Electric showers

[Sparkystu79]

Hi folks, I know the answer to this already but what’s your thoughts on running 2 x 8.5Kw showers off a sub board fed from 16mm 63amp supply?

 

[littlespark]

What’s the chances that both are being used at the same time? And is there anything else off this supply, however small?

 

[Sparkystu79]

What’s the chances that both are being used at the same time? And is there anything else off this supply, however small?

It’s a 3 phase supply with 4 showers proposed. It’ll be for school trips etc so I’d say there was a decent chance they’d be used simultaneously. I can split other loads over the other 2 phases but the 2 showers on one phase concerns me.

 

[littlespark]

Ah I see. So it’s just a single phase sub main. No chance of another phase for this?


I’ve got a similar issue with 4 showers across 3 phases at a gym… but customer also wants 2 sauna rooms and electric heating.
3 phase 200A supply into building, but limited to 80A per phase at the cutout. I’ve told the customer to get it updated.

 

[brianmoooore]

No diversity allowed on instant water heaters, so the official answer is no, it won't be compliant if both showers can be used at the same time.