I’m fitting a single-phase car lift in my own workshop.
New three phase sub-main panel 10m from the lift, 16A TP MCB (with TP 30mA RCD upstream) feeding car lift control panel the in middle of the concrete floor, via existing underground (non-ducted) 4c SWA.
Is it OK to mount the following on the control panel, without any additional, separate breakers?
L1 / L2 / L3: TPN red socket, with local TP switch.
L1 only: 16A industrial socket with local SP switch.
L2 only: 13A Switched double socket.
L3 only: The car lift itself.
It’s very useful to have a range of sockets local to the lift, without trailing leads across the floor.
I don’t want to use three separate SP MCBs in the DB because that would mean a shared neutral, with all the issues that brings. Additional cable runs are not possible.
I do want to have TP available at the lift for future-proofing, load balancing, and for the possible future exchange for a three-phase car lift.
It feels a clumsy design, but is it OK electrically?
An overcurrent fault of any one phase will kill the whole panel, that’s fine. An earth leakage fault on any one phase will trip the upstream TP RCD, killing the whole area. Not ideal but OK.
Ideally I’d use a 16A 3-pole RCBO, but such a thing does not appear to exist. I need to limit current to no more than 16A per phase for cable back-protection, as it’s a very long run of 10mm from the supply.
New three phase sub-main panel 10m from the lift, 16A TP MCB (with TP 30mA RCD upstream) feeding car lift control panel the in middle of the concrete floor, via existing underground (non-ducted) 4c SWA.
Is it OK to mount the following on the control panel, without any additional, separate breakers?
L1 / L2 / L3: TPN red socket, with local TP switch.
L1 only: 16A industrial socket with local SP switch.
L2 only: 13A Switched double socket.
L3 only: The car lift itself.
It’s very useful to have a range of sockets local to the lift, without trailing leads across the floor.
I don’t want to use three separate SP MCBs in the DB because that would mean a shared neutral, with all the issues that brings. Additional cable runs are not possible.
I do want to have TP available at the lift for future-proofing, load balancing, and for the possible future exchange for a three-phase car lift.
It feels a clumsy design, but is it OK electrically?
An overcurrent fault of any one phase will kill the whole panel, that’s fine. An earth leakage fault on any one phase will trip the upstream TP RCD, killing the whole area. Not ideal but OK.
Ideally I’d use a 16A 3-pole RCBO, but such a thing does not appear to exist. I need to limit current to no more than 16A per phase for cable back-protection, as it’s a very long run of 10mm from the supply.
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