Does US electric code allow branching ?

[Externet]

Hello.
My energy meter feeds the 'loads center breaker box' with 20 feet of conduit.
Would like to tap/connect another short branch from the same meter out to a second box 4' nearby with another conduit. Is that allowed ?

Meter 240VAC out==================================================100A multi breaker panel
               \======single 30A breakerbox

 

[rjenkinsgb]

I'm not in the USA, but I very much doubt that is permissible.

The safe way to do it is add a 30A circuit from the existing distribution board, so the protection of that is handled by both the main breaker and the branch output breaker.


Whatever you add to a mains system must be capable of both handling and breaking the full current from whatever feeds it.

ie. Anything feeding from the meter must be capable of handing fault currents in case of a short.

The upstream system (pole transformer etc.) will have fuses to protect the cable feeding the meter and through to the 100A distribution board.

The extra branch would need the same ratings, so the cable cannot overheat in case of a fault, and have an incoming breaker rated for the same fault current as the one in the main panel. They have to break the worst-case fault current, which may be thousands of amps for milliseconds, without any possibility of the contacts welding rather than opening).