the use of two wire romex in three-way switch loop
- Thread starter sparky902
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Re: the use of two wire romex in three-way switch loop
sparky, roger--
You can't use 12-2 or 14-2 because you have to have a return conductor (neutral) that runs with the supply conductors. And you can't use the equipment grounding conductor (bare copper) as a current-carrying conductor.
Or roger, do you set your 3-way circuits up differently than I do?
Cliff
sparky, roger--
You can't use 12-2 or 14-2 because you have to have a return conductor (neutral) that runs with the supply conductors. And you can't use the equipment grounding conductor (bare copper) as a current-carrying conductor.
Or roger, do you set your 3-way circuits up differently than I do?
Cliff
- Location
- Illinois
- Occupation
- retired electrician
Re: the use of two wire romex in three-way switch loop
cliff,
300.3(B)(3) permits the use of 2 wire NM in 3-way circuits.
Don
cliff,
300.3(B)(3) permits the use of 2 wire NM in 3-way circuits.
Don
Re: the use of two wire romex in three-way switch loop
Cliff, the EGC (bare copper) would remain just that.
I don't understand what you mean by,
Remember, we are talking about travelers, or one hot wire, in a non inductive wiring method, and unless these single conductors are entering a metal box, this would eliminate 300.20 as covered in 300.3
Roger
Cliff, the EGC (bare copper) would remain just that.
I don't understand what you mean by,
this is not in the NEC as far as NM.
Remember, we are talking about travelers, or one hot wire, in a non inductive wiring method, and unless these single conductors are entering a metal box, this would eliminate 300.20 as covered in 300.3
Roger
russellroberts
Senior Member
- Location
- Georgia
Re: the use of two wire romex in three-way switch loop
Roger,I think he's talking about feeding the 3-way on one end,carrying the neutral through the 3 wire to the other end, and taking the switch leg up to the lite from there.
I think.
russell
Roger,I think he's talking about feeding the 3-way on one end,carrying the neutral through the 3 wire to the other end, and taking the switch leg up to the lite from there.
I think.
russell
A
a.wayne3@verizon.net
Guest
Re: the use of two wire romex in three-way switch loop
I used 2 wire travelers many times over the years,
In most cases a standard 3 way fed from one end and switched from the other,or a dead ended 3 way uses 3 wires.There are some cases in which it is not necessary to use the 3 wire nm.Where there are multiple switches on a circuit(multi gang) and the neutral from this circuit is already there
Then you can use a 2 wire traveler in lieu of the more expensive 3 wire.Or when there is a 3 way 4 way 3 way switching system and at the 4 way there is a single pole switch then I have run 2 2 wires one as a feed (hot /neutral) and one as travellers.I have seen guys run 2 wire travelers to another circuit and use that neutral IMHO
as long as you are carefull that you don`t share a neutral from another circuit there is nothing wrong with this
I used 2 wire travelers many times over the years,
In most cases a standard 3 way fed from one end and switched from the other,or a dead ended 3 way uses 3 wires.There are some cases in which it is not necessary to use the 3 wire nm.Where there are multiple switches on a circuit(multi gang) and the neutral from this circuit is already there
Then you can use a 2 wire traveler in lieu of the more expensive 3 wire.Or when there is a 3 way 4 way 3 way switching system and at the 4 way there is a single pole switch then I have run 2 2 wires one as a feed (hot /neutral) and one as travellers.I have seen guys run 2 wire travelers to another circuit and use that neutral
IMHOas long as you are carefull that you don`t share a neutral from another circuit there is nothing wrong with this
Re: the use of two wire romex in three-way switch loop
Thank-you gentlemen for answering my question so fast.
I did some more investigating on the subject myself, and found some information in Mike Holt's, "1999 NEC Illustrated Changes" book, page 14 figures 2-2 and 2-3. Figure 2-3 states:
"white conductors must be re-identified when used as travelers between 3 and 4-way switches".
Thank-you
Thank-you gentlemen for answering my question so fast.
