same light switch box, different breakers?

[Howie]

Is there any electrical code violation in having two light switches in the same electrical box, but the switches originating from different breakers?

Howie

[Greg]

nope

[Howie]

so it's ok?

[Greg]

Yes you can have more than one circuit in a single box. The only time you have an issue is when they end up on the same device. Then they have to be on a common trip breaker. An example is where you have two circuits sharing a common neutral (AKA multiwire) and feeding the top and bottom of a duplex receptacle. In that case they must be on a common trip 2 pole breaker. If they are not on the same device there is nothing special about them.

[Howie]

Greg,

Thanks for the advice!

Howie

[MC]

Is this for all states? I never remember seeing this in our code, Just I need to go back and look but it has been a while since I did any electrical for hire, just myself these days. I had thought duplex outlets could be wired on individual trip breakers. Seen many kithens around here that have each side of the duplex outlet wired to different breakers but the breakers are not dual poled?

If know where in the code I can go look up I would appreciate, Don't want to do it wrong in case come accross this later.

[Greg]

NEC 2002

210.4(B) Dwelling Units. In dwelling units, a multiwire branch circuit supplying more than one device or equipment on the same yoke shall be provided with a means to disconnect simultaneously all ungrounded conductors at the panelboard where the branch circuit originated.

[PrecisionMachinisT]

Personally, in such cases I avoid having the feeders coming from opposite

110v legs, as this puts a 220v potential inna box where someone would usually expect to only find 110v.......

So I would suggest it would probly be best if these two breakers were plugged into the same 110v buss within the service panel.

[Mike Fritz]

This is the case for the kitchen in my house. The kitchen is on a 3 way switch. The light is wired through the circuit that contains one switch. The other switch is in a box with 3 other switches, and they are one a different breaker.

--Mike

[Doug Miller]

No.

And for the life of me I can't figure out why. It seems to me that this is a

*very* dangerous situation, because there is *no* way to know that a second circuit is present in the box. AFAIK, the code doesn't even require the box to be labelled in any way. [Yes, I know that the code does require the branch circuits to be labelled at the panel. And we all know that every panel is properly labelled. Yeah, right.]

[Chris Lewis]

According to Howie :

In Canada, yes.

In the US, no.

[HorneTD]

It can be a code violation in the US also if the lights involved are 277 volt fixtures such as those used in larger office buildings. There is, however, a simple solution. Use a four square box with a plaster ring to mount the two switches. The plaster ring and box combination will accommodate a divider that will convert that one box into two without preventing a two gang plate from fitting on the two switches. Multi gang boxes up to six gangs are available through supply houses with plaster rings that will accept multiple dividers.

-- Tom H

[Terry]

Thanks Chris: Cos last year when I added a switched lighting circuit in a second metal box which I ganged onto to an existing box and switch at bottom of our stairs, I made sure it was energised from the same lighting circuit breaker. Seemed like the most logical and safest to me? Terry. Eastern Canada.

[Chris Lewis]

According to Terry :

It certainly is the safest approach. The only times I've _ever_ been bit is from times where professional electricians have violated this rule.

[Once in our current house, and once in a large apartment building.]

[Chris Lewis]

That "out" is also available here, but, it's probably not invoked too often because of nuisance/"oddball bits" factor.

I don't bother - if I can't get the two switches on the same circuit, I sling the second switch in a box on the other side of the stud.

[HA HA Budys Here]

Not uncommon, especially during the insatiable hi-hat craze of the 80's to have a 3 or 4 gang box fed with a 14/3 homerun with 2 or 3 switches on one circuit and 1 or 2 switches on the opposite leg of a 3-wire 240 volt homerun.

In addition, practically every homerun was done with 3 wire cable. Many electricians liked to HR to the area smoke detector (which were not interconnected at the time) as a rule of thumb, and split off to 2 - 2 wire circuits from there. But others made it a habit to bring all homeruns to a switch first, feeding out with a 14/2 to area convenience outlets, and a 14/3 to bring the other circuit and switchleg to the other circuit convenience outlets.

It is also common to bring both kitchen circuits to the refrigerator outlet and split off to 2 circuits from there, as well as 2 circuits to the disposal switch, and split off the dishwasher circuit there.

Finding 220v in a switch box is not at all uncommon or dangerous.220v is no more "dangerous" as 120v if you don't know what you're doing, and the nuts & bolts of wiring a home don't, and shouldn't have to take "homeowner DIYer might not understand this" into consideration.

[HA HA Budys Here]

Up to 12 gangs for a roughouse box :-)