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Tony Furst wrote:What you have to realize is that to apply that specific section and example from the NEC requires that you follow each and every rule and reference that 210.4 designates.
To explain in detail here how to properly install and wire a multi-wire circuit in this forum would be next to impossible as well as not having explicit and direct knowledge of the actual installation location I would not personally or professionally try to do do so.
Based on keeping people safe and making sure that the average homeowner not attempt something that can easily be installed incorrectly I don't recommend using the described and detailed method.
While the NEC does allow multi-wire circuits, with the new Arc fault requirements this won't work because they are not producing AFCI breakers with a common trip.
Tony
Tony, I do agree with your points above. I guess I was confused by your earlier posts saying that it was a serious code violation, etc.
Later. . . . . . .. . Brad
____________________ NEC 408.41 - ONLY exception is parallel conductors!
bdeditch wrote: Thats understandable, but is it a lot of work to replace the neutral and grounding bars to have more wires?
Like David said, can you double up on the grounds (if your panel is rated for that) to make room for some more neutrals? That would be the easiest thing to do. I can't tell for sure from your picture, but it looks possible. You could maybe mount a grounding bar to the can below the current two bars and move all your grounds to that, but I can't make that call from a picture without knowing more details. Also, it doesn't look like there is too much room to work there in your panel.
Later. . . . . .. . Brad
____________________ NEC 408.41 - ONLY exception is parallel conductors!
BadWolf wrote: bdeditch wrote: Thats understandable, but is it a lot of work to replace the neutral and grounding bars to have more wires?
Like David said, can you double up on the grounds (if your panel is rated for that) to make room for some more neutrals? That would be the easiest thing to do. I can't tell for sure from your picture, but it looks possible. You could maybe mount a grounding bar to the can below the current two bars and move all your grounds to that, but I can't make that call from a picture without knowing more details. Also, it doesn't look like there is too much room to work there in your panel.
Later. . . . . .. . Brad
Theres lots of room Brad. Thats why I asked if it was abig job. You can see the Ground behind it . I think I would just spend the afternoon changed all of them back. Have to do it before the weather gets to hot so the AC would not be off for hours.
The challenge you have is really how comfortable you are working in your panel. You may be able to replace both the neutral and ground buss bars but you will have to determine first if you can get ones of the proper size and configuration to meet the manufacturers requirements as well as not void the UL rating.
Thats the reason I suggested adding a sub panel or replacing your existing panel with one of greater breaker capacity. To change out the panel is a rather simple task and one that would give you much greater long term flexibility.
As for your neutrals and grounds, the grounds can be doubled up on their own buss but each neutral must be terminated under it's own screw unless the buss bar is specifically designed for multiple wires under each terminal. I can't tell from the picture if your neutral buss is rated for more than one wire.
Tony
Last edited on Monday March 31st, 2008 11:34 pm by Tony Furst
____________________ Do not meddle in the affairs of dragons, for you are crunchy and taste good with ketchup.
The whole idea of two neutrals under one screw just sounds like a service headache waiting to happen.. Yes, it should be more obvious that if the screw is to be loosened, there are two breakers that must be turned off, but it would seem to me that in some panels, there is either considerable difficulty identifying the second circuit, or even risk of failing to correctly identify it. Often the one you are working on, you have the advantage of it being new install, or you are removing it to replace it. Having it out of the clamp at the box entry can make identification much easier...
Tony Furst wrote:
As for your neutrals and grounds, the grounds can be doubled up on their own buss but each neutral must be terminated under it's own screw unless the buss bar is specifically designed for multiple wires under each terminal. I can't tell from the picture if your neutral buss is rated for more than one wire.
Look at the manufacturers data tag for the panel and it should tell you if the neutral bar is rated for multiple wires under the same terminal. If the data tag doesn't tell you you can go to the manufacturers website and see if you can get the cut sheets for your particular model.
Tony
____________________ Do not meddle in the affairs of dragons, for you are crunchy and taste good with ketchup.
You are not allowed by the NEC to double up on neutrals, unless maybe you are in an area that does not follow the NEC.
(This is pretty much the same message I posted the last time you asked about doubling up the neutrals, http://planetchristmas.mywowbb.com/forum73/22642.html but I've since found that if I use Internet Explorer I can insert links.)
A few weeks ago I attended a 2 day seminar on the 2008 code changes, and this exact question came up. Someone asked if you could double up neutrals on the bus bar and the trainer / inspector (Joe Tedesco, http://joetedesco.org/) said NO in no uncertain terms. To me, the NEC 408.41 clearly states that it's not allowed. Also, if you look at the panel labeling, they will say that a grounding conductor (not grounded) may be doubled. (Depending on the panel, I guess some may not allow doubling at all). Yes, many electricians double the neutrals, and inspectors pass it. That does not make it right!
Here is a quote from one of the messages in the above link, in case you don't click it:
Some electricians (who haven't done their homework) will tell you that it is OK to have more than one neutral (white) wire under a screw on the bus bar. They are wrong. It has long (at least as far back as 1967) been required by manufacturer's instructions and Underwriters Laboratories Standard 67 for panelboards.
You can also google "nec 408.41 violation" (without quotes) and find a bunch of stuff about the topic.
Later. . . . . .. . Brad
____________________ NEC 408.41 - ONLY exception is parallel conductors!
BadWolf wrote: You are not allowed by the NEC to double up on neutrals, unless maybe you are in an area that does not follow the NEC.
(This is pretty much the same message I posted the last time you asked about doubling up the neutrals, http://planetchristmas.mywowbb.com/forum73/22642.html but I've since found that if I use Internet Explorer I can insert links.)
A few weeks ago I attended a 2 day seminar on the 2008 code changes, and this exact question came up. Someone asked if you could double up neutrals on the bus bar and the trainer / inspector (Joe Tedesco, http://joetedesco.org/) said NO in no uncertain terms. To me, the NEC 408.41 clearly states that it's not allowed. Also, if you look at the panel labeling, they will say that a grounding conductor (not grounded) may be doubled. (Depending on the panel, I guess some may not allow doubling at all). Yes, many electricians double the neutrals, and inspectors pass it. That does not make it right!
Here is a quote from one of the messages in the above link, in case you don't click it:
Some electricians (who haven't done their homework) will tell you that it is OK to have more than one neutral (white) wire under a screw on the bus bar. They are wrong. It has long (at least as far back as 1967) been required by manufacturer's instructions and Underwriters Laboratories Standard 67 for panelboards.
You can also google "nec 408.41 violation" (without quotes) and find a bunch of stuff about the topic.
Later. . . . . .. . Brad
No I agree Brad, I never thought it would be a good idea to double up neutrals. Ground wire I feel could in certian cases. But like I mentioned before, its just thr fact I have no more room, except for 2 more breakers, to attach the neutral wires to the bus bar. This is why I asked if I could run a 3-12 and have the room for 3 breakers instead of only 2. When I seen the diagram as you attached, I still look at it and think that the neutral would, if I had something plugged into both plugins, would be shooting 240volts (combined) thru the neutral wire. Or is this not true?
Not to belabor the point but the NEC lists one very specific exception to the one neutral per terminal requirement and that is as follows:
408.41 Grounded Conductor Terminations.
Each grounded conductor shall terminate within the panelboard in an individual terminal that is not also used for another conductor.
Exception: Grounded conductors of circuits with parallel conductors shall be permitted to terminate in a single terminal if the terminal is identified for connection of more than one conductor.
Quite simply what this means is that if the manufacturer of the panelboard has installed a neutral terminal buss bar that is designed, rated and listed specifically for multiple wires under a single terminal it is legal. Now the cold hard reality is that it is not a good idea but it is approved by the code but only if the buss bar is specifically listed.
I have attended several of Mr. Tedesco's seminars and find him to be very informative but also very opinionated regarding his interpretation of the NEC and what the NFPA intended when they wrote it. That does not make him right or wrong in any way and I am not saying that he is wrong. Just simply stating the facts about what is actually in 408.41.
As for 240 VAC on the neutral no that won't happen from any hot phase to neutral you only have 120VAC potential, the only time you have 240VAC is phase to phase.
Tony
Last edited on Wednesday April 2nd, 2008 12:01 am by Tony Furst
____________________ Do not meddle in the affairs of dragons, for you are crunchy and taste good with ketchup.
Barry, the neutral will still be neutral. The load it carries in this configuration will never be more than that of one phase / outlet. The neutral carries the difference in the current draw. For example if one outlet is drawing 15 amps and the other is drawing 10 amps, the neutral will be carrying 5 amps.
Later. . . . . . Brad
____________________ NEC 408.41 - ONLY exception is parallel conductors!
Tony, we almost agree. What is stopping me is that the exception only applies to "parallel conductors."
310.4 Conductors in Parallel.
(A) General. Aluminum, copper-clad aluminum, or copper conductors of size 1/0 AWG and larger, comprising each phase, polarity, neutral, or grounded circuit conductor shall be permitted to be connected in parallel (electrically joined at both ends).
Notice that parallel conductors are electrically joined at both ends, and apply to 1/0 or larger conductors. (There are some exceptions, but none apply to small branch circuits that we are talking about.)
Later. . . . . . . .. Brad
____________________ NEC 408.41 - ONLY exception is parallel conductors!
Yes, it should be more obvious that if the screw is to be loosened, there are two breakers that must be turned off, but it would seem to me that in some panels, there is either considerable difficulty identifying the second circuit, or even risk of failing to correctly identify it. Often the one you are working on, you have the advantage of it being new install, or you are removing it to replace it. Having it out of the clamp at the box entry can make identification much easier...
