# Panel as a raceway



## brian john (Mar 11, 2007)

We have a site with a two (2) 480/277 VAC panel's sandwiched in between them is a 208/120 VAC panel, they have utilized the 208/120 panel as a raceway passing conductors from one 480/277 panel to the other 480/277 panel.

Any issues, there appears to be suficent space for the conductors.


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## Dennis Alwon (May 9, 2009)

Art. 312.8 allows this


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## Dennis Alwon (May 9, 2009)

The 2011 has made a change that requires labeling the conductors that pass thru with the location of their disconnect.


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## qckrun (May 18, 2009)

Dennis Alwon said:


> The 2011 has made a change that requires labeling the conductors that pass thru with the location of their disconnect.


Don't you have to put a 'raceway' between to the two to separate the voltages? A journeymen I worked with a long time ago stated this. I always wondered if it was true.


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## carryyourbooks (Jan 13, 2010)

qckrun said:


> Don't you have to put a 'raceway' between to the two to separate the voltages? A journeymen I worked with a long time ago stated this. I always wondered if it was true.


as long as the insulation is rated for 600v, they can go in the same raceway.


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## JRaef (Mar 23, 2009)

carryyourbooks said:


> as long as the insulation is rated for 600v, they can go in the same raceway.


I think the rule is that all conductors must have the same insulation rating, at the highest level in the enclosure. So ALL of the conductors in the 120/208V panel would need to be 600V rated. For the most part that's going to be true anyway, but you do have to make sure. I've never seen it myself, but a friend who does resi work said that he came across some el-cheapo Chinese imported NM cable that was only 300V rated.


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## backstay (Feb 3, 2011)

JRaef said:


> I think the rule is that all conductors must have the same insulation rating, at the highest level in the enclosure. So ALL of the conductors in the 120/208V panel would need to be 600V rated. For the most part that's going to be true anyway, but you do have to make sure. I've never seen it myself, but a friend who does resi work said that he came across some el-cheapo Chinese imported NM cable that was only 300V rated.


I don't have my book in front of me, but the "B" of nmb indicates 600 volt rating and I don't think you can use a lower rating. I could be wrong, but don't think so.


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## Dennis Alwon (May 9, 2009)

art.300.3(C)


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## JRaef (Mar 23, 2009)

backstay said:


> I don't have my book in front of me, but the "B" of nmb indicates 600 volt rating and I don't think you can use a lower rating. I could be wrong, but don't think so.


I thought the "B" meant the temperature rating of the cable is 90C. That may indeed make it 600V in all practicality however.

Hmmm... Article 334.104 seems to imply that NM cable is 600V, but the wording doesn't explicitly rule out a lower voltage. However I'd be willing to bet no legitimate mfr bothers making a lower rating.


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## Mshea (Jan 17, 2011)

YOU ARE ALLOWED TO RUN CONDUCTORS FROM 1 SYSTEM THROUGH A PANEL OF ANOTHER SYSTEM??????

Is this for real??

I'd take away your contractors licence if you did that in Canada.

Except where a piece of equipment needs supply from 2 systems that we allow the wires to share an enclosure and then only the fewest wires necessary. Think exiit light with a DC back up. only in the connection box may both systems share the box. Panels? no way except perhaps a shunt trip or breaker operator associated with controling the breakers.

This seems insanely dangerous. Turn off the 120 /208 panel and you have 480 volt conductors running through your panel?

Sorry this is nuts in my books.


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## brian john (Mar 11, 2007)

Mshea said:


> YOU ARE ALLOWED TO RUN CONDUCTORS FROM 1 SYSTEM THROUGH A PANEL OF ANOTHER SYSTEM??????
> 
> Is this for real??
> 
> ...


Well as a qualified electrician American obviously trust their electricians more that Canadians can, and understandably!
:laughing:

Who works on your ATS's, Switchgear and battery systems?


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## BBQ (Nov 16, 2010)

Mshea said:


> This seems insanely dangerous. Turn off the 120 /208 panel and you have 480 volt conductors running through your panel?
> 
> Sorry this is nuts in my books.


