ECN Electrical Forum
Discussion Forums for Electricians, Inspectors and Related Professionals

I wonder if they are going to make 12-4 NM-B more readily available for the upcoming code change to prevent generating induced voltage by someone trying to mickey mouse a three or four way.

I have not encountered any problems obtaining NM with the necessary conductors. As I see it, all you need is a black, a red, a white, and a ground.

I will admit that you will need to run two cables to each switch - one 'in' and one 'out.' Again, I don't really see that as an issue with 3-way and 4-way switches; it really affects the ordinary switch, though.

Let's face it - we're going to have to get out of the practice of making the box above the fixture our "main" box. That's what the proposal changes. No more running a single cable from the fixture to the switch, and re-labeling the white wire as a switch leg. They want the feed to enter the switch, then go on to the fixture.

Good practice? Probably. Warrant becoming part of the code? I don't think so.

You already know this so to clarify, you can run to the fixture and then run a 3 conductor with ground to the switch. So this does make the switch first more likely and the likely way to run 3 and 4-ways and ending with the run to the light, otherwise the requirement for 4 conductor with ground. Just a bit more planning if you are not in a habit that already includes the neutral.

Shane

If I understand it right, a grounded conductor will be required to be pulled to eash switch. In a 3 and 4 way swith loop, three wires are required to run between the switches just to switch the hot leg. How to you get your a grounded conductor to the other switches without violating 300.3(B)? Violate 300.3(B) could likey generate some CEMF and FUBAR the electronics in the switches the new rule call for.

Not only the NEC is a safety manual. Its becoming a designing manual. By bringing a grounded conductor to each switch in no way makes the wiring any safer. It's a design issue. If shhh-poopheads are using the grounding conductor as a grounded conductor, the shhh-poophead will still do what he/she is doing til someone holds him/her to their actions.

Here's how you can do it:

Ordinary B/W/G Romex brings power to the first 3-way switch, then B/R/W/G continues to the 4-way(s), B/R/W/G to the last 3-way, then B/W/G to the lights. Between the 3-ways. you use the black and red as your 'travelers.'

What the rule eliminates - or at least makes impractical - is running simple switch legs to a junction box above the light. In effect, every switch box will need two cables to it - one 'in' and one 'out.'

I like the idea, but I don't like the rule.

Another option, if you want to keep doing the "big J box at the light" method is to drop smurf tube to the switching locations.
It is not the cheapest way to go but it does give you the most flexibility later.

Down the road, I wonder how many of these "neutrals" will be hijacked as current carrying conductors for additional switches or added 3 ways.

Someone once told me: Don't speak of it ... if it's good it runs away, if it's bad it shows up!

I just encountered a remodeling job - the guy wants to add a third switch to several 3-way light circuits. My first thought was to simply interrupt the travelers, then run a single 14-2-2 from that new j-box to the new new switch location (re-tagging the neutrals).

Well, under the 'run a neutral' rule, that short-cut is out; looks like I'll be running some more wire. Oh, Well!

Edit to add ... Since each room (for this project) has two levels of lighting, that means there will be two 4-ways at each location. Adding the neutrals and grounds means I need room in the box for 16 wires (plus pigtails, etc.) Let's face it; "switch" boxes and "stack" switches are now restricted as to your use of them.

Just run a single neutral and ground? If I was coming from a single j-box in pipe, I could do it. Since I'm using Romex, that's out - there's no form of Romex with 4 'hots,' 1 'neutral,' and 1 'ground.'

The "Law of unintended consequences" just kicked in.

Push a 1/2" smurf tube down there

One of is missing something. I understand that 2011 NEC will require a grounded (neutral) wire to be pulled to every switch. 300.3(B) requires that all the wires of a circuit be ran in the same conduit, raceway, or jacket. This is to prevent CEMF. doesn't matter how you slice it, you would need a minimum of 4 wires to run a 3 and 4 way between the switches. Running 2 NM-b is a violation of 300.3(B)

B/R/W/G ... Black, red, white, ground ... that' four wires. Two travelers, your neutral and your ground. That's all you need between the 3-way switches.

