3 way switches

[stickboy1375]

Here is a good one that I like to do for basement stairs,(works well with a fixture at the top and bottom of stairs) 3 way at the bottom of stairs has feed, I will run 3 conductor from bottom of stairs to bottom fixture, then pull a 4 wire out of the fixture to the 3 way at the top of the stairs, then I can pull another load out of the box at the top of the stairs...

 

[BackInTheHabit]

Why? if the feed isnt at either 3way it pretty much solves the mystery...

The mystery is why you would feed a 3way from a light box. It may be somewhat easier on RI but it can create such havoc. Think in the long term.

Why would you want to take down a light fixture (luminaire - sorry:grin: ) to troubleshoot a circuit? It is much easier to pull a switch and test the circuit than it is to take down a luminaire.

 

[stickboy1375]

Why would you want to take down a light fixture (luminaire - sorry:grin: ) to troubleshoot a circuit? It is much easier to pull a switch and test the circuit than it is to take down a luminaire.

Why would I care?

 

[BackInTheHabit]

Why would I care?

Nice attitude.

 

[iwire]

The mystery is why you would feed a 3way from a light box. It may be somewhat easier on RI but it can create such havoc. Think in the long term.

I have no idea what havoc you see. What has the long term have to do with it. :-?

I try to wire for the conditions and not get stuck on any one method. :smile:

 

[stickboy1375]

Nice attitude.

Its not that, its why would it bother me taking a fixture down?

 

[Dennis Alwon]

Its not that, its why would it bother me taking a fixture down?

It could be a pain in the butt over the stairs. I avoid splices in fixtures other than for the light--- to each his own.

 

[BackInTheHabit]

I have no idea what havoc you see. What has the long term have to do with it. :-?

I try to wire for the conditions and not get stuck on any one method. :smile:

The havoc I see is multiple wires in a light box and backfed switches. Having to pull down a ceiling fan a HO put up to troubleshoot the junctions in a light box to locate a loose neutral.

When speaking of long term I'm referring to others that come behind you.

I agree there are times when it has to be done like when you can't drill through a pre-fab laminated beam. It is not a rule that I can always follow but I do when I can.

 

[stickboy1375]

When speaking of long term I'm referring to others that come behind you.

I've yet to come to a job where ANY thought was involved, i'm not about to start worrying about the next guy...:roll:

I dont get paid to think anyways...

 

[POWER_PIG]

I 'dead end' three ways when I it suits the job.

If the feed is at the fixture all you need is a two wire cable from the fixture to the first three way then a three wire cable to all the other four ways / three way you want.

That is a legal way, it complies with 300.3(B), however there are ways to do it and violate 300.3(B).

Bob, can you elaborate on this method? I'm having a hard time getting a visual. Your saying if you have a feed at the fixture you can run 2 wire to the first 3way and then 3 wire in between all the 4way/3ways and just dead end at the last 3way? What do you do about the common for the the 1st switch? Oh wait,,,,your saying run the 3 wire from the fixture box to rest of the devices and dead end them? Wow, Im embarrased not knowing this method that everyone else feels at ease with.
Im off to the white board.

 

[stickboy1375]

Bob, can you elaborate on this method? I'm having a hard time getting a visual. Your saying if you have a feed at the fixture you can run 2 wire to the first 3way and then 3 wire in between all the 4way/3ways and just dead end at the last 3way? What do you do about the common for the the 1st switch? Oh wait,,,,your saying run the 3 wire from the fixture box to rest of the devices and dead end them? Wow, Im embarrased not knowing this method that everyone else feels at ease with.
Im off to the white board.

draw it on paper, this is alot simpler than people make it... if your feed is at the light then you drop a 3 conductor from the light to each switch.

 

[BackInTheHabit]

Its not that, its why would it bother me taking a fixture down?

