confirm Three Way wiring

Reply

  #1  
Old 08-18-14, 06:29 PM
Member
Thread Starter
Join Date: Nov 2013
Posts: 225
confirm Three Way wiring

I wanted to make sure I wired this 3 way lighting circuit correctly. Everything works as I hoped but I just wanted to confirm....

Feed goes to light fixture then to switch A then to switch B.

At light fixture box, fixture neutral connected to feed neutral. feed hot passes thru the fixture box, the switch A box and is connected to the common screw at switch B. The fixtures hot wire is connected to a switched hot which connects to the common on switch A. Travelers run between switch A and B.

Does that sound correct as I describe it?
 
Sponsored Links
  #2  
Old 08-18-14, 06:33 PM
Tolyn Ironhand's Avatar
Group Moderator
Join Date: Nov 2007
Location: Twin Cities, MN
Posts: 12,284
Yes, unless you are on 2011 or newer code. Then you are required to have a neutral in each switch box.
 
  #3  
Old 08-18-14, 06:35 PM
Member
Thread Starter
Join Date: Nov 2013
Posts: 225
I am on 2008 but I remember reading something about that neutral issue which is partly the reason I asked here. How does that work in my case with the feed at the light first? What is the benefit having a neutral in each switch box in this case?

So in other words, feed at the light first is a code violation now?
 
  #4  
Old 08-18-14, 06:45 PM
Member
Join Date: Jul 2014
Location: usa
Posts: 279
Informational Note: The provision for a (future) grounded
conductor is to complete a circuit path for electronic light-
ing control devices.



if you do not have a white wire you will not be able to use an electronic lighting control device which requires a white wire.

BUT

NEC404.2 Switch Connections.

(A) Three-Way and Four- Way Switches. Three-way and
four-way switches shall be wired so that all switching is
done only in the ungrounded circuit conductor. Where in
metal raceways or metal-armored cables, wiring between
switches and outlets shall be in accordance with 300.20(A).

Exception: Switch loops shall not require a grounded
conductor.
 
  #5  
Old 08-18-14, 06:46 PM
Tolyn Ironhand's Avatar
Group Moderator
Join Date: Nov 2007
Location: Twin Cities, MN
Posts: 12,284
Since you are on 2008 code you are OK. The reason for the change in 2011 is the increasing use of motion/occupancy sensors, dimmers, and other smart switches. Many of them require a neutral wire to function properly.

What happens when there is no neutral available is people will connect the switch neutral to ground, which has the same potential as neutral. This will cause current to flow on the ground wires which is a very bad thing.

You can still feed a light first, it would just take another wire for the neutral. This might involve using a 14/3, 14/4, or 2 x 14/2 cables
 
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
Display Modes