3 phase electrics

Nov 18, 2004 7 Replies

I'm putting in a 9kw electric shower and a 9kw instant water heater in the kitchen. Have 3 phase so might as well put kitchen on one phase and bathroom on another. Is this problematic in any way? I know that outlets on separate phases should be well apart. BTW all temporary for 2 years or so while we carry on with our chapel conversion.



cheers



Jacob


Yeah. Give the water heaters a phase each, but have all socket and lighting circuits on one phase, assuming the premises aren't large enough to require a more careful design. I'd put 400V stickies on (or inside) the heaters to warn any sparkies.

Christian.

On 18 Nov 2004 07:07:18 -0800, snipped-for-privacy@jpbutler.demon.co.uk (jacob) strung together this:

Can't see a major problem with that. I'd put the heaters on a phase each and use the 3rd for all the power and lighting. I'd also make sure that the bonding is upto scratch in the property, and make sure the board is well labelled up and by\in the heaters themselves.

?????????? Why, the loads are single phase.

Because if two different phases come into contact there is a potential ~400 volt single phase electric shock hazard.

True, I'd be more inclined to label fuse boards prominently, but you could make a case for a not very alert sparkie doing something daft because he wasn't expecting 3 phase.

-- Malc

But surely the risk is away from the fuse board, most 3ph boards are rather obviously 3ph, a single phase termination at the load isn't obviously feed from a 3ph board and that another termination in the same area could be on another phase IYSWIM.

Yes, but the voltage between the sparky's tools (plugged into the main phase) and the appliance will be 400V.

Christian.

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