Sorry, appear to have opened a can of worms.
My understanding of the NEC is that you can have two branch circuits that share a neutral if your disconnect means will disconnect both at the same time. Otherwise you could have current flow in the shared neutral after a tripped or shut off breaker. The simple way to do that is a handle across two breakers, or a two pole breaker.
The do it because it saves a bit of wire (one 14-3 instead of two 14-2 runs), which to me is dumb, dumb, dumb... but not illegal.
To the issue of multiple branch circuits in one box I know of no restrictions on that, and it is really common, especially in more complicated houses where you might have many switches in one box. In my last house, for example, dock lights were switched from indoors -- but the dock had its own sub-panel outside. The switched wire was run back into the house and back out, with no neutral in that box at all.
If multiple branch circuits make use of a neutral in the same box, and are not a multi-wire branch circuit with common disconnect, then each neutral must be kept separate and never tied together or mixed up.
Multiple branch circuits in a single box is otherwise known as "homeowner wiring discouragement" which is applied via a shock when you only turn off one breaker. :blush:
If curious I can probably dig up a NEC and look up the code section for multi-wire branch circuits. The other is harder to find as it's a matter of lack of reference, since I do not think there is anything to prohibit two circuits in a box. I doubt it says "you can put two circuits in a box". But maybe.
My understanding of the NEC is that you can have two branch circuits that share a neutral if your disconnect means will disconnect both at the same time. Otherwise you could have current flow in the shared neutral after a tripped or shut off breaker. The simple way to do that is a handle across two breakers, or a two pole breaker.
The do it because it saves a bit of wire (one 14-3 instead of two 14-2 runs), which to me is dumb, dumb, dumb... but not illegal.
To the issue of multiple branch circuits in one box I know of no restrictions on that, and it is really common, especially in more complicated houses where you might have many switches in one box. In my last house, for example, dock lights were switched from indoors -- but the dock had its own sub-panel outside. The switched wire was run back into the house and back out, with no neutral in that box at all.
If multiple branch circuits make use of a neutral in the same box, and are not a multi-wire branch circuit with common disconnect, then each neutral must be kept separate and never tied together or mixed up.
Multiple branch circuits in a single box is otherwise known as "homeowner wiring discouragement" which is applied via a shock when you only turn off one breaker. :blush:
If curious I can probably dig up a NEC and look up the code section for multi-wire branch circuits. The other is harder to find as it's a matter of lack of reference, since I do not think there is anything to prohibit two circuits in a box. I doubt it says "you can put two circuits in a box". But maybe.