*Qualified Person.* One who has skills and knowledge related
to the construction and operation of the electrical
equipment and installations and has received safety training
to recognize and avoid the hazards involved.


I never assume there is only one source when working.


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## green light (Oct 12, 2011)

JRaef said:


> I thought the "B" meant the temperature rating of the cable is 90C. That may indeed make it 600V in all practicality however.
> 
> Hmmm... Article 334.104 seems to imply that NM cable is 600V, but the wording doesn't explicitly rule out a lower voltage. However I'd be willing to bet no legitimate mfr bothers making a lower rating.


 you are right. the b in nmb means it has a 90 deg rating


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## frenchelectrican (Mar 15, 2007)

Dennis Alwon said:


> The 2011 has made a change that requires labeling the conductors that pass thru with the location of their disconnect.


Merci for the heads up on that and for the conductors we do in France we do the same thing as well just make sure you mark them what they goes if feed thru ( the only time we do that is used on ATS or lighting panels with remote breakers ) 

Merci,
Marc


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## jefft110 (Jul 7, 2010)

Mshea said:


> YOU ARE ALLOWED TO RUN CONDUCTORS FROM 1 SYSTEM THROUGH A PANEL OF ANOTHER SYSTEM??????
> 
> This seems insanely dangerous.


Without sounding like Riveter..

Why?


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## Jlarson (Jun 28, 2009)

Mshea said:


> Is this for real??


I do it quite often. Especially for stuff like evap coolers where I need 480 and 120 to the same piece of equipment. I'll bolt the motor starter panel, 480 panel and 120/208 panel to each other with most of the sides cut out and edged with edging. 

Saves a lot of time and uses less material and looks better then a bunch of unnecessary J boxes or wireway.


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## RePhase277 (Feb 5, 2008)

Canadian NM has a 300 V rating.


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## Dennis Alwon (May 9, 2009)

Mshea said:


> YOU ARE ALLOWED TO RUN CONDUCTORS FROM 1 SYSTEM THROUGH A PANEL OF ANOTHER SYSTEM??????
> 
> Is this for real??


Well we are not in Canada but I would be interested in the code article that does not allow this. In the USA we cannot have devices of different voltage in the same box if the voltage exceeds 300V between conductors unless there is a barrier. We could have a 240V switch and a 120V switch in the same box. In terms of a jb with no devices we can have a 277v splice and a 120v splice. Of course color coding would have to be made at the panel a, as well as in the box, stating the different scheme for the different voltages.


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## RePhase277 (Feb 5, 2008)

The code says "adjacent devices". I have wondered how any re-arrangement could result in a compliant situation. I mean if two devices out of three in a box have more than 300 V between them, I can't see how any combination of re-arranging could change it.


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## Dennis Alwon (May 9, 2009)

InPhase277 said:


> The code says "adjacent devices". I have wondered how any re-arrangement could result in a compliant situation. I mean if two devices out of three in a box have more than 300 V between them, I can't see how any combination of re-arranging could change it.


It cannot in this situation so a divider must be used. That is what the graphic shows


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## BBQ (Nov 16, 2010)

InPhase277 said:


> The code says "adjacent devices". I have wondered how any re-arrangement could result in a compliant situation. I mean if two devices out of three in a box have more than 300 V between them, I can't see how any combination of re-arranging could change it.


It depends on the phases.

The voltage between phase B 120 and phase B 277 is less than 300 volts.


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## JRaef (Mar 23, 2009)

Dennis Alwon said:


> ... In the USA we cannot have devices of different voltage in the same box if the voltage exceeds 300V between conductors unless there is a barrier. ...


But what about an enclosed 480V motor starter with 120V control from a separate source? 480-120= 360V difference. Worse yet, 24V control...


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## don_resqcapt19 (Jul 18, 2010)

JRaef said:


> But what about an enclosed 480V motor starter with 120V control from a separate source? 480-120= 360V difference. Worse yet, 24V control...


The two rules that cover this issue are in the switch article and the receptacle article. The rules only apply to those devices,


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