three phase domestic application

[sparkticus]

Good evening good people, I have been asked to quote for installing a commercial size Ironing Press in an outbuilding which adjoins a dwelling. The press requires 3Ph&N. I would consider the outbuilding which has a door directly into the main kitchen as a domestic environment (laundry room)

There is an adequate 3Ph&N TN-C-S supply just the other side of the wall so I am thinking of installing a sub-main (tails > 3ph switch fuse >4core SWA >CU > Iron/Press)

I have in stock a 3ph CU with three pole incomer and three pole RCBO. But what about the neutral in a domestic situation? Surely it does not need to be switched? or does it?

thank you

 

[RF Lighting]

No it will not need to be switched.

Can't you take a supply straight out of th existing DB?

Does the new supply really need RCD protection? TP&N RCBOs cost a fortune.

 

[sparkticus]

Thank you RF Lighting for your rapid reply. I'll be honest and say that I am not an expert with domestic applications. My son is but he is getting himself some UV down in Palermo at the moment. The press is fixed equipment but I was thinking it would be good practice to fit an RCBO (or RCD) in such an environment (the fact that I have the RCBO on my shelf made the idea come to mind)

Unfortunately there is no other 3ph board. The existing 3Ph intake is split out into multiple, small single phase boards/switch fuses etc.

 

[RF Lighting]

Ah right I see. In that case you'll have to like you say either fit a TP&N DB or switch fuse at the intake and supply an isolator local to the machine with SWA

Personally I wouldn't RCD protect the circuit unless there was some specific reason to do so such as a manufacturers requirement.