Go Back  DoItYourself.com Community Forums > Electrical, AC & DC. Electronic Equipment and Computers > Electrical - AC & DC
Reload this Page >

Do the neutrals for a light switch need to be in the same box as the switch?

Do the neutrals for a light switch need to be in the same box as the switch?

Reply

  #1  
Old 04-06-09, 12:03 AM
Member
Thread Starter
Join Date: Mar 2008
Location: Sacramento, CA
Posts: 27
Received 0 Votes on 0 Posts
Do the neutrals for a light switch need to be in the same box as the switch?

In the rough sketch below, can I tie the neutrals together in the jbox and run two hots through the conduit to the switch? or do the neutrals need to be in the switch box too? Both 14/2 NM cables will enter the jbox and transition to #14 THHN into the conduit.


 
Sponsored Links
  #2  
Old 04-06-09, 07:42 AM
Member
Join Date: Feb 2006
Location: USA
Posts: 6,572
Received 4 Votes on 4 Posts
Switch Loop

Yes. You will have a switch loop from the switch to the junction box. Connect the neutrals together in the junction box as you suggested. You will need to run a ground from the junction box to the switch to ground the switch.
 
  #3  
Old 04-06-09, 07:52 AM
Member
Join Date: Jan 2009
Location: Northwestern Ontario (Canada)
Posts: 549
Received 1 Vote on 1 Post
Curious if there's a colour 'standard' for thhn in this app

Obviously this conduit is too small for a standard switchloop of normal 14/2.
Im curious, when you use these small THHN wires for a switch loop, do you follow the black/white/green rule (white hot into switch, black switched out, and green is the box ground).. or can you put any old colours you want in the conduit (ie, all blacks) ??
 
  #4  
Old 04-06-09, 08:17 AM
Banned. Rule And/Or Policy Violation
Join Date: Dec 2007
Location: Chicago
Posts: 1,011
Received 0 Votes on 0 Posts
Originally Posted by DaveC72 View Post
Obviously this conduit is too small for a standard switchloop of normal 14/2.
Im curious, when you use these small THHN wires for a switch loop, do you follow the black/white/green rule (white hot into switch, black switched out, and green is the box ground).. or can you put any old colours you want in the conduit (ie, all blacks) ??
When using individual conductors ideally you would use any color, and only a color, allowed for a ungrounded ("hot") conductor in a switch loop (other than as the ground). Some AHJs allow you to permanently re-identify a while conductor used as a ungrounded ("hot") conductor.

On cables with white insulation on the grounded ("neutral") conductor (such NM), NEC 200.7(c)(1) requires it be permanently re-identified around its entire diameter when used as a ungrounded conductor in a switch loop.
 
  #5  
Old 04-06-09, 09:06 AM
Forum Topic Moderator
Join Date: Feb 2005
Location: Near Lansing, Michigan
Posts: 10,944
Received 42 Votes on 40 Posts
Originally Posted by DaveC72 View Post
Im curious, when you use these small THHN wires for a switch loop, do you follow the black/white/green rule
The ground must be green or bare.
If you were installing one, the neutral must be white or gray.
The hots must be any other colors. (black, red, blue, etc)
 
  #6  
Old 04-06-09, 09:14 AM
Member
Join Date: Sep 2000
Location: United States
Posts: 18,497
Received 0 Votes on 0 Posts
The code exception that allows you to use remarked white wires as hot wires applies only to cable assemblies, never to individual conductors. When using individual conductors, you may never remark a white wire as hot.

And just to summarize for the original poster, there is no code that requires you to run a neutral wire to a switch box. In your case, it would be silly to do so.

On the other hand, the existance of the J-box in your diagram is allowed, but very unusual. Except in extraordinary circumstances, nobody would wire it this way.
 
  #7  
Old 04-06-09, 11:59 AM
Member
Thread Starter
Join Date: Mar 2008
Location: Sacramento, CA
Posts: 27
Received 0 Votes on 0 Posts
Originally Posted by John Nelson View Post
On the other hand, the existance of the J-box in your diagram is allowed, but very unusual. Except in extraordinary circumstances, nobody would wire it this way.
I had a feeling the question about the jbox would come up. Like I said, it's only a rough sketch.. So here's some more detail.

Whoever wired this before did it wrong, so I'm correcting it.

Two 14/2 NM cables are in the attic and run into a hole in the side of the house which go into an LB. One comes from the panel, the other goes to some exterior light fixtures. Inside the LB, both 14/2s are stripped of the outer sheath and fed into conduit on the side of the house as individual conductors (2 hots, 2 neutrals, and one ground). Grounds tied together in the LB. There is a switch at the end of this conduit so the lights can be controlled from outside the house. My plan is to install a jbox in front of the LB so I can transition from the NM to THHN/THWN.

Just for my own curiosity, would it be code compliant to make the splices inside the LB? This is 1/2" conduit and I think the cubic inch capacity of the LB is 4.5. Not too good with box fill calculations. Even if it's acceptable, I'll still likely use a jbox just for the sake of not having to cram all of the splices into the LB.
 
