Lots of 12/2 MC to land in 2 cans.

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J.P.

J.P.

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United States
I have 67 12/2 MC cables to land in two large panels. I would like to have it look neat.

My idea as of now is to run some strut horizontally and use 1" strut straps. It looks like 6 MC cables will comfortably fit in a strap.

I was concerned about " bundling " and not passing a rough in inspection.

As I understand it though you can put 10 MC cables together before bundling is a concern?

Any clarification would be much appreciated.

here is the code section i was looking at:

310.15(B)(4) Adjustment factors shall not apply to Type AC
cable or to Type MC cable under the following conditions:
a. The cables do not have an overall outer jacket.
b. Each cable has not more than three current-carrying
conductors.
c. The conductors are 12 AWG copper.
d. Not more than 20 current-carrying conductors are in-
stalled without maintaining spacing, are stacked, or are
supported on?bridle rings.?
(5) An adjustment factor of 60 percent shall be applied
to Type AC cable or Type MC cable under the following
conditions:
a. The cables do not have an overall outer jacket.
b. The number of current carrying conductors exceeds 20.
c. The cables are stacked or bundled longer that 600 mm
(24 in) without spacing being maintained
 
Since you're adjustment factor would be 60% you would be good to go providing that the load doesn't exceed 18 amps on each cable but none of those bundled cables can supply multiple receptacle loads. You cannot use the next size up rule with more than one receptacle on a circuit {240.4(B)(1)}.

30 * 60% = 18 amps, next size up OCPD 20 amps.
 
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16 A would be my max load for any given cable. They are intended to run multiple receps. I will look up your code reference.
Thanks for your input.
 
J.P. said:
16 A would be my max load for any given cable. They are intended to run multiple receps. I will look up your code reference.
Thanks for your input.
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You have to figure those circuit conductors @ 20 amps regardless of what your intended load may be, as per the mentioned 240.4(B). If you were not supplying receptacles, you could go with 16 amps on 20 amp overcurrent devices if that is all the load that is connected.
 
can you set a trough up high above the panels and make your panel runs in conduit. I have done this it makes a better appearance downfall is you have to make taps which are time consuming and you will have to derate still and use #10 possibly but then you only have maybe 7 or less conduits coming from your panels pending how you derate, conductor fill etc.
 
They also make mc straps that twist into versa bar .
It looks neat when you have slot of mc entering panels .

or the trough method looks good with three nipples
 
FREEBALL said:
can you set a trough up high above the panels and make your panel runs in conduit. I have done this it makes a better appearance downfall is you have to make taps which are time consuming and you will have to derate still and use #10 possibly but then you only have maybe 7 or less conduits coming from your panels pending how you derate, conductor fill etc.
Click to expand...

Keep nipples between trough and panel to less then 24 inches and you won't need to derate.

Column width panelboard with the pull box on top and gutter down to the panelboard sounds like a good candidate for such an installation. Neutrals can all land in a neutral bus located in the pull box as well.
 
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kwired said:
Keep nipples between trough and panel to less then 24 inches and you won't need to derate.

Column width panelboard with the pull box on top and gutter down to the panelboard sounds like a good candidate for such an installation. Neutrals can all land in a neutral bus located in the pull box as well.
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If you originate branch neutrals in a bar in the pull box, wouldn't you have to run all of the hots and the neutral feeder through the same nipple to avoid inductive effects from unbalanced currents?
Oh, OK, gutter would work too.
 
Or just use a standard panel run the MC directly into like the OP was planning. Save a ton of money and time.

I always love how quick people on forums are more than happy to spend others money.
 
John120/240 said:
Instead of 67 runs of 12-2 MC, I would of explored using 12-3 MC or 12-2-2 MC.
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I looked into getting some 12/9 mc, then setting a box on the end of it and breaking out from there. I decided against the octopus on the ceiling though. I have used a lot of that in hotels were one room needed a set amount of circuits. The 12/9 worked great for that.

In my application now I would have to run multiple cables to the same room and then have left over circuits in a majority of the second wire ran to each room. Seemed like a waste.
 
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