3 Way Switching

Status
Not open for further replies.
K

K_Buz

Member
Location
Southeastern Wisconsin
Is it legal to run 2 2wire NM's to wire between 2 3 way switches?

On one hand, in 404.2 (A) doesn't specifically prohibit this.
On the other hand, 300.3 (B) states that all conductors of a circuit must be contained in the same cable.
On the other hand, wiring between two 3 way switches isn't exactly a circuit.

Now, let me explain. I would never do this in a rough in situation, but a question was posed in a retrofit application that this would be really convenient to do.
 
well, these days (2011 code) we need the grounded conductor at each switch
sometimes we can run a 3wire traveler sending the neutral with the switch leg on the end of it

it says we need a "neutral" at each switch ... not a constant feed
 
The specific situation was this...

Home was recently built with 2 single pole switches at the top of the basement stairs with the switch legs running to the basement for future lighting. They wanted to know if they could use the 2 2 wire switch legs and install 1 3way at the top and the other 3way at the bottom. It wasn't an easy fish up to the 2 gang due to the stair framing (not impossible, just difficult for the homeowner).
 
K_Buz said:
The specific situation was this...

Home was recently built with 2 single pole switches at the top of the basement stairs with the switch legs running to the basement for future lighting. They wanted to know if they could use the 2 2 wire switch legs and install 1 3way at the top and the other 3way at the bottom. It wasn't an easy fish up to the 2 gang due to the stair framing (not impossible, just difficult for the homeowner).
Click to expand...

sounds like it would work IMO
isn't there something in the code stating that stairways with more than X number of steps are to be switched from both top an bottom of stairs? (6 i believe)
 
Gac66610 said:
sounds like it would work IMO
isn't there something in the code stating that stairways with more than X number of steps are to be switched from both top an bottom of stairs? (6 i believe)
Click to expand...

210.70 Lighting Outlets Required.
Lighting outlets shall be installed where specified in 210.70(A), (B), and (C).
(A) Dwelling Units. In dwelling units, lighting outlets shall be installed in accordance with 210.70(A)(1), (2), and (3).
(2) Additional Locations. Additional lighting outlets shall be installed in accordance with (a), (b), and (c).
(a) At least one wall switch-controlled lighting outlet shall be installed in hallways, stairways, attached garages, and detached garages with electric power.
(c) Where one or more lighting outlet(s) are installed for interior stairways, there shall be a wall switch at each floor level, and landing level that includes an entry way, to control the lighting outlet(s) where the stairway between floor levels has six risers or more.

....those should have already been wired as three way switches when house was built.
 
I don't know when that code came into play, but in the mid 80's that wasn't code. Since I have only wired one complete house in my 14 years, I haven't had to deal with it, but I have had to add hundreds of 3 ways at the bottom of stairs when they remodeled the basement.

I should add, there may have been a state code amending that, but I don't have the state codes for years past in front of me.
 
K_Buz said:
I don't know when that code came into play, but in the mid 80's that wasn't code. Since I have only wired one complete house in my 14 years, I haven't had to deal with it, but I have had to add hundreds of 3 ways at the bottom of stairs when they remodeled the basement.

I should add, there may have been a state code amending that, but I don't have the state codes for years past in front of me.
Click to expand...

"Home was recently built with 2 single pole switches at the top of the basement stairs with the switch legs running to the basement for future lighting." -K_Buz

....your confusing me......
 
K_Buz said:
I don't know when that code came into play, but in the mid 80's that wasn't code. Since I have only wired one complete house in my 14 years, I haven't had to deal with it, but I have had to add hundreds of 3 ways at the bottom of stairs when they remodeled the basement.

I should add, there may have been a state code amending that, but I don't have the state codes for years past in front of me.
Click to expand...

I keep forgetting different areas, and amendments
here in my base city its adopted without amending any thing
i'm not real sure when that was added to the code

I dont see any reason that the 2 switch legs can't be reworked for the 3ways:)
 
The NEC does not require a 3 way switch. It requires a switch at each level. That can be 2 sp switches controlling 2 separate lights.
 
Dennis Alwon said:
It is compliant with NM cable and if they are close together it will cancel any emf's. But why do that.
Click to expand...

I disgree with you on this, as the previous post stated all conductors of a circuit must be run together. In NM you can create EMF by using 2 wire and not 3 wire NM. I'm of the school of thought that you are not allowed to run 2 wire on a 3 or 4 way switch.

300.3(B)
 
300.3(B)(3) Nonferrous Wiring Methods. Conductors in wiring methods with a nonmetallic or other nonmagnetic sheath , where run in different raceways, auxiliary gutters, cable trays, trenches, cables, or cords, shall comply with the provisions of 300.20(B).

300.20(B) would not apply.

300.20(B) Individual Conductors. Where a single conductor ..........
 
acrwc10 said:
I disgree with you on this, as the previous post stated all conductors of a circuit must be run together. In NM you can create EMF by using 2 wire and not 3 wire NM. I'm of the school of thought that you are not allowed to run 2 wire on a 3 or 4 way switch.

300.3(B)
Click to expand...

Then why not be concerned by EMF in a switch loop for a single pole switch?
 
neutral at switch?

neutral at switch?

Being behind the times here in Connecticut we are still on the 2005 code. (thankful for that with the changes I've seen) I have not heard of this one at all. You need to run the neutral through every switch box? Sounds like a real chore. Like on a 3-way new install you can't feed one end and go to the light from the other?
 
GerryB said:
Being behind the times here in Connecticut we are still on the 2005 code. (thankful for that with the changes I've seen) I have not heard of this one at all. You need to run the neutral through every switch box? Sounds like a real chore. Like on a 3-way new install you can't feed one end and go to the light from the other?
Click to expand...
PHP:


There's an exception to that rule if you have access below or above. Such as a crawl space or attic. Then the neutral is not required.
It's my opinion this was made code by lobbyist that sell smart switches , etc... that require a neutral.
 
acrwc10 said:
I disgree with you on this, as the previous post stated all conductors of a circuit must be run together. In NM you can create EMF by using 2 wire and not 3 wire NM. I'm of the school of thought that you are not allowed to run 2 wire on a 3 or 4 way switch.

300.3(B)
Click to expand...

300.3 (B) 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, ..... cable ....

IMO nothing wrong with 2 wire travelers

waiting to see if my head will roll ;)
 
Gac66610 said:
300.3 (B) 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, ..... cable ....

IMO nothing wrong with 2 wire travelers

waiting to see if my head will roll ;)
Click to expand...

Me too, I used to use two wire for travelers. How are you running the switchleg and neutral? If your feeding it on one end and switching it on the other that means you have a single lead somewhere else. (to and from the light)
 
Status
Not open for further replies.
Top