This discussion is locked.

You cannot post a reply to this discussion. If you have a question start a new discussion

Unfused busbar tap-offs

Good afternoon.

I have a hotel where the consumer units of each room are fed through a 63A horizontal busbar using tap-offs along the way.

In the past the norm was to used 32A fused tap offs for each CU. The cable to each CU was rated at 32A as expected.

Could these tap-offs be unfused and the cables feeding the consumer units be rated at 63A ....same as the busbar?

Is this contrary to any regulation?

Thank you

Already registered? Log in and reply

Parents

0 Former Community Member over 6 years ago

Provided you can accept the possible loss of discrimination (a fault on any consumer unit tap off will kill off the busbar) then provided the busbar infeed cable, the busbar itself and the tap off outfeed and consumer unit rating all meet or exceed the rating of the OCPD, then happy days

Keep in mind that this is exactly the scenario that leads to small overloads of long duration - so be reasonably generous with the cable sizing against whatever diversity you've applied to the busbar loading in relation to the room loads

Regards

OMS

Reply

0 Former Community Member over 6 years ago

Provided you can accept the possible loss of discrimination (a fault on any consumer unit tap off will kill off the busbar) then provided the busbar infeed cable, the busbar itself and the tap off outfeed and consumer unit rating all meet or exceed the rating of the OCPD, then happy days

Keep in mind that this is exactly the scenario that leads to small overloads of long duration - so be reasonably generous with the cable sizing against whatever diversity you've applied to the busbar loading in relation to the room loads

Regards

OMS

Children

No Data

Unfused busbar tap-offs

Community Rules & Guidelines