I did some more investigating on the subject myself, and found some information in Mike Holt's, "1999 NEC Illustrated Changes" book, page 14 figures 2-2 and 2-3. Figure 2-3 states:
"white conductors must be re-identified when used as travelers between 3 and 4-way switches".
Thank-you
jxofaltrds
Inspector Mike®
- Location
- Mike P. Columbus Ohio
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- ESI, PI, RBO
Re: the use of two wire romex in three-way switch loop
Don
Please explain 300.3(B)(3) to me. I do not see how this is allowed. How are you going to comply with 300.20?
I think that 300.3(B) prohibits 12-2 or 14-2. The grounded conductor is not in the same raceway.
What about EMF?
Mike P.
Don
Please explain 300.3(B)(3) to me. I do not see how this is allowed. How are you going to comply with 300.20?
I think that 300.3(B) prohibits 12-2 or 14-2. The grounded conductor is not in the same raceway.
What about EMF?
Mike P.
- Location
- Illinois
- Occupation
- retired electrician
Re: the use of two wire romex in three-way switch loop
Mike,
Using NM cable there is no requirement that all of the conductors of the circuit be in the same raceway. 300.20 can be complied with by using NM connectors listed for more than one conductor or by using nonmetallic boxes. Yes, these installations will create more EMF, but that is not a code issue at this time.
Don
Mike,
Using NM cable there is no requirement that all of the conductors of the circuit be in the same raceway. 300.20 can be complied with by using NM connectors listed for more than one conductor or by using nonmetallic boxes. Yes, these installations will create more EMF, but that is not a code issue at this time.
Don
- Location
- Illinois
- Occupation
- retired electrician
Re: the use of two wire romex in three-way switch loop
Ron,
Read part (3) of the same section in the '99 and '02 codes. The answers given on this board are normally based on the 2002 code unless the original post specifies an earlier code.
Don
Ron,
Read part (3) of the same section in the '99 and '02 codes. The answers given on this board are normally based on the 2002 code unless the original post specifies an earlier code.
Don
hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
Re: the use of two wire romex in three-way switch loop
You do not have to run a grounded conductor with a switch loop as per.
404.2
Exception: Switch loops shall not require a grounded conductor.
You do not have to run a grounded conductor with a switch loop as per.
404.2
Exception: Switch loops shall not require a grounded conductor.
karl riley
Senior Member
Re: the use of two wire romex in three-way switch loop
Yes, the switch loop is different from the travelers.
But those who cite the change in 300-3(b) in 1999 as allowing the use of 2-wire travelers, you are correct as to Code unless one circuit supplies the hot and another circuit supplies the neutral. There may be no metallic enclosures until the circuits get back to the panel. Then, according to 300-20 you would have to cut a slot in the box between where the two circuits enter. Obviously not allowed, so that set-up would not work.
But if you use parts of only one circuit to feed the hot on one end and neutral on the other, you are satisfying the Code change, as long as no metal is traversed.
But do you think that the sometimes huge magnetic field that is set up in the whole area served by the three-way lights is something an electrician wants to set up? To save a couple of bucks? I can guarantee you that in office space this field would make the use of computers in the area probably impossible, due to the strain on the users' eyes due to the jitter. So why say it's OK, even though this Code change lets you get away with it?
Karl
Yes, the switch loop is different from the travelers.
But those who cite the change in 300-3(b) in 1999 as allowing the use of 2-wire travelers, you are correct as to Code unless one circuit supplies the hot and another circuit supplies the neutral. There may be no metallic enclosures until the circuits get back to the panel. Then, according to 300-20 you would have to cut a slot in the box between where the two circuits enter. Obviously not allowed, so that set-up would not work.
But if you use parts of only one circuit to feed the hot on one end and neutral on the other, you are satisfying the Code change, as long as no metal is traversed.
But do you think that the sometimes huge magnetic field that is set up in the whole area served by the three-way lights is something an electrician wants to set up? To save a couple of bucks? I can guarantee you that in office space this field would make the use of computers in the area probably impossible, due to the strain on the users' eyes due to the jitter. So why say it's OK, even though this Code change lets you get away with it?
