3 phase installation

[sparky marky]

Hi all, I am currently installing a 3 phase supply to a new building. The supply is taken from an adjacent building where I have tail blocked the 3 phases and neutral coming in after meter and run a 25mm 4 core swa via a 63A rotary isolator (run is 28m). Supply is TNCS

The new building requires 3 phase downstairs for the garage/workshop and I have run a 63A supply off one phase to supply a 17th edition consumer unit to supply the flat up stairs. The customer is to be living upstairs and use the workshop downstairs for himself requiring various 3 phase supplies (16A/32A), a ring main and lighting circuit.

My first question is should I supply RCD protection for the workshop to comply with regulations? If so how is this best achieved on the 3 phase board?

My second question is regarding the earthing required.. I have installed an earth pin at the moment connected to the 3 phase board, should I rely on this for both the 3 phase board and flat consumer unit? or use the armoured sheathing to supply earth to the 3 phase board and use the pin for the flat's consumer unit?

Any advice will be much appreciated

Thanks

Mark

 

[Sidewinder]

marky,

What is going into the workshop?

Wood equipment?

 

[Evans Electric]

Whats an earth pin ?

In the workshop I'd fit an RCD to the sockets only TBH.

 

[Sidewinder]

Deke,

RCBO on the s.o. is a good shout depending on what is going into the shop though.

 

[sparky marky]

Cheers that's what I felt consciously. The workshop will be mainly wood works yes, and by earth pin I mean stake! Only one and the reading is above 200ohms so i'm looking at putting 1 or 2 more in the try and get the reading below 100ohms?

 

[Sidewinder]

If its wood then all ccts need to be on at least a 300mA rcd

 

[Riggy]

Sidewinder: is the RCD requirement for woodworking machinery a regulation or your view?

 

[philbas]

It's in the regs,

422.3 Note 1 specificaly defines woodworking facilitys as a location with risks of fire due to the nature of processed or stored materials and 422.3.9 requires this location to be RCD protected.

 

[Riggy]

Philbas: thanks for that.

 

[philbas]

Philbas: thanks for that.

Your welcome, you can clearly use the exceptions to 422.3.9 to avoid the need for RCD, but from your OP I suspect this is not really an option . Much cheaper just to put the RCD in.

 

[Sidewinder]

philibas,

Thanks for that, as usual no regs book to hand.

External inluence BE2. Enhanced risk of fire due to the nature of processed and or stored materials.

Can never remember the number but can quote the wording, it was also in the blue & brown books, not sure about before that!

 

[philbas]

Blue & Brown I dont know, I was bought up on red . and only just passed that last week