Electric shower question

[londoner1]

Hiya,

Need some advice on showers.

My CU will need to be upgraded and i have a 9.5kw shower in the house, i plan to install another one as will.

Will i be able to add the second showers to an uprated CU unit?

thanks.

 

[LearningSpark]

Will you be using both at the same time?

 

[ericmark]

Round figures 9.5kW = 40A so two = 80A now incoming DNO fuse will be in a 100A holder but anywhere between 60 and 100 amp. This is more of an issue than the CU. Also why second shower. My mothers house has three showers, one is hot water supplied, one in bath, and one in bedroom there is no way all three will be used together as only one person lives in the house so there is no problem as far as overloading the DNO fuse.

But with 5 in the house then it would be very different. As far as the CU goes you can have 12 showers as long as no more than 3 used together. I would consider using hot water rather than direct electric, one because they are better anyway, and two because the load is less even if the water is electric heated.

 

[londoner1]

Will you be using both at the same time?

No.

 

[LearningSpark]

Shouldn't be a problem then.

 

[ban-all-sheds]

Will you be using both at the same time?

No.

How will you ensure that?

 

[ericmark]

Will you be using both at the same time?

No.

How will you ensure that?

That was also my thought. I have been surprised how many houses only have 60A fuses. I would think the chance of a 60A fuse blowing with 80A with two showers running is rather low. But bet if it does it will be at the most inopportune time. Like every one getting ready to go to a wedding.

 

[EFLImpudence]

But bet if it does it will be at the most inopportune time. Like every one getting ready to go to a wedding.

Not all bad, then.

 

[ban-all-sheds]

Eric's observation implies that there might be an opportune time for the service fuse to blow leaving at (least ) two wet and soapy people in the showers and no electricity for hours.

 

[flameport]

Will i be able to add the second showers to an uprated CU unit?.

Some consumer units might be suitable for such loads, but this is only one of several things to consider.

What cooking appliances are in the building - hob electric/gas, oven single/double, gas/electric, freestanding cooker etc?
How is the building heated?
What is the mains water pressure and flow?

 

[Steve]

Electric showers are poo. Especially in winter. I have a thermostatic mixer shower running off a 28kw combi boiler. Far better than a piddly 9.5kw shower and no dodgy contacts to burn out. You must get a thermostatic model with a combi boiler or the temperature will be all over.

 

[londoner1]

Will i be able to add the second showers to an uprated CU unit?.

Some consumer units might be suitable for such loads, but this is only one of several things to consider.

What cooking appliances are in the building - hob electric/gas, oven single/double, gas/electric, freestanding cooker etc?
How is the building heated?
What is the mains water pressure andElectrib flow?

Ceramic hob at 32a /electric oven at 32a never had isssues as don't use at same time and on same mcb.
Building is gas throgh combi
Water mains pressure is fine..
Curently use a 9.5kw shower on 10mm2 cable short run cable and only on a 32a mcb (works fine)

Only have a 60A fuse box which will be replaced.

 

[flameport]

Ceramic hob at 32a /electric oven at 32a never had isssues as don't use at same time and on same mcb.

2 electric showers cannot be fitted.

Building is gas throgh combi.

Use that for one of the showers.

CWater mains pressure is fine...

Meaningless, pressure and flow need to be measured when in use and at different times of the day.

Curently use a 9.5kw shower on 10mm2 cable short run cable and only on a 32a mcb (works fine)

A 32A MCB is not suitable for a 9.5kW shower, and if it's the same MCB being used for the cooking appliances it was installed by someone who either had no idea what the were doing, did not care, or both.

 

[ban-all-sheds]

Ceramic hob at 32a /electric oven at 32a never had isssues as don't use at same time and on same mcb.

But they don't draw as much as a shower. The oven, particularly, will be nowhere near as much - it is much less than a 32A load. The hob will also be less. The two together are probably a load of about 20A.

Building is gas throgh combi

As flameport says - use that for a shower.

Curently use a 9.5kw shower on a 32a mcb

And a 9.5kW shower draws how many amps?

Only have a 60A fuse box which will be replaced.

1) That won't change the rating of the service fuse.

2) Do not get the idiot who installed the shower to change the CU.

 

[londoner1]

Ceramic hob at 32a /electric oven at 32a never had isssues as don't use at same time and on same mcb.

2 electric showers cannot be fitted.

Building is gas throgh combi.

Use that for one of the showers.

CWater mains pressure is fine...

Meaningless, pressure and flow need to be measured when in use and at different times of the day.

Curently use a 9.5kw shower on 10mm2 cable short run cable and only on a 32a mcb (works fine)

A 32A MCB is not suitable for a 9.5kW shower, and if it's the same MCB being used for the cooking appliances it was installed by someone who either had no idea what the were doing, did not care, or both.

Yes i know.

CU due to be changed soon as well as the 60A main fuse.

Current shower working fine for 5 years, 9.5kw (previous used to be a 10.5kw which was replaced as broke down but used to trip after 10 mins of continued use understandable as needs 40a mcb) on 32a mcb (which is wrong on paper).
Cooker hob and oven on separate 32a mcb 6mm2 cable feed.

Above was done years ago before i bought the house.


My choices are:

Get a higher rated CU that allows 2 showers to be fitted but not used at the same time (not ideal and wont get past BC).
Get a thermostatic shower fitted. (But gas cost is higher than electric).