Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > Electrical

CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!

Reply
 
Thread Tools Search this Thread Display Modes
Old 02-19-2008, 10:01 AM   #1
Member
 
Join Date: Feb 2008
Location: Ottawa Ontario Canada
Posts: 199
Share |
Default

Power to Switch First


I found this forum while searching for info on pot light install.
Saw response to someone by Stubbie on this subject. Could someone comment on the advantages/disadvantages of power to switch first?

In a remodel, I am adding 2 small pot lights to a mid circuit plug. The pot lights (50Watts) have thermal protection and very small box on top. It says it can take max. 2 12AWG IN and 2 12AWG Out. In my view you'd be hard pressed to put 2 #14 IN with wire nuts, so was looking at power to switch first.

Comments please.

orange

orange is offline   Reply With Quote
Old 02-19-2008, 11:06 AM   #2
UAW SKILLED TRADES
 
Stubbie's Avatar
 
Join Date: Jan 2007
Location: Kansas
Posts: 4,876
Default

Power to Switch First


No better than the source to answer. I like power to a switch first for both 3 ways and single poles. This gets a neutral in that box vs. no neutral like a switch loop with power to the light fixture first. Many more options available down the round if changes are made.
As far as one being better than the other they both work and nothing wrong going either way. If only powering one light hitting the switch first will reduce the number of wires in wirenuts at the light fixture. And yes the manufacturers don't give you much room in some of the wiring enclosures. One cable in and one cable out is to allow for connecting to another light and switch loops to a single light.

Stubbie is offline   Reply With Quote
Old 02-19-2008, 11:12 AM   #3
waiting for spring
 
arichard21's Avatar
 
Join Date: Oct 2007
Location: Northern NY
Posts: 171
Default

Power to Switch First


Quick question:

Do they make cables specificly for things like switch loops containing 2 black wires, as opposed to 1 BK 1 WH and coloring the white to identify it as HOT?
arichard21 is offline   Reply With Quote
Old 02-19-2008, 11:37 AM   #4
UAW SKILLED TRADES
 
Stubbie's Avatar
 
Join Date: Jan 2007
Location: Kansas
Posts: 4,876
Default

Power to Switch First


I made a reply then deleted I think the best approach here is to ask why do you think it would make a difference?
Stubbie is offline   Reply With Quote
Old 02-19-2008, 11:49 AM   #5
waiting for spring
 
arichard21's Avatar
 
Join Date: Oct 2007
Location: Northern NY
Posts: 171
Default

Power to Switch First


Quote:
Originally Posted by Stubbie View Post
I made a reply then deleted I think the best approach here is to ask why do you think it would make a difference?

Just curiousity, I guess. I can see several instances that they could be used... switch loops, 240 volt applications, etc.

My thinking is that if a homeowner opens up a switch and sees a white wire with electrical tape or marker on it they aren't always going to know that the white wire is hot...
arichard21 is offline   Reply With Quote
Old 02-19-2008, 12:16 PM   #6
UAW SKILLED TRADES
 
Stubbie's Avatar
 
Join Date: Jan 2007
Location: Kansas
Posts: 4,876
Default

Power to Switch First


Ok thats fair enough. First the NEC and the manufacturers didn't design wiring for the homeowner. They did however expect who ever opens a switch box to understand what they would be looking at and how it is supposed to work. If you saw a white wire connected to a switch you know darn sure it is either hot or switched hot or it would not be landed on a switch. If it is marked black I know it is the constant or power hot. I know this because that is the correct convention. On a 3 way switch it can be a switched traveler as can black and red. If a black and red (we are considering nm-b) are landed on a single pole switch one will be switched hot (usually red) and one will be constant power....again by convention. True gounded legs (neutrals) are never switched in a premise wiring method, unless someone has done something real unorthodox.

Last edited by Stubbie; 02-20-2008 at 12:29 AM.
Stubbie is offline   Reply With Quote
Old 02-19-2008, 12:26 PM   #7
Member
 
Join Date: Nov 2007
Location: Nashua, NH, USA
Posts: 6,866
Default

Power to Switch First


Quote:
Originally Posted by arichard21 View Post
Do they make cables specificly for things like switch loops containing 2 black wires, as opposed to 1 BK 1 WH and coloring the white to identify it as HOT?
14-2 Romex type cable with red and black conductors is used in Canada. It's a low volume (manufactured wise) item and therefore costs a lot more per foot. It would not be universally adopted from this point forward unless the NEC were changed to forbid white-black cables in switch loops.
AllanJ is online now   Reply With Quote
Old 02-19-2008, 12:27 PM   #8
waiting for spring
 
arichard21's Avatar
 
Join Date: Oct 2007
Location: Northern NY
Posts: 171
Default

Power to Switch First


Quote:
Originally Posted by Stubbie View Post
Ok thats fair enough. First the NEC and the manufacturers didn't design wiring for the homeowner. They did however expect who ever opens a switch box to understand what they would be looking at and how it is supposed to work. If you saw a white wire connected to a switch you know darn sure it is either hot or switched hot or it would not be landed on a switch. If it is marked black I know it is the constant or power hot. I know this because that is the correct convention. On a 3 way switch it can be a switched traveler as can black and red. The black or red (we are considering nm-b) will be the switched hot on a single pole switch....again by convention. True gounded legs (neutrals) are never switched in a premise wiring method, unless someone has done something real unorthodox.
Makes sense. Thanks.
arichard21 is offline   Reply With Quote
Old 02-19-2008, 02:10 PM   #9
Member
 
