Dimmers' detrimental effect on sound quality - Page 2 - AVS Forum
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post #31 of 46 Old 01-16-2011, 05:49 AM
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Even though I have no experience in residential wiring, I do have over a quarter century in the electrical field. I don't believe I've ever seen a neutral taken to a switch that didn't need it. It's not done. The NEC article referenced still does not require it. In essence, it states that if there's no way one could ever get to the box to get a neutral there, then yes..a neutral is required. That said, everything is accessible to varying degrees.

So, a neutral is not needed for cancellation of parasitic magnetic heating, and it not required as long as someone could install one at a later time. Thus, as I stated several posts ago, unless the device requires a neutral, you don't take the neutral to the device.


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post #32 of 46 Old 01-16-2011, 10:57 AM
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2005 NEC 200.7(C)(2) permits re-identifying an ungrounded white (or gray) conductor in a cable when it's used as the supply ("hot") in a single-pole, 3-way or 4-way switch loop.

The exception mentioned in the Mike Holt reference above ("Switch loops shall not require a grounded conductor.") is actually part of NEC 404.2(A); it is not just Mr. Holt's interpretation. 404.2(A) refers specifically to 3-way and 4-way switches but 200.7(C)(2) also includes single-pole and certainly indicates that it's permissible to use a two-conductor (W/G) cable for a single-pole switch loop if the white (gray) conductor is re-identified.

Apparently this may change in the future (with exceptions) according to the reference. Is the 2011 code formally out now? Has it been adopted anywhere?

Just because something is not required doesn't mean it's prohibited, though, so it's OK to provide a neutral even if it isn't absolutely required, but with extra conductors, among other things you do have to consider box fill constraints. And, as already pointed out, your local AHJ can be more (or less) restrictive than the NEC if they desire, and/or may have officially adopted an older version.
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post #33 of 46 Old 01-16-2011, 01:11 PM
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2011 NEC has been published. Jurisdictions have their own adoption cycles. My state is on a three year review cycle, so we are always a couple of years behind the latest edition.

The problem here is that there is no specific exception in 300-3(b) for switch loops, but there are other sections that could be interpreted as allowing it. Mike Holt, who certainly knows more about the NEC than your average AHJ says its OK. Some AHJs agree, some don't. It seem that sometimes this is simply because a lot of AHJs go by what they have been taught as good practice, even though it is not in the NEC or the local amendments.
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post #34 of 46 Old 01-16-2011, 05:03 PM
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Quote:
Originally Posted by Rasterfarian View Post

...........Just because something is not required doesn't mean it's prohibited, though, so it's OK to provide a neutral even if it isn't absolutely required, but with extra conductors, among other things you do have to consider box fill constraints.........

You're absolutely correct, the NEC is a minimum. When in school, learning to use the NEC, there exist 3 key aspects. Shall, Should, and the code is a minimum. However, contractors do not install something out of the goodness of their heart. If one doesn't spec an install in a certain manner, it doesn't get done. A contractor will put in a job in the cheapest way possible, both adhering to Code, and any specs. If a rogue individual takes it upon their self to do something like this without permission, their job is in jeopardy. That's electrical contracting. The savvy client, money permitting, specs accordingly.

Good discussion, I've certainly learned something. All I asked, many posts ago, was "why in the world would you take a neutral to a switch?"



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post #35 of 46 Old 01-16-2011, 06:23 PM
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Most proficient electricians would not use ceiling boxes as a Jbox for the branch circuit feed from the panel and then make drops from the ceiling to the associated outlets and switches. For proficiency, cost savings in labor and materials, not to mention most inspectors, most electricians make branch feeds into the first box physically closest to the panel as far as cable runs are concerned, be that an outlet or wall switch(es) box.

They drop off loops to each outlet and switch as permitted. What possible benefit would there be in using a ceiling box as a J-box (which was quite common in K/T wiring) if there are other taps on the branch circuit? Using a switch or outlet box is MUCH easier and less time consuming and most inspectors (especially here in SoCal) require it.

You will use the same amount of cable for a switch loop as you would for a switched hot and neutral feed from the switch box.
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post #36 of 46 Old 01-16-2011, 07:59 PM
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Quote:
Originally Posted by Gizmologist View Post

Most proficient electricians would not use ceiling boxes as a Jbox for the branch circuit feed from the panel and then make drops from the ceiling to the associated outlets and switches. For proficiency, cost savings in labor and materials, not to mention most inspectors, most electricians make branch feeds into the first box physically closest to the panel as far as cable runs are concerned, be that an outlet or wall switch(es) box.

They drop off loops to each outlet and switch as permitted. What possible benefit would there be in using a ceiling box as a J-box (which was quite common in K/T wiring) if there are other taps on the branch circuit? Using a switch or outlet box is MUCH easier and less time consuming and most inspectors (especially here in SoCal) require it.

You will use the same amount of cable for a switch loop as you would for a switched hot and neutral feed from the switch box.

Maybe, maybe not. It depends on where the feed is coming from relative to the ceiling box and the switch, and where it goes from there - if anywhere. There may not be any other taps on the branch circuit, or only other ceiling boxes (with or without their own switch). If you need the same amount (or less) cable and labor for a switched hot and neutral, I doubt you'll see a switch loop. In many places (I'd bet most, or nearly all, but can't actually say for sure), if it saves cable and/or labor, you'll see the feed going to the ceiling box and then a switch loop. Switch loops are quite common; if they didn't save cost, they wouldn't be.

If switch loops are not permitted in SoCal, so be it. It's their right to declare so even if NEC permits, period.
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post #37 of 46 Old 01-16-2011, 09:07 PM
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In a residence, what type of circuit load do you see in a ceiling fixture that does NOT have a switch loop and EVERY room in the living spaces MUST have outlets. Where is the supposed savings.

BTW having worked in Texas, CA, and Washington, I have yet to see any new work using the ceiling fixture as a room J-box. I HAVE seen it in older homes but given the heat rise, the difficulty of working over your head, the limited size of a ceiling fixture box, it simply makes NO sense at all.
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post #38 of 46 Old 01-17-2011, 08:44 AM
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Quote:


In a residence, what type of circuit load do you see in a ceiling fixture that does NOT have a switch loop and EVERY room in the living spaces MUST have outlets.


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post #39 of 46 Old 01-17-2011, 07:10 PM
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Quote:
Originally Posted by Gizmologist View Post

In a residence, what type of circuit load do you see in a ceiling fixture that does NOT have a switch loop and EVERY room in the living spaces MUST have outlets. Where is the supposed savings.

I'm not following that first part, either, but I see plenty of opportunities for savings. Receptacles (if that's what you mean by "outlets") are not always on the same circuit as the lights in a room; sometimes it's not even allowed, so no reason to even associate with the lights across the board.
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BTW having worked in Texas, CA, and Washington, I have yet to see any new work using the ceiling fixture as a room J-box. I HAVE seen it in older homes but given the heat rise, the difficulty of working over your head, the limited size of a ceiling fixture box, it simply makes NO sense at all.

Not even in rooms with multiple overhead lights? Are you saying that all the overhead lighting outlets are always connected directly to the switch, rather than from one to the next, even if the switch is at the far end of the room and another light is (much) closer than the switch? Now *that* makes no sense. There arel deep octagon boxes, and also extensions, so volume isn't that big an issue.

Google "feed at light" (exact phrase in Advanced Search, or use the quotes for an all-the-words search). The Electrical Wiring Residential: Based on the 2005 National Electric ... by Ray C. Mullin result shows an example of the switch loop we're talking about - including the splice in the hot at the ceiling box. It's a legal and well accepted practice (at least in a lot of - probably most - places), and not uncommon. Heck, the reason this thread has gone into this discussion at all is because there's often not a neutral, and no requirement for one, at the switch box.
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post #40 of 46 Old 01-17-2011, 08:41 PM
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Wiring is generally run from the panel to the the control point FIRST (switchboxes) and THEN to the loads. Runs across the joist are kept to a minimum so wiring is in the walls as much as possible.

