Adding new circuit to CU

[mrscalex]

Is it sufficient to just turn off the master switch at the CU when adding a new circuit/MCB? I'm thinking it might accidentally get knocked back on.

Thanks.

 

[andy]

Is it sufficient to just turn off the master switch at the CU when adding a new circuit/MCB? I'm thinking it might accidentally get knocked back on.

Thanks.

safe enough. there pretty hard 2 'accidently' turn on

 

[Lectrician]

Remember the supply into the isolator will remain LIVE

 

[ban-all-sheds]

Is it sufficient to just turn off the master switch at the CU when adding a new circuit/MCB? I'm thinking it might accidentally get knocked back on.

Thanks.

safe enough. there pretty hard 2 'accidently' turn on

D'you remember the days when you couldn't turn them back on until the cover was back in place?

Maybe there's something to be said for CUs where the main incomer is not just another modular device on the rail, but an integral part of the body, so that you can have a mechanical interlock.....

 

[plugwash]

im sure on the old wylex standards while you couldn't (easilly) get the lid off with the switch on you could definately turn on with it open

also modern CUs are intended to be safe for competent persons (IP 2X) with the lid off

how else do you propose to do things like earth loop tests on them?

would always advise taking great care when opening a CU that you haven't touched recently for the first time though in case someone didn't do a very good job of tail termination

 

[ban-all-sheds]

They could be designed with further access covers to be removed, and a safety interlock that could be overridden by a deliberate action.

It was just a thought that maybe the design ought to be that you can't accidentally or unthinkingly turn it on with the cover removed, but I guess with Part P on the horizon there's no incentive for manufacturers to produce dork-proof CUs....

 

[ban-all-sheds]

also modern CUs are intended to be safe for competent persons (IP 2X) with the lid off

Things could be worse - we could live in the USA:

 

[AdamW]

I really hope that pictured CU isn't for a whole house... no way are those conductors out of the breakers meaty enough... ESPECIALLY not at 120V.

Is there a cover that fits on, leaving the breakers available? Only the "Service Wire Lugs" are right where your hand will be when you try to flip on the main breaker! Perhaps some kind of clip-on plastic cover is in order for the terminals? Designed so you can't get anything in there with the covers in place.

Do they call them CUs over there or is there another name for them?