Karl
jxofaltrds
Inspector Mike®
- Location
- Mike P. Columbus Ohio
- Occupation
- ESI, PI, RBO
Re: the use of two wire romex in three-way switch loop
In the above question using the 2 wire for travelers:
You are required to combine all grounds in each three-way switch box.
This creates paralleled egc's.
Is this not a violation of 310.4?
Mike P.
In the above question using the 2 wire for travelers:
You are required to combine all grounds in each three-way switch box.
This creates paralleled egc's.
Is this not a violation of 310.4?
Mike P.
jxofaltrds
Inspector Mike®
- Location
- Mike P. Columbus Ohio
- Occupation
- ESI, PI, RBO
Re: the use of two wire romex in three-way switch loop
After reading my post it does not make sense. I will leave it maybe someone can spin-off of it.
Mike P.
After reading my post it does not make sense. I will leave it maybe someone can spin-off of it.
Mike P.
karl riley
Senior Member
Re: the use of two wire romex in three-way switch loop
Mike, I just checked: 310-4 refers to phase, neutral or grounded conductors, not to equipment grounding conductors.
Anyone have a comment on my previous post? I need feedback. I have no idea why 300-3(b) was changed in 1999. It was a thoroughly sound rule: keep all the conductors together. The NM exceptions take us back to knob and tube runs. What was the purpose of the change? Anyone know?
Karl R.
Mike, I just checked: 310-4 refers to phase, neutral or grounded conductors, not to equipment grounding conductors.
Anyone have a comment on my previous post? I need feedback. I have no idea why 300-3(b) was changed in 1999. It was a thoroughly sound rule: keep all the conductors together. The NM exceptions take us back to knob and tube runs. What was the purpose of the change? Anyone know?
Karl R.
Re: the use of two wire romex in three-way switch loop
Hello Karl, I see and have thought about the EMF angle before in this wiring method, but in my case it has been residential and no more than a hall way light or two.
In the commercial aspect, I could see heavy loaded flourescent circuits causing a substantial increase in the problem.
With the NEC sell out to the metalic industry disallowing NM above suspended ceilings in commercial settings, I can also see this method being more of a convenience, and in turn, adding to the problem again.
Now, I must ask, where was this method prohibited before the 99 code cycle. The wording of 300.3 even in the 96 code, simply intended that all conductors of one circuit be in a common raceway or cable if all conductors were needed. If all were not needed, they were never required to be installed in a raceway or cable just to waste resources.
Roger
[ July 02, 2003, 09:53 PM: Message edited by: roger ]
Hello Karl, I see and have thought about the EMF angle before in this wiring method, but in my case it has been residential and no more than a hall way light or two.
In the commercial aspect, I could see heavy loaded flourescent circuits causing a substantial increase in the problem.
With the NEC sell out to the metalic industry disallowing NM above suspended ceilings in commercial settings, I can also see this method being more of a convenience, and in turn, adding to the problem again.
Now, I must ask, where was this method prohibited before the 99 code cycle. The wording of 300.3 even in the 96 code, simply intended that all conductors of one circuit be in a common raceway or cable if all conductors were needed. If all were not needed, they were never required to be installed in a raceway or cable just to waste resources.
Roger
[ July 02, 2003, 09:53 PM: Message edited by: roger ]
karl riley
Senior Member
Re: the use of two wire romex in three-way switch loop
Roger, it's true that 300-3(b) has to be observed in metal conduits, so in the case of large loads large net currents will not be created if Code is observed.
About pre-1999, I just checked my '93 NEC and I see no exceptions about "not needed" conductors of a circuit. Where did you get that from? It just says all conductors of a circuit including EGCs. ???
When using two-conductor travelers, part of the circuit will be missing the hot and part of it will miss neutral (currents).
