- Jan 30, 2021
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- If you're a qualified, trainee, or retired electrician - Which country is it that your work will be / is / was aimed at?
- United Kingdom
- What type of forum member are you?
- Practising Electrician (Qualified - Domestic or Commercial etc)
Morning all,
I’m scratching my head with this and granted I don’t do a lot of commercial work. Hence I thought I’d ask.
Setup is a pub with a 3ph supply and it’s TT
So it goes
Incoming head - 3 x 100a cutout
Meter
3 pole isolator for L1, L2 & L3
L1 to single phase into plastic DB
L2 to single phase into plastic DB
L3 to single phase into plastic DB
Neutral into a Henley then to each single phase DB
However my understanding is that with a TT system it must be a 4 pole (TP&N) isolator? Only TNS & TNCS don’t need to have the neutral isolated.
Is there any reason why a TT system would be able to have an exception? I’ve no previous paperwork to look at to see a reason why.
Advice appreciated before I go back to them to tell them they need a 4 pole isolator.
I’m scratching my head with this and granted I don’t do a lot of commercial work. Hence I thought I’d ask.
Setup is a pub with a 3ph supply and it’s TT
So it goes
Incoming head - 3 x 100a cutout
Meter
3 pole isolator for L1, L2 & L3
L1 to single phase into plastic DB
L2 to single phase into plastic DB
L3 to single phase into plastic DB
Neutral into a Henley then to each single phase DB
However my understanding is that with a TT system it must be a 4 pole (TP&N) isolator? Only TNS & TNCS don’t need to have the neutral isolated.
Is there any reason why a TT system would be able to have an exception? I’ve no previous paperwork to look at to see a reason why.
Advice appreciated before I go back to them to tell them they need a 4 pole isolator.
