Using EMT to create a path for flush mount panels

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cadpoint said:
Now what size ground do run to the panel ? And not using EMT is a Ground !
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If 12 AWG is the largest conductor (protected by a 20 amp overcurrent device) entered into the trough/wireway (load side) and they are all terminated on a grounding terminal, the largest equipment ground required from the panel to the wireway would only be required to be a 12 AWG.

250.122(C) Multiple Circuits.
Where a single equipment grounding conductor is run with multiple circuits in the same raceway or cable, it shall be sized for the largest overcurrent device protecting conductors in the raceway or cable.
 
cadpoint said:
Now what size ground do run to the panel ? And not using EMT is a Ground !
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That depends entirely on the largest circuit, most times the EGC would end up being 10 AWG.

I would have no problem using the EMT as the ground path but the job specs often require a copper EGC.
 
TOOL_5150 said:
Man, that MC goes all the way up to 10/16 !! Thats one heck of a trunk. A spool of that must cost thousands....


~Matt
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I have only used up to 10/8, a thosand footer has a bit of weaight to it as well. :grin:

But if you have a bunch of locations that each need mutliple circuits you can not beat it.
 
iwire said:
I would have no problem using the EMT as the ground path but the job specs often require a copper EGC.
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Hmmm. Do they make copper EMT? :grin:

iwire said:
But if you have a bunch of locations that each need mutliple circuits you can not beat it.
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Hey, a sub-panel in a cable. ;)
 
Bob Kraemer said:
Don't feel lonely, Day Quill & Night Quill are my favorite fluids right now besides beer.:grin: :mad:
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Have you tried "Alka-Seltzer PLUS cold medicine, Nighttime formula?" Makes the original Ny-Quil look like baby aspirin.
 
JohnME said:
I have 2 panels, flush with the finished wall, I cannot get behind, or to the side of these panels. I want to create future access, and plan on running a 2" EMT pipe up 2 feet with a stub 90 and hit a metal wireway (trough) above a suspended ceiling.

To make a long story shorter, Can I enter my metal wireway with MC, strip the metal jacket off, and then run the wire down the pipe to the panel? I would rather do it this way to avoid pulling THHN, and splicing, but cant seem to find a section in the book to tell me yes or no. I will also have to up my pipe size, or run a more than one.

Or, if anyone else has an easier way, without fishing all the MC cables down the wall, I would be up for that as well.
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If these are 42 circuit panels, why don't you stub 6 1" EMT's, 3 from each side of the loadcenter. Then you can run all the odd numbered circuits down the left 3, and the even down the right.
 
LarryFine said:
Hey, a sub-panel in a cable. ;)
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Pretty much :smile:



The real drive for us to use these cables are modular office furniture, many times we need to provide two complete 3 phase 4 wire circuits to each of many locations.
 
brandon2177k said:
Forgive my ignorance, thought you meant romex, guess I knew somewhere in my head that MC could come that way.
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Don't worry...I wouldn't classify that as "ignorance" because I believe that ignorance comes from ignoring the facts. Sometimes that leads to "arrogance" if you aren't careful.

You merely weren't yet educated. From my experience on this forum, "not yet educated" is completely accepted by the members here. The more you learn, the more you know. The more you know, the more you learn.
 
iwire said:
Pretty much :smile:



The real drive for us to use these cables are modular office furniture, many times we need to provide two complete 3 phase 4 wire circuits to each of many locations.
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Yes, and on a 40 or 60 story buildings, you may use thousands of feet of both, the super neutral, and multi wire MC cables, for everything from, office cubes, to lighting circuits, and we used the method Bob described, many times.

They treat the small electric rooms, in these high rise buildings, like an expensive peace of real estate, so you may need to plan your cable runs, as not to steal space from the rooms.
 
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Hey Thanks

Hey Thanks

Honest, I thought I did know that to be the correct application !
I can only recall running into distrubition panels and boxes with a larger ground wire. Gezz, thats it I just don't trough enough, where's the tap tool! :rolleyes:
 
Ended up ripping the 2x4's down and running all the cable into the top of the panels. Done deal. Will add a few 3/4" conduits for anything we might miss or they might want to add.
 
Adjustment factor?

Adjustment factor?

TOOL_5150 said:
Man, that MC goes all the way up to 10/16 !! Thats one heck of a trunk. A spool of that must cost thousands....


~Matt
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So if you used 10/16 MC would you need to adjust the ampacities using table 310.15(B)(2)(a)?
 
The Iceman said:
So if you used 10/16 MC would you need to adjust the ampacities using table 310.15(B)(2)(a)?
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Yes, assuming it's used for four - 3 phase 4 wire circuits you would have 12 (or maybe 16) current carrying conductors either way that is a 50% downward adjustment.

For 20 amp circuits you would have use 10 AWG.

10 AWG is rated 40 amps, 50% of that is 20 amps. :cool:
 
iwire said:
Yes, assuming it's used for four - 3 phase 4 wire circuits you would have 12 (or maybe 16) current carrying conductors either way that is a 50% downward adjustment.

For 20 amp circuits you would have use 10 AWG.

10 AWG is rated 40 amps, 50% of that is 20 amps. :cool:
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But 310.15(B)(2) Exeption No.5.(2) Adjustment factors shall not apply to MC if the conductors are 12AWG copper. So is 12 AWG ok for 20 amps? And do you need to adjust 10 AWG at 50% and still get 20 amps? Or am I reading this wrong?:confused:
 
iwire said:
310.15(B)(2) Exception No.5.(1) means that exception will not apply
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Exeption No.5(1) If each cable has not more than 3 current-carrying conductors then the exeption will not apply but in this case 12/16 we have more than 3 ccc. Exeption No.5(2) we don't adjust MC 12 AWG, but we do if its 10/16?
 
The Iceman said:
Exception No.5(1) If each cable has not more than 3 current-carrying conductors then the exception will not apply but in this case 12/16 we have more than 3 ccc. Exception No.5(2) we don't adjust MC 12 AWG, but we do if its 10/16?
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You can only use the Exception 5 with cables counting less less then 3 current carrying conductors.

Like a 12-2, or 12-3 or in some cases 12/4.


Or am I totally missing something? :smile:
 
iwire said:
You can only use the Exception 5 with cables counting less less then 3 current carrying conductors.

Like a 12-2, or 12-3 or in some cases 12/4.


Or am I totally missing something? :smile:
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Ok I understand. It seems like a confusing way of saying MC with over 3 ccc you shall use table 310.15(B)(2)(a).
 
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