Join Date: Feb 2008
Location: Ottawa Ontario Canada
Posts: 199
Default

Power to Switch First


Quote:
Originally Posted by Stubbie View Post
No better than the source to answer. I like power to a switch first for both 3 ways and single poles. This gets a neutral in that box vs. no neutral like a switch loop with power to the light fixture first. Many more options available down the round if changes are made.
As far as one being better than the other they both work and nothing wrong going either way. If only powering one light hitting the switch first will reduce the number of wires in wirenuts at the light fixture. And yes the manufacturers don't give you much room in some of the wiring enclosures. One cable in and one cable out is to allow for connecting to another light and switch loops to a single light.
Thanks for the response. It's what I was thinking(hoping) but it's good to get confirmation from a tradesman.
orange is offline   Reply With Quote
Old 02-19-2008, 02:53 PM   #10
UAW SKILLED TRADES
 
Stubbie's Avatar
 
Join Date: Jan 2007
Location: Kansas
Posts: 4,876
Default

Power to Switch First


It is also very common to run three wire cable from a single light fixture to the switch box. This will allow for replacement if a ceiling fan/light or some other light and motor operated appliance without rewiring. The red wire is just left unused until needed.
Stubbie is offline   Reply With Quote
Old 02-19-2008, 10:35 PM   #11
electrician
 
Join Date: Feb 2008
Posts: 326
Default

Power to Switch First


Just a side note. There have been NEC proposals to require a neutral at all switches for future "smart" devices which will consume power and not just switch it, and for that a neutral is required. The proposals have failed so far, but it is only a matter of time before it will be required.
Silk is offline   Reply With Quote
Old 02-20-2008, 08:07 PM   #12
Member
 
Join Date: Oct 2007
Posts: 2,294
Default

Power to Switch First


Quote:
My thinking is that if a homeowner opens up a switch and sees a white wire with electrical tape or marker on it they aren't always going to know that the white wire is hot...

It's not called a suicide switch for nothin
220/221 is offline   Reply With Quote
Old 02-21-2008, 05:55 AM   #13
When is fishing season?
 
CowboyAndy's Avatar
 
Join Date: Feb 2008
Posts: 613
Default

Power to Switch First


So, what is the general concensus... do the pros prefer to run power to the switch first or run on a switch loop?
__________________
I DON'T OWN MY HOUSE...
MY HOUSE OWNS ME!
CowboyAndy is offline   Reply With Quote
Old 02-21-2008, 08:20 AM   #14
Licensed Pro
 
Join Date: Mar 2007
Location: SC
Posts: 1,535
Default

Power to Switch First


Quote:
Originally Posted by CowboyAndy View Post
So, what is the general concensus... do the pros prefer to run power to the switch first or run on a switch loop?
Switch first. The only exceptions I make are on remodels where going to the light first is more cost effective.
__________________
"Life is hard. Life is harder when you're stupid." John Wayne
HouseHelper is online now   Reply With Quote
Old 02-21-2008, 08:40 AM   #15
Member
 
Join Date: Nov 2007
Location: Nashua, NH, USA
Posts: 6,866
Default

Power to Switch First


Quote:
Originally Posted by Stubbie View Post
It is also very common to run three wire cable from a single light fixture to the switch box. ... The red wire is just left unused until needed.
By the way, if power came to the fixture, would it be proper to leave the white wire unused for the future? Even though the usage first thought of was a second switch for a fan, etc. and the white wire would have to become the unswitched hot at said later date?

AllanJ is online now   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

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


Similar Threads
Thread Thread Starter Forum Replies Last Post
Adding a Switch and jump power Bull-37 Electrical 9 01-10-2008 05:45 PM
Help! Mystery power in complex 3-way! mnyman2003 Electrical 12 12-16-2007 01:10 PM
Wiring a switch, power from outlet Big Bill Electrical 4 09-15-2007 03:59 PM
Basic Switch wiring question; Dimmer to Toggle switch (Pictures included) inspectator Electrical 8 08-07-2007 01:19 AM
Power disconnect switch lmanwarren Electrical 1 03-28-2006 03:17 AM




Top of Page | View New Posts

Copyright © 2003-2014 Escalate Media. All Rights Reserved.