Two electric showers 45A in single property

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Hi,


We are considering installing two 45A shower in a single property (multible showers). I believe the incoming service fuse is 100A.


The problem is, if both showers plus other devices are used it could exceed the 100A max.


Would it not matter as it's unlikely both showers used at the same time? I've seen one solution is installing a 'priority' board to prevent both being used at the same time, or a switch arrangement that performs the same function.


Both showers would be on there own circuits with RCBOs.

- -

Is there any scope for additional mains supply, or would this be too expensive, potentially cause phasing issues, or non reg?

Finally, if both showers were used at the same time could water pressure in an issue?

Thanks in advance.
 
If the fuse really is 100A, I wouldn't worry
Yeah, what could possibly go wrong!

Are you sure your supply is 100A?
The service fuse cover may have 100A written on it, but that is the maximum fuse. Inside it may be 80 or 60A. Ask your DNO.
100A is the max for a single phase domestic supply. To go larger, you would need to ask for perhaps a 3-phase supply, but that’s several thousands of pounds to install.

Better, perhaps, to have one electric shower, and use the existing hot water supply, perhaps with a pump, to provide the second one.

These sort of showers need mains water pressure and, of course, the pressure will halve if both showers are in use.
 
100A supply fuse question IMG-20210126-01501.jpg
100A supply fuse question IMG-20210126-01501.jpg

This is the power inlet. Does the 100A here refer to the fuse or max current for the unit?
 
Thanks for the advice. Unfortunately, we are on electric heating, so may need to rethink. There is no gas supply currently to house. So maybe electric hotwater storage system and power showers?
 
I've seen one solution is installing a 'priority' board to prevent both being used at the same time, or a switch arrangement that performs the same function.
... indeed, and that would seem to be perhaps the most obvious course for you, since it removes many of the questions and uncertainties.

Kind Regards, John
 
You can get relays that prevent both showers from being turned in at the same time.
 
In a single dwelling, you can also decide, arrange and ensure not to use both at once; just like if you only had one shower.
 
Thanks for the advice. Unfortunately, we are on electric heating, so may need to rethink. There is no gas supply currently to house. So maybe electric hotwater storage system and power showers?
You haven't said where your hot water comes from at the moment, but you could install a largish unvented hot water cylinder and heat the water with an immersion heater, or two.
You'll then get hot water showers at mains water pressure.
 
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