I see what you are saying now. Old habits are hard to break. Trying to make it work mu old way which saved time and material (rqual dollars saved). I can still do it my way, add one more 12/2 run and make sure I don't parallel my neutrals.

This has been my standard for years. However,there are times when I will just drop a switch leg.

How is it safer? Appears they are just making it easier for the DIY crowd. We have lost our last ally.

I've noticed a few references to 300.3(B). IMO, 300.3(B) does not apply to non-metallic sheathed cable generally. Read a little further and you will come to 300.3(B)(3) which would allow the conductors of a circuit to be in different non-metallic sheathed cables if 300.20(B) is complied with.

I may be the only fan but in resi, I would think about running smurf from the kludge ceiling box to the switch locations. That eliminates a bunch of problems.

When I was in business, I would always run my feed to a 3 way/(4W) switch to the first box, then leave the last box to go to the light fixture. This way it was always easier to trace out problems. I never had to drop down lights to see if I had a feed in there. I could check for incoming feed at the switch. So now with the new code, it would not be an issue.

P.S. when the new code goes into effect, do you think the AHJ will look at each box to make sure that there is a neutral in there?

If it is the "violation of the week" they will. That seems to be the way things go.

The inspectors I have seen will blitz one particular violation (along with the normal look/see) until all of their installers get into line. It is usually right after a seminar where they all talk about it.
I agree it will be something that will add some time to your inspections trying to figure out where are the wires are coming from and going to. In one of those big 4 and 5 gang boxes with multiple circuits feeding it, this might really be a trick. Just because there is a neutral, doesn't mean it is the right neutral.

I use Harold's method for three ways and single pole switches. The main reason I do this is to save a couple of trips up & down a ladder, which is my least favorite tool, and I absolutely hate taking down a light fixture just to troubleshoot connections that could have been avoided by running power to the switch location rather than dropping a switch leg from the fixture box.

As far as neutrals at the switch are concerned, I've seen Howard Homeowner use the equipment ground as a current carrying conductor often enough to think that requiring a neutral at the switch location is a good idea. To the average homeowner, the only difference between a grounded conductor (neutral) and a grounding conductor is the insulation. It'll probably take a few code cycles to work out some of the kinks pointed out by others.

I would say that Code writers are preparing the whole land for Title 24 type energy conservation gadgets which are expected to need a grounded conductor.

Otherwise, the demand seems to be a deliberate attempt at wasting copper, time and other materials.

Tesla, I agree with you.

That's been a sore spot with me for years; if you search this site you'll find I had a thread long ago, asking if the NEC had lost focus.

The question is just where 'practical safeguarding' and 'good design' part ways. Make no bones about it; many of the 'safety' arguments are dependent upon design choices. (For example, compare the different US and UK approaches to power in bathrooms).

The NEC plainly states that it is not a design manual, and explains that a 'safe' installation might not be the most efficient design, or have any provisions for future changes.

I don't want to get off on a tangent; if we want to discuss this in more depth, perhaps a new thread is in order.

The real reason behind this rule is so that UL can correct a mistake they made when they permitted electronic switching type device to use the EGC as the grounded conductor. The standard permits up to 0.5mA of current on the grounding conductor. While this is not enough to cause a serious shock, it is enough to feel and the reaction to this low level shock may result in injury. For example you it may cause you to fall off a ladder or something like that.
I expect that sometime in the not too distant future the UL standard will be changed to prohibit the use of an EGC as a grounded conductor for these devices.

Don:

Thanks! I believe you hit it on the head!

New code is telling us not to dead end 3-way switch by switching and feeding on 1-side and taping w/b traveler,instead just switch on 1-side and feed on the other so white is true neutral