  #8  
Old 04-06-09, 12:38 PM
Banned. Rule And/Or Policy Violation
Join Date: Dec 2007
Location: Chicago
Posts: 1,011
Received 0 Votes on 0 Posts
Originally Posted by John Nelson View Post
The code exception that allows you to use remarked white wires as hot wires applies only to cable assemblies, never to individual conductors. When using individual conductors, you may never remark a white wire as hot.
I actually wrote my original post making exactly that point, but then went back and edited it, reason being that I have seen re-identified white individual conductors pulled through conduit for switch loops which passed inspection in Chicago. That's why I noted that particular AHJs may allow such re-identification.

Is it right per the NEC?

I don't think so.

Can you fight City Hall?

Well...

Best thing to do is ask your AHJ.

----

Home Inspection: "A business with illogically high liability, slim profit margins and limited economies of scale. An incredibly diverse, multi-disciplined consulting service, delivered under difficult in-field circumstances, before a hostile audience in an impossibly short time frame, requiring the production of an extraordinarily detailed technical report, almost instantly, without benefit of research facilities or resources." - Alan Carson
 
  #9  
Old 04-06-09, 01:02 PM
Forum Topic Moderator
Join Date: Feb 2005
Location: Near Lansing, Michigan
Posts: 10,944
Received 42 Votes on 40 Posts
Originally Posted by kornbln View Post
I had a feeling the question about the jbox would come up. Like I said, it's only a rough sketch.. So here's some more detail.
The j-box isn't wrong; it's just atypical.

My plan is to install a jbox in front of the LB so I can transition from the NM to THHN/THWN.
That sounds like a correct course of action.

Just for my own curiosity, would it be code compliant to make the splices inside the LB?
It's a bit of a bizarre rule, but an LB can be used as a junction box if the cubic inch capacity is stamped into the body of the fitting by the manufacturer. Apparently if they calculate it on the drawing board it's okay, but if you do in the field it isn't.
 
  #10  
Old 04-06-09, 01:06 PM
Forum Topic Moderator
Join Date: Feb 2005
Location: Near Lansing, Michigan
Posts: 10,944
Received 42 Votes on 40 Posts
Originally Posted by Michael Thomas View Post
A business with illogically high liability
This is a bit offtopic for the original post, but I was just curious about your signature quote Michael. Isn't the liability of the home inspector typically limited to just a refund of the inspection fee (couple hundred bucks) in the event a major flaw was missed? I can't imagine the inspector bears any liability to actually fix problems or pay damages to a home buyer?
 
  #11  
Old 04-08-09, 08:41 PM
Banned. Rule And/Or Policy Violation
Join Date: Dec 2007
Location: Chicago
Posts: 1,011
Received 0 Votes on 0 Posts
Originally Posted by ibpooks View Post
This is a bit offtopic for the original post, but I was just curious about your signature quote Michael. Isn't the liability of the home inspector typically limited to just a refund of the inspection fee (couple hundred bucks) in the event a major flaw was missed? I can't imagine the inspector bears any liability to actually fix problems or pay damages to a home buyer?
You can write a a contract that disclaims liability for screwing up everything short of misreporting the direction from which the sun rises, but that doesn't stop someone from suing you, and defense is expensive - recently an inspector in California had his E&O insurance settle a suit rather than undertake the cost of defense in a case involving an accident at a swimming pool built months after the inspection!

The issue here is even if the inspector has not made a mistake, when something goes wrong there are certain number of people who are absolutely determined to have somebody else pay for it irrespective of the actual extent of their responsibility. They're going to go to court, and if you can settle with them for the cost of your E&O deductible, or for $5,000-$10,000 if you don't carry insurance, you've escaped the legal system about as cheaply as you can.

Even more frustrating - infuriating, really - are the people who file suit knowing that the inspector did not make an error, or who simply sue everyone involved in the real estate transaction on the grounds that in most cases everyone involved will pay a few thousand dollars rather than fight it out in court - that's what happened in the case of the inspector above.

A home inspector typically makes far less than the real estate agent and usually considerably less the lawyer involved in the transaction, neither of whom as a practical matter as much liability exposure, but the home inspector in my state is on the hook for the accuracy of their opinions for five years after the date of the report, and to protect themselves have have to carry quite expensive insurance (my E&O is around $3500 a year with a $5000 deductible) - IMO that's illogically high liability for the cost of the service provided.

If you think about it a really competent home inspection is remarkable undertaking: in three or four hours the inspectors is attempting to ascertain the condition of a very diverse collection of systems and components, and theoretically is legally held to a standard 100% accuracy.

Remarkably, really good inspectors come pretty close: competent inspectors are sued on the average only once every several thousand inspections, and often then the lawsuit is eventually found to be groundless. But In order to achieve that degree of thoroughness and accuracy the inspector not has to master an enormous body of practical knowledge, but they have to continually think very carefully about how to communicate what they discover, knowing that literally every word they say and write may be scrutinized in court.

And the fact remains that even if you are very, very good there is almost certainly some issue overlooked in virtually every inspection you perform - there is just not enough time available to perform the inspection without constantly making decisions about where to devote your limited time based on what you see, and inevitably that decision cannot always be correct.

I've never been sued - my assumption is the best protection against a lawsuit is to perform an inspection and write a report as close to perfect as possible. But eventually, the odds will catch up with me, to the tune of $5000 a pop.

There are few if any other participants in a real estate transaction routinely held to anywhere near those standards.
 
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
 
Ask a Question
Question Title:
Description:
Your question will be posted in: