 amp type.
I take it this wont cope with the extra,s?

 

[FingRinal]

Your MK consumer is rated for the typical single phase domestic supply - 100A. It is a maximum rating without an allowance for diversity.

Two showers is pushing it and I think many would not recommend even that without making a careful assessment of maximum demand, likely demand and the condition/design of the installation.

I'd be very surprised if you could find any registered electrician who would have anything to do with installing two electric showers in a property which already had two.

 

[njkmr]

So if the house was devided into seperate flats say for student lets ,would it then have a more substantial consumer unit to get around this .?
It isnt flats and never will be ,but there are houses with several ensuites and how have they done it .I did not think it would be much of a problem to be honest ,and I was kind of asking could two showers be run off one 10 mm cable instead of having 4 seperate ones for each of the 4 shower .
It looks like I will run two off the combi boiler .Worcester 32 i i think it is .
The chances are they will never be run all at the same time,but it was just making use of spare space and giving the two kids their own space and adding value to the property .
Regards
Rob.