Busbar chamber cable sizes

[Shorne]

I’ve been asked to install a dedicated 32amp 3 phase supply for a passenger lift and need to tap off a 200 amp rated busbar chamber. The incoming supply to busbar is 200amp with 120mm SWA. Can I tap off this busbar with 10mm tails to a new 32amp switch fused isolator mounted to the side of the busbar chamber to supply the lift or do the tails have to be rated the same size as the 200amp incoming supply.

 

[Andy78]

You can install your first plan if it complies with 433.2.2.

 

[Shorne]

It would comply as the tails from the busbar to the isolator would only be at least 300mm in length