I have to run 4 new circuits for a kitchen I am helping to remodel for a friend of mine
1-Fridge 1- Microwave/Range hood 2-counter outlets ( as required by code I was told)The runs from the kitchen to the panel is very long and I also have to drill through several ceiling joists. I was thinking of running 2-12/3 cables instead of 4-12/2 cables. Is this allowed by code? I think someone mentioned for the counter outlets is fine, but I'm not sure about the fridge and microwave.
But don't you have to gang the breakers for the outlets and/or the fridge/micro, if you wire it like that? Kinda defeats the purpose of having separate strings, methinks. Plus, 12/3 is a lot harder to work with, and stuff into boxes. I'm no code wizard, but IIRC, you have to maintain both hots all the way to the end of the string, and are not allowed to split the neutral and head 2 different directions. But I could be wrong- somebody will be along to correct me momentarily.
I can't remember- how big does the hole through a joist have to be, to pass multiple 12/2 feeds through it? I'd go that route if you can.
And on general principles- even if something 'odd' is code legal, or barely so, it will confuse the poor SOB 20 years from now working on it. Best to keep things as simple and self-evident as possible.
I remeber reading that if curent to/from device is in one conduit, the EMF will not create induction heating. But your case will because at least one of your wires is sending in one conduit, and the return is in the other. I'm sure the bonafide electricians out there will clarify.
If you insist on drilling less holes, you'd be better off with a couple runs of 12/2/2. You'd have a proper neutral for every circuit that way. You have issues sharing neutrals with GFCI outlets.
For a kitchen, where AFCI circuits are not required it is perfectly acceptable to do what you propose. You do have to connect them to double pole breakers, so both circuits are opened simultaneously.
When it's a long run, it makes sense to use a 3 wire. You just terminate it in a big ass box. It is a bit annoying to have to use a double pole breaker, because you can't just shut down one circuit, but the idea is to prevent miswired Edison circuits, which can be a fire hazard.
Thanks for everyone's input. I might just play it safe then and just run seperate12/2's.
Now to another subject without starting a new thread: is there a certain guidline on where to drill holes in 2X8 joists? Can I feed
2-12/2 romex's into one hole? How big of a hole can I drill?
Microwave/range hoods use a lot of power. Mine uses 1500 watts. Should that have it's own neutral? We put ours on a single 14/2
A 3/4" hole at least 2" from the edge of the joist is fine for 2, 12/2 cables
RBM is right on point. Another advantage to the multiwire circuit (what you call this) is reduced voltage drop. The only thing you have to do is split out two neutrals at the kitchen end so you can hook up the GFCIs. You will need a big box for that. I usually gang both GFCIs in a deep 4x4 box there so you have 4 outlets and then go to the down stream outlets from there. On a counter, you never seem to have enough outlets so I like quads all the way down, at least in the places that will accumulate appliances.
Should be far enough down from the floor. That some future worker doesn't puncture the wire with a nail from above.
But in this case the GFCIs don't know anything about the neutral being shared because they are connected downstream.
The OP says that it is a "very long" run, but not how long. If it is really long, a sub panel might be the answer to keep voltage drop down. It might make sense, especially if there are other possible additions in the future.
By my count you have 3 circuits. Are 2 circuits for the counter top required by code now?
ok, go ahead and try that.
That is what I meant above. 2 seperate circuits for 2 counter outlets. I was told this is code.
have been for many a year.
Way bigger than you need for four 12/2. Some electricians drill more and smaller holes, but I think that's primarily because they lost the chuck key and don't want to change the bit.
It is allowed, and it will give you a slightly better performing installation than running the 4-12/2 cables. [Less voltage drop, less use of resources (copper), marginally smaller holes in the floor joists.] However, as you can see from the variety of responses, it is also confusing to many people, so that may be an issue.
The only downside is that you will need to use a double pole breaker or a handle tie with two single pole breakers on opposite phases. Once you arrive at your destination, you can split the 12/3 into two separate 12/2 circuits as desired. This will in fact be necessary downstream of any GFCI receptacles.
Cheers, Wayne
The best place for holes in a joist is at the neutral axis where the joist is only stressed in bending. What this means in practice is to stay away (maybe 2 feet?) from the bearing points (over and under wall framing) and then to put your holes in the middle of the joist.
Yes, in fact if you would find it easier, you can feed all four 12/2s, or two 12/3s, without any problem NEC-wise.
The maximum size hole you are allowed to drill is quite a bit more than what you will need, e.g. a 1.25" hole for 4 12/2s would be fine.
Cheers, Wayne
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