2 circuits, one swithbox

bjherron

assuming I don't have too many wires in a switch box, can I have two different circuits entering and leaving the box without violating any codes? I'm new to this, and I thought I would ask before I wire a bunch of switch boxes this way.

jbfan

Yes you can. Tie all the grounds together, but keep the neturals seperate for each circuit.

I just saw that you were going to wire a bunch of boxes this way. That could be a waste of wire and time.
I would consolidate circuits

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frenchelectrican

I will echo Jbfan's comment.,,

I do the same way it done that few time IMO it far much easier if you can get all in one circuit if possible if not just rember if on sepreaed circuit keep the netural seprated sometime it will be wise idea to mark down the wires what circuit it goes that will give them a hint or forewarn that is seprated circuit there.

this what i useally do if have seprted circuited not the MWBC type this way what i useally do is marked the netural with a marker or tape so i know not to tie to other netural so it dont affect the other circuit at all

Merci , Marc

Tool Junkie

If you havnt run the cable yet you can run a 3 wire cable and share the netural. Keep in mind the the breakers need to be next to each other so you can connect the switches together (via the holes on the breakers handles) as if one trips it is required (code) that they both trip.

HouseHelper

Just so you can keep your facts straight, this is what I said in another post:

"The handle tie is only required if the two circuits share the same strap, i.e., the two receptacles of a duplex receptacle split between the two hots with the neutral common.

It should be noted that this handle tie is present so that the breakers can be turned off together, and can be achieved by using a double pole breaker or two single poles with an approved handle tie. If using two single pole breakers, they may not both trip in the event of a short circuit since there is not an internal trip mechanism present."

fw2007

Interesting and very helpful info!
I have a situation where previous owner used 12/3 BX into an outlet box, then ran another circuit from there upstairs. Share same neutral, but the breakers, although next to each other are not bonded.
Makes lots of sense to have breakers trip together for safety, but as I understand, as long as the breakers are next to each other (on opposite sides of the 220V line) there is no problem sharing the neutral, as the net current in the neutral wire is (theoretically) the difference between the circuits, not the sum. Would be a problem if one of the breakers is GFCI though!!

FW

fw2007

Woops! Should have read all of the replies before posting. I didn't see the last one about the tie-bar required only if the 2 circuits are wired to same duplex receptacle.
So I guess mine is OK, as long as the two breakers are still next to each other.

FW

Andy in ATL

I think it is changing to be a requirement for ALL multi-wire circuits to have a handle tie in 2008. It is wise and a common practice to handle tie MWBC even when it is not code for safety. For that matter, I only put MWBC in commercial settings and never in houses...Safety first!