I have a customer that wants to switch there paddle fan/light combo with 2 switches at each entrance to the room(so that the fan or light can be switched separately at each entrance)I have never seen this done.If I use a 14/2 and 14/3 for travelers and neutral between switch boxes and feed 1 end and take a 14/3 to the fan/light combo does this meet code? The 14/3 will be used for travelers and neutral and the 14/2 for the other set of travelers.What do you think? Any other way to do this?
I'd start by asking what there is now. Fan box already installed? Is it fed always hot? Or are you starting from a wall switch?
If this is a new installation, the best method is to feed the first switch via a 14-2, run a 14-3 between switches, and a 14-2 from the second switch and the fan.
There are several other ways to wire 3-ways, too. Again, it depends on the present conditions and the wire-routing pathway. Tell us more.
nothing wrong with that at all....you MUST mark the white in your 14-2 traveler as a hot.
MI, are you sure about that? The end result is that the hot and neutral for one of the circuits are in different cables.
So, how close together would those cables have to be? Would it be OK for them to run around opposite sides of the room? I don't think so.
The problem is that the fan has only one neutral connection for both the fan and the light. Therefore you'd have to start with the 14-2 branch circuit to the fan box to make the neutral connection. Then run ONE 14-3 from the fan box to the first switch box (hot, fan, and light), and continue with TWO 14-3 to the second switch box (each having a hot and two legs).
Make sense?
I think the easy answer is to run the 4 travellers in a piece of Smurf tube between the switching locations. Then wire count is not an issue. 14-2 into the first one, 6 wires (5 current carrying plus ground) in the smurf to the second switch location and 14-3 out to the fan/light.
You know John that is correct, I never thought of it that way, our company had wired a certain model of a house in the same way....not for fan though, and the inspector never said a word. He could just run twin 14-3's and tie the neutrals in at both ends!
John, why is that an issue? A switch leg has no neutral either.
MI, you can't just tie the two neutrals, either, because the current will be divided between them, and only half of the current will return in the same cable as the hot leg.
poorboy, you're correct that a 3-wire cable with 2 switch legs and a hot (or load) wire has no neutral, but there is still an equal current in both directions -- "out and back".
We're all familiar with the requirement for the hot and neutral to be carried in the same conduit to prevent inductive heating of the metal. A more general statement of that requirement is that any current-carrying conductor has to be closely paired with another conductor carrying an equal and opposite current. The intent is to produce a net magnetic field of zero, whether the conductors are in conduit or in open space.
The code doesnt require a neutral in romex if I remember right. But I don't do residental.
For _non-metallic_ wiring systems, I do not belive that there is a _requirement_ that all conductors travel in the same raceway/cable assembly. At some point one hits performance requirements, such as having a low impedance fault current path...but you would have to have a pretty extreme situation for the inductive impedance of the loop to make a difference.
IMHO it is a very good idea to minimize loop area, for example to minimize 'emf' (no proven dangers here, but why go out of ones way to make a potential threat worse when doing things right essentially eliminates the issue). But I see no significant difference between running a _non metallic_ 14-2 and 14-3 side by side, versus running a single 14-5. The junction boxes would either need to be non-metallic, or both cables would need to enter through the same cable clamp (using a clamp suitable for two cables).
I am in total agreement that for metallic wiring systems, the inductive coupling to the conduit or cable armor is a significant problem, and that this would be a code violation.
-Jon
If you really insist on doing this with romex, split out the neutrals in the fan/light and run 2 14-3s.
winnie: "For _non-metallic_ wiring systems, I do not belive that there is a _requirement_ that all conductors travel in the same raceway/cable assembly."
Yes, there is: 300.3(B)
gfretwell: That occurred to me, too, but it might not be acceptable to the AHJ. A lot of fan/light combos are connectorized, and separating the neutrals would require modifying the factory wiring.
Every fan I have seen had the light as
an optional add on so there is a wirenut splice in there available to the installer.
I don’t see why this installation is so complicated. Use John’s method above (not my first choice)or bring the feed and switch legs to the fan in the same switch box. Then run 3 wire cables to the additional switches.
Greg, I agree that almost all fans have provisions for light kits but they use the same white wire as the fan. I don’t think I have ever seen a fan that has 2 white wires in the canopy.
Curt
John, keep reading, until you get to "unless..." and to 300.3(B)(3).
gfret, that would require adding another wire from the fan's switch housing to the ceiling canopy; definitely not easy, and maybe not permissable.
How hard can it be to shove another wire down 6" of 1/2" pipe?
Bear in mind my first choice was to run a raceway (smurf) between the switches.
Why would a raceway be needed between the switches?
If he puts in a raceway he could run 4 travellers, a neutral and a ground, making this something that is more than "hold your nose" legal.
There are plenty of inspectors who would question this "travellers in 14-2 romex thing. You probably win in the end but you still get mud on your clothes.
If you bring the feed and switch legs to the same box with dead end 3-ways this installation if perfectly legal. There is no reason to bring the grounded conductor to a dead end switch. Using this method 3 conductor cable should be used for each switch.
before you go through the trouble, do they make a 3-way fan speed control?
nevermind
http://www.prolighting.com/ludvdi1prfan.html [This message has been edited by Jps1006 (edited 07-09-2005).]
Cas Elegant solution I agree.
14-2 in, down and back to dead ends with 2 14-3s and a 14-3 to the fan/light.
Larry: You're right, I stand corrected. I skimmed exception 3 and thought it referred only to single-conductor cables. I'm still a little surprised it's allowed for NM.
caselec/gfretwell: Agreed. The hot pair can enter either the fan box (my example) or the switch box having the fan cable (yours). I like your way: it saves having to reidentify the white wire in the fan cable. Clean.
Interesting thread. Good solution, Cas. When we have these discussions at work they don't always stay this amicable. Everyone wants to be right. This is a great site for those of us who want to find the best way to do things in a friendly discussion.
If you really want this to be nice for the next guy, reidentify the black in one traveller set to red and the red in the other set to black, then mate them to red and black in the fan cable. (reidentified white is always the hot in a switch leg).
It would then be easy to sort this out in 10 years.
I agree with Cas.
Feed the circuit at the one of the switch boxes, then run a 3-wire switch leg to the fan, then run (2) 3-wire dead ends to other switch box.
The simpler, the better, IMO.
2002 Code: 300.3B All conductors of the same circuit and, where used, the grounded conductor blah blah blah shall be contained in same cable.
The key words "where used" might apply to dead-end switch legs and travelers. Unless I'm reading wrong, grounded conductor not used at dead-end switch legs or back-feeds doesn't have to route with hot conductors.
OR
are they refering to 240 volt applications,neutral not needed versus 120 volt circuits where neutral is needed.
Tom
just dead end both three ways to make it simple. feed and switch in one box and bring two three wires to the othe box one for the lite and one for the fan.