three phase advice for newbie

[DavidWick]

hello,

I am after bit if friendly advise on 3-phase as don't have a lot of experience with it.

3-phase + N supply being fitted to a existing site as there is going to be a very large demand with house, outbuildings and swimming pool. the main intake and 3phase meter is in garage that is separate to house and outbuilding. there will be a 3phase consumer unit above meter to feed consumer unit in each outbuilding and the house

Client will have requirement for 3phase for some machinery in one of his workshops so this eliminates option of treating install as 3 separate supplies with 3 consumer units.

how do you go about getting just a single phase to house from a 3phase board- considering the load - as obviously mcb not large enough so would need to be main switch? if so do they do single pole? or do you use triple pole switch with only one tail exiting it (cant imagine that would be right??)

Sorry if obvious answers but cant say its something I have ever covered.

cheers

 

[Lucien Nunes]

Use a panelboard with MCCBs so that you can have an outgoing circuit large enough, or split the supply to a separate fuse-switch before the local DB.

 

[DavidWick]

ive not fitted an mccb before, they take just a single live cable much the same as an mcb then? but they fit across all 3 ways/modules like a triple pole switch would?

Would that be the way you would recommend? obviously after safety, want it to look neat that is why originally I had in my head a large 3phase dis board in garage then armoured from that board to each outbuilding with standard single phase CU in house etc.. but I thought about breaker to use to feed submains and wasn't sure what to use as needs to be 100amp really.
out of interest could a triple pole mcb with singe cable exiting it be used or is that a big no no?

thankyou

 

[Leesparkykent]

You don't want to be feeding the distribution circuits with an mcb as you will get little to none discrimination. In your situation I would probably install a ryefield board to feed the distribution circuits.

 

[DavidWick]

what would you recommend leesparky?

thankyou

 

[Leesparkykent]

what would you recommend leesparky?

thankyou

A ryefield board. https://www.sparksdirect.co.uk/elec...its/industrial-and-commercial/ryefield-boards

 

[davesparks]

ive not fitted an mccb before, they take just a single live cable much the same as an mcb then? but they fit across all 3 ways/modules like a triple pole switch would?

Would that be the way you would recommend? obviously after safety, want it to look neat that is why originally I had in my head a large 3phase dis board in garage then armoured from that board to each outbuilding with standard single phase CU in house etc.. but I thought about breaker to use to feed submains and wasn't sure what to use as needs to be 100amp really.
out of interest could a triple pole mcb with singe cable exiting it be used or is that a big no no?

thankyou

I would honestly recommend employing someone who knows what they are doing as these questions are quite worrying and it's impossible for us to teach you everything you need to know via a forum.

Your options are either a panelboard or busbar and switch fuses, but without the details of the supply and loads it's hard to recommend anything