I am curious why NM was exempted in 1999, since all recent revisions have reduced EMF sources (eliminating currents on gas pipes, eliminating neutral on dryer cases and whatever they are touching, eliminating neutral on pipes supplying an outbuilding). These were all progressive steps in keeping magnetic field levels to insignificant.
Karl
Roger, it's true that 300-3(b) has to be observed in metal conduits, so in the case of large loads large net currents will not be created if Code is observed.
About pre-1999, I just checked my '93 NEC and I see no exceptions about "not needed" conductors of a circuit. Where did you get that from? It just says all conductors of a circuit including EGCs. ???
When using two-conductor travelers, part of the circuit will be missing the hot and part of it will miss neutral (currents).
I am curious why NM was exempted in 1999, since all recent revisions have reduced EMF sources (eliminating currents on gas pipes, eliminating neutral on dryer cases and whatever they are touching, eliminating neutral on pipes supplying an outbuilding). These were all progressive steps in keeping magnetic field levels to insignificant.
Karl
Re: the use of two wire romex in three-way switch loop
Karl,
Conductors of the Same Circuit. All conductors of the same circuit and, where used, the grounded conductor and all equipment grounding conductors shall be contained within the same raceway,cable tray, trench, cable, or cord.
the wording of the 99 is as follows; (additional or changed wording in italics)
Conductors of the Same Circuit. All conductors of the same circuit and, where used, the grounded conductor and all equipment grounding conductors shall be contained within the same raceway,auxiliary gutter, cable tray, trench, cable, or cord, unless otherwise permitted in accordance with (1) through (4)
the wording of the 02 is as follows; (additional or changed wording in italics)
Conductors of the Same Circuit. All conductors of the same circuit and, where used, the grounded conductor and all equipment grounding conductors and bonding conductors shall be contained within the same raceway, auxiliary gutter, cable tray, trench, cable, or cord, unless otherwise permitted in accordance with (1) through (4).
This is the way I interpret these paragraphs.
Note: This is my opinion, which is no more than just that. (see the Handbook thread concerning opinions )
The conductors of a given circuit can not be intalled in more than one raceway, auxiliary gutter, cable tray, trench, cable, or cord, unless otherwise permitted in accordance with (1) through (4).
I don't see the wording requiring unecessary conductors in a raceway, auxiliary gutter, cable tray, trench, cable, or cord.
Now,
Roger
Karl,
I don't have my 93 handy, but the wording in the 96 is as follows;
Conductors of the Same Circuit. All conductors of the same circuit and, where used, the grounded conductor and all equipment grounding conductors shall be contained within the same raceway,cable tray, trench, cable, or cord.
the wording of the 99 is as follows; (additional or changed wording in italics)
Conductors of the Same Circuit. All conductors of the same circuit and, where used, the grounded conductor and all equipment grounding conductors shall be contained within the same raceway,auxiliary gutter, cable tray, trench, cable, or cord, unless otherwise permitted in accordance with (1) through (4)
the wording of the 02 is as follows; (additional or changed wording in italics)
Conductors of the Same Circuit. All conductors of the same circuit and, where used, the grounded conductor and all equipment grounding conductors and bonding conductors shall be contained within the same raceway, auxiliary gutter, cable tray, trench, cable, or cord, unless otherwise permitted in accordance with (1) through (4).
This is the way I interpret these paragraphs.
Note: This is my opinion, which is no more than just that. (see the Handbook thread concerning opinions
)The conductors of a given circuit can not be intalled in more than one raceway, auxiliary gutter, cable tray, trench, cable, or cord, unless otherwise permitted in accordance with (1) through (4).
I don't see the wording requiring unecessary conductors in a raceway, auxiliary gutter, cable tray, trench, cable, or cord.
Now,
another common wiring method is a two wire switch drop, this does nullify the MF, but this is still missing atleast one or more conductors associated with a given circuit, and even if we add the grounded conductor, with out designing this conductor to return or pass through the switch box to another point of connection as a current carrying conductor, we haven't achieved anything except wasting resources.
Roger
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