Even in the case of multiple light fixtures, the switch is still part of the circuit and the jumping from one fixture to the next in a loop configuration is common. However, the feed or the switch loop still has to get to the switch. Since the same amount of cable will used regardless of were the feed originates, what savings are realized by running the panel feed to the light fixture and then creating a switch loop that must be re-identified as a switch leg?

Would you rather deal with a hot feeder standing on a ladder, working over your head or open up a switch box where all the circuits and leads are easily worked?

Do what ever make you happy but be prepared for a yellow tag here.
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post #41 of 46 Old 01-18-2011, 07:49 AM
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Quote:
Originally Posted by Gizmologist View Post

Wiring is generally run from the panel to the the control point FIRST (switchboxes) and THEN to the loads.......


This is inaccurate.

Look, there are many reasons why you feed the fixture first...,then drop a hot and return down to the switch. The words you use indicate that you have some knowledge in this regard, however the manner in which you use them illustrates this is something that you're not intimately familiar with. You're mis-using terminology, you're insisting on things that are not generally performed in a way in which you describe. I don't understand why you're insistent, and clearly you're not well versed in this subject.

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post #42 of 46 Old 01-18-2011, 10:30 AM
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You have no experience in residential wiring. Perhaps you should talk to the electricians who DO have years in residential. Then you will understand.

Industrial and commercial power/control/monitoring circuitry is NOT handled the same.

I work in residential now (semi retired) and have worked many years repairing and upgrading large hotel ballroom dimmer and sound systems in the professional audio visual presentation business in Washington, DC Dallas and Ft Worth Texas, several here in SoCal and in Seattle.

I have been in the business for over 40 years.

Enough said, and for me, subject closed. Do what you wish.
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post #43 of 46 Old 01-18-2011, 02:39 PM
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I 100% stand by my contention that what you are saying is incorrect. Period. Not even a grey area.





The level of my experience is in residential home wiring, or even how many years in the industry, still all that has zero impact on how electricians wire a light fixture, and switch from a panel.

This is simple, and very clear. One does not go from the circuit breaker in the panel, directly to the light switch, as you insist. This is not generally done, and my only guess is you've perhaps seen this and assumed it is normal. This is not normal.

I'd be happy to explain the various implications, and why this is so important, but I don't believe anyone cares. If so, anyone can contact me, and I'll elaborate.




Thanks and I'm sorry for any mis-understanding.

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post #44 of 46 Old 01-18-2011, 03:41 PM
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Response from the first was " ummmmm..... yea. And this guy does what?"

Response from the second was" OK, I would like this ******* to come to any home being built today and tell me or any of the crews that "it simply is not done". BS. Sure it will work either way, but for us, time is money and we do it right, on time , and why on earth would I make multiple runs to a damn box in an 8 ft ceiling? In case this guy has no clue, we run a 14-3 from the switch to the ceiling for a fan/light combo and also branch off the same feed if we can to run the outlets. I guess he doesn't see that. Our guys can do a horizontal run through studs a hell of a lot faster since the same hole layouts feed back to back rooms and we know where every cable is. Nobody worth his salt runs across the joists for all the drops. Guy's crazy."

OH well, have fun YOUR way. the rest of us will do it right. NOW I am done with you. Have a nice night and a cold beer.
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post #45 of 46 Old 01-18-2011, 04:15 PM
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Have a nice night and a cold beer.

No disagreement there! Cheers!
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post #46 of 46 Old 01-19-2011, 04:52 PM
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Now that NEC2011 is starting to become available, I see that Articles 404.2 and 404.9 have changed with respect to neutral. Exactly what this will mean is a subject of debate on the Mike Holt rules forum.

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