Where are 3-ways required?

[ssandoval]

Does anyone know if there are code stipulations for where 3-ways are required? I have many Mechanical rooms in a new high school that we are trying to get out of warranty, that have doors at both ends but only switches at one entry. I have always assumed that the code required 3-ways under these circumstances but could not find anything. Anyone have any info? Thanks.

 

[haskindm]

Other than at stairways, I don't know of anywhere that the NEC requires 3-ways. That is a design issue, not an NEC issue. In fact, for most rooms there is nothing in the NEC that requires that the switch be located near the door.

 

[George Stolz]

Not even stairways, if you read 210.70 closely.

 

[gndrod]

3-way

3-way

I believe that the NEC does not specify 3-way switch use by installation application. Check local ordinances and the new high school plan specs for 3-way installations as a binding requirement. Ingress safety could be a worthwhile issue for what you described. rbj

 

[cowboyjwc]

Other than at stairways, I don't know of anywhere that the NEC requires 3-ways. That is a design issue, not an NEC issue. In fact, for most rooms there is nothing in the NEC that requires that the switch be located near the door.

Sorry George I have to agree with Haskindm. 210.70(2)(c)

 

[George Stolz]

Sorry George I have to agree with Haskindm. 210.70(2)(c)

I can use two single pole switches if I so desired. It doesn't say a word about being able to extinguish the light from either end of the stairs.

 

[raider1]

Sorry George I have to agree with Haskindm. 210.70(2)(c)

Read that section close as George has pointed out and point out the specific requirement for 3-way switches.

Chris

 

[Dennis Alwon]

I can use two single pole switches if I so desired. It doesn't say a word about being able to extinguish the light from either end of the stairs.

And who would do that? I can see 2 sp switches to a contactor but I can't imagine not installing a 3 way.

I agree the code says what it says----

 

[charlie b]

I can use two single pole switches if I so desired. It doesn't say a word about being able to extinguish the light from either end of the stairs.

I'm with George on this one (a rare, but not impossible event ). I'll add that it doesn't even say you have to be controlling the same light. I can have two lights over a staircase, with a single pole switch upstairs controlling one of them, and another single pole switch controlling the other. Not convenient, but not a violation either.

 

[Dennis Alwon]

I'm with George on this one (a rare, but not impossible event ). I'll add that it doesn't even say you have to be controlling the same light. I can have two lights over a staircase, with a single pole switch upstairs controlling one of them, and another single pole switch controlling the other. Not convenient, but not a violation either.

I am not sure I agree with that second part. I thought that also but it says there shall be a switch at each level controlling the lighting outlet(S).

I should know better than to argue with Charlie but....

 

[charlie b]

I should know better than to argue with Charlie but....

Feel free, anytime. I am as human as the next superhero. :wink: :grin:

I am not sure I agree with that second part. I thought that also but it says there shall be a switch at each level controlling the lighting outlet(S).

It?s a good point. But after looking closely one more time, I am sticking with my answer. I don?t read this sentence as requiring each switch to control any and all lighting outlets in the area. First, it talks about a collection of switches: one on each floor level, and one on each landing that has an entryway. Then it says that that collection of switches is there to control the lighting outlets. What this means, to me at least, is that as long as somewhere in that group of switches I can turn on and off any lighting outlet in the area, I have met the minimum requirements.

Also, please observe the impact of the exception, on the question of three-way switches. If I were to put a switch at each level, and have the switches connect to a remote lighting controller, I can set it up to work in the same fashion as a three-way system would work, but none of the individual switches would be of the three-way construction.

 

[George Stolz]

I am not sure I agree with that second part. I thought that also but it says there shall be a switch at each level controlling the lighting outlet(S).

I should know better than to argue with Charlie but....

Nah, I argue with Charlie all the time, it's no big deal. Only once did he buy a plane ticket to come personally punch me in the nose - but in that instance, I did have it coming.

(2) Additional Locations. Additional lighting outlets shall
be installed in accordance with (A)(2)(a), (A)(2)(b), and
(A)(2)(c).
(a) At least one wall switch-controlled lighting outlet
shall be installed in hallways, stairways, attached garages,
and detached garages with electric power.

So we need a lighting outlet, and a switch controlling it.

(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 entryway, to
control the lighting outlet(s) where the stairway between
floor levels has six risers or more.

Each level must have a switch to control the required lighting outlet.

What is your definition of control? I think that defines the question.

If I push a bowling ball off the stairs, didn't I direct it to fall by my own control? If I don't care to get it back without walking down the stairs, then I don't need to tie a string to it...

 

[wbalsam1]

210.70(A)(2)(c) indicates that if all the lighting outlets are on the same circuit (one comes on, they all come on) this would dictate a three-way or four-way(s) depending of course on elevation change. "There shall be a wall switch at each floor level...to control the lighting outlet(s)....."

However, if the wall switch controls a lighting outlet at one floor level only, it need only be controlled by a single pole switch. Each other level could be configured the same. (not a good design, perhaps, but code compliant.

 

[cowboyjwc]

You know I started to say you could have two lights and one switch control each one, (I'm not sure how you would control one light with two SP switches, but thats ok), but I thought nope that will just start a bunch of opinions and George will just close the tread.:grin:

 

[George Stolz]

You know I started to say you could have two lights and one switch control each one, (I'm not sure how you would control one light with two SP switches, but thats ok), but I thought nope that will just start a bunch of opinions and George will just close the tread.:grin:

I changed my signature just for you, John.

Simple - tie the light(s) to each of the single pole switches. Do I have to spell everything out?

 

[charlie b]

Simple - tie the light(s) to each of the single pole switches. Do I have to spell everything out?

You know, I think that would also be legal. In order for the lights to work, you may have to have both single pole switches in the up position (all other combinations have the lights out). So when you want to turn on the lights, you may have to hit one switch, climb the stairs, and hit the other switch. Not at all a good situation, and certainly not the intent of the code writers. But the words, as written, would not forbid it.

 

[charlie b]

Nah, I argue with Charlie all the time, it's no big deal. Only once did he buy a plane ticket to come personally punch me in the nose - but in that instance, I did have it coming.

I live in fear of the day he realizes that I used his charge card to buy the ticket. :grin:

 

[cowboyjwc]

I changed my signature just for you, John.

Simple - tie the light(s) to each of the single pole switches. Do I have to spell everything out?

Now let's play inspector for a minute. I know what you think it says, but I'm going to tell you what it means (90.4). See three way at top and bottom.:grin: :grin:

 

[Dennis Alwon]

Now let's play inspector for a minute. I know what you think it says, but I'm going to tell you what it means (90.4). See three way at top and bottom.:grin: :grin:

I have no doubt that most inspectors feel exactly as you do. SP switch will not fly anywhere here.