16' ceiling - Not being afraid of heights.
Only having an 8' ladder with you. - Not a good day.
Knowing wires aren't backfed - Priceless:grin:

 

[EBFD6]

This thread is kinda making me feel bad about getting mad at apprentices for screwing things like this up. Seems to be an awful lot of different ways to accomplish the same thing, and even guys w/ some experience are confused. I never really put much thought into things like this but the more I read I think I might owe an apology to an apprentice or two.

Anyone else thinking the same thing?

 

[stickboy1375]

16' ceiling - Not being afraid of heights.
Only having an 8' ladder with you. - Not a good day.
Knowing wires aren't backfed - Priceless:grin:

I'm still not following your method of madness, someone could still have a bad connection at the fixture... who cares if you splice the 3way in the box or not...

 

[POWER_PIG]

draw it on paper, this is alot simpler than people make it... if your feed is at the light then you drop a 3 conductor from the light to each switch.

Oh OK,,,,,I must have mis-read Iwires post, I thought he said drop a 2 wire to the first switch, I do understand the mechanics behind dead end 3 ways, just not with a 2 wire to the first 3 way. I will go back to re-read his post.
Thanks,
Pig

 

[BackInTheHabit]

I'm still not following your method of madness, someone could still have a bad connection at the fixture... who cares if you splice the 3way in the box or not...

In my experience this is because of too many wires in a light box. With just a switchleg in the lightbox, not much other than the light and the switchleg can go wrong.

Let's say a HO wants you to install a ceiling fan on a first floor room. There is an existing light box in the ceiling. The HO has purchased a ceilng fan that must be well supported. You need to put in a new fan box to support the ceiling fan.

Would you rather have this:
When you take down the light fixture there are 4 - 14/3's and 2 - 14/2's. There is no way to make a junction in the fan or fan box and there isn't enough slack in the wire. The existing box won't support a ceiling fan. The ceiling fan can't be installed because of too many wires and not being able to make a compliant installation.

Or would you rather have this:
When you take down the light fixture you find a single 14/2 feeding the light. You install a new fan box and ceiling fan and walk away from a satisifed customer.

 

[stickboy1375]

Or would you rather have this:
When you take down the light fixture you find a single 14/2 feeding the light. You install a new fan box and ceiling fan and walk away from a satisifed customer.

Actually I would rather have a feed and a switch at the fan, but thats just me... :grin:

 

[wirebender]

Oh OK,,,,,I must have mis-read Iwires post, I thought he said drop a 2 wire to the first switch, I do understand the mechanics behind dead end 3 ways, just not with a 2 wire to the first 3 way. I will go back to re-read his post.
Thanks,
Pig

He did. Run a 2 wire to the first switch. White will carry the hot. Black will be the switch leg returning. Land one on the common of the first 3-way. The other will tie to whatever wire you have coming from the common of the other 3-way.

 

[stickboy1375]

In my experience this is because of too many wires in a light box. With just a switchleg in the lightbox, not much other than the light and the switchleg can go wrong.

Let's say a HO wants you to install a ceiling fan on a first floor room. There is an existing light box in the ceiling. The HO has purchased a ceilng fan that must be well supported. You need to put in a new fan box to support the ceiling fan.

Would you rather have this:
When you take down the light fixture there are 4 - 14/3's and 2 - 14/2's. There is no way to make a junction in the fan or fan box and there isn't enough slack in the wire. The existing box won't support a ceiling fan. The ceiling fan can't be installed because of too many wires and not being able to make a compliant installation.

Or would you rather have this:
When you take down the light fixture you find a single 14/2 feeding the light. You install a new fan box and ceiling fan and walk away from a satisifed customer.

I dont like what if's. its a waste of time to even think about "what if"

 

[stickboy1375]

He did. Run a 2 wire to the first switch. White will carry the hot. Black will be the switch leg returning. Land one on the common of the first 3-way. The other will tie to whatever wire you have coming from the common of the other 3-way.

Opps, my mistake, you can wire them that way also... :grin: