Shared Neutral (not borrowed) 3 phase

[binky]

I'm glad there's finally sdome actual regs given for consideration, thanks SW.     ***edit*** where's the scoob button gone by the way?

My copy of the UK regs is several ammendments behind current but here's another one for consideration. RCD protection built into the socket outlet would be only supplimentary protection and wouldn't fulfil the requirement of disconnection of all line conductors.....

531.2.1
RCDs
An RCD shall be capable of disconnecting all the line conductors of the circuit at substantially the same time.

it would disconnect the appropiate phase, but you wouldn't expect an RCD socket to be 'dead' just tripped out.

 

[M107]

I can give a real life example of this scenario in place in our old IT equipment room (soon to be demolished)..

30amp TP C50 supplying TPN to an isolator each phase then feed the following L1 = Aircon L2 = 3x double sockets L3 = 3x double sockets + another DP isolator for a UPS.

This was picked up on  periodics over a 16 year period as Code2 but due to not being able to isolate the circuits it got left.

 

[Lurch]

I suppose it depends on why this question is being asked. It works fine, electrically. I'd have no problems having this running like this in my garage but it's one of those things that if something happens and someone says 'that's not right' you have no leg to stand on. Being commercial/industrial there is a lot of arse covering.