MC vs EMT

[Alwayslearningelec]

Did a comparison. What are your thoughts?

Running 6- 1P 20A circuits from panel to a box two different scenarios. Both on a trapeze rack with straps.

(6) separate 12/2 MC cables from panel to a box 100’ away


Or


(1) 1” EMT conduit(only one bend) 100’ away with 13 #10’s


I thought it would be a lot quick to run the MC cable but the hours I come up with are about the same.

 

[infinity]

If you pulled all 6 cables at once it might be cheaper but you'll end up with 12 terminations (6 on each end) using MC versus 2 using EMT so I could see not much of a difference between the two methods.

 

[Alwayslearningelec]

If you pulled all 6 cables at once it might be cheaper but you'll end up with 12 terminations (6 on each end) using MC versus 2 using EMT so I could see not much of a difference between the two methods.

BTW how many 12/2 MC cables is practical to pull at once? Steel armor.

 

[infinity]

BTW how many 12/2 MC cables is practical to pull at once? Steel armor.

Good question. Since you mentioned pulling over racks you could easily pull 3 at once.

 

[LarryFine]

(6) separate 12/2 MC cables from panel to a box 100’ away

Or

(1) 1” EMT conduit(only one bend) 100’ away with 13 #10’s

How bout two 1/2" runs with only three circuits (7 #12s w/egc) in each run?

You can place the two far end boxes in different places, and avoid derating.

 

[Alwayslearningelec]

How bout two 1/2" runs with only three circuits (7 #12s w/egc) in each run?

You can place the two far end boxes in different places, and avoid derating.

3/4" min size that can be used per specs.

 

[LarryFine]

3/4" min size that can be used per specs.

Okay, two 3/4" runs. Still allows smaller wire, J-boxes, and fewer colors or spools of wire.

Six runs of MC cable would be rough to pull whether simultaneously or one at a time.

 

[Eddie702]

It depends how good you want the MC cable to look. Same reason I dislike PVC versus EMT more straps take time to keep it straight.

 

[infinity]

I thought it would be a lot quick to run the MC cable but the hours I come up with are about the same.

We would always run 1" or 1¼" EMT homeruns for this reason. At the end of the day it can be easier especially if you leave some room in the raceway for future circuits to be pulled in. Nothing worse than try to snake MC cable homeruns over a Sheetrock ceilings after everything is closed up and painted.

 

[Alwayslearningelec]

Okay, two 3/4" runs. Still allows smaller wire, J-boxes, and fewer colors or spools of wire.

Six runs of MC cable would be rough to pull whether simultaneously or one at a time.

I'm not exatly sure what you mean when you say smaller wire, j boxes and spools of wire making emt easier.

 

[infinity]

I'm not exatly sure what you mean when you say smaller wire, j boxes and spools of wire making emt easier.

He's saying that with two raceways you can run #12 AWG instead of a single raceway with #10 AWG. Personally I'd opt for the single 1" and the #10's.

 

[Sandlamb]

Why are you using 10’s if it’s conduit but 12 if it’s MC


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[MyCleveland]

Okay, two 3/4" runs. Still allows smaller wire, J-boxes, and fewer colors or spools of wire.

Six runs of MC cable would be rough to pull whether simultaneously or one at a time.

Shop I worked for (lifetime ago) preferred this method.
End boxes were set first...different team working on homeruns, while others could capture a cct and start branch wiring across the floor.

Doesn't the rack count go up significantly for MC homeruns?

 

[