While doing some DIY remodeling, I came across a double switch box containing switches from 2 different circuits. Knowing some of the history of the house, and previous remodels, I can see a logical reason of how this came to be…..but it seems to me that this is possibly a code violation. Certainly, one has to be aware to kill two circuits before working in that box, or risk an inadvertant shock. I’ve corrected the situation, but a co-worker who ‘knows’ about all things electrical says there was no code violation. Was I just being too cautious, or was this unsafe? Thanks
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From my admittedly mediocre knowledge of the code, I believe your friend is right. I don't know of any reason why this would be disallowed assuming the installation was done correctly. Besides which, I always (from past shocking experiences) test every conductor before reaching into a box.
Not everything allowed by code is a good idea.
Not everything that codes DON'T allow is a bad idea.
It is not a code violation to have two circuits contained within one outlet or switch box if the system is 240/120V. If you are working on a commercial site and the system is 480/277V, then you are required to have a partition barriers between the devices.
The danger or working in an electrical box with more than one circuit is that you could come in contact with 240V or 480V (depending on the system voltages) by touching phase to phase.
As always when working on an electrical system, shut off the breaker and don't risk your safety on a light switch that can accidently be turned on, and always test the circuit with a voltage tester.
As far as I know this is not a code violation that would upset a building inspector. BUT, this is a major violation of MY building code.
That is not a code violation.
And if you look at the "big picture" and open houses it would be impossible to have all every box only have wiring from one circuit.
If that was the case then all of these lights in my house would have to be on one circuit.
Front door
Switched recept & can's
Accent cans (both on 3 ways to other side of living room)
Outside light
3/4-way "hall area" (pathway in open plan) lights.
Side door
3/4-way "hall area"
Dinning area light
Outside light.
Bottom of stairs
3/4-way "hall area"
3/4 way stair lights
Stair landing
3/4 way stair lights
Basement lights
Top of stairs
3/4 way stair lights
hall light
3-way upper stairs light
Upper entrance/garage
3-way upper stairs light
3-way garage light
Garage door
3-way garage light.
And by each of the outside doors (and a few other that I have not mentioned) there are low voltage remote relay system controlling more outside lights.
If those where on regular switches they would be in the same box as the other switches and about double the number of lights that are combined in those boxes.
And there are "mutli-wire" circuit where 3 wires are run 2 hots (on different legs) and a shared neutral. Unless both hots are on the same device (receptacle in most cases) it can be fed by 2 single pole breakers.
Anyone qualified to be working on electrical wiring has a voltage detector. They do not require contact with the conductors, and are available in any box store or hardware store. No need to get shocked.
Thanks all for the info. So I did a little more work than I needed to, it seems, fixing something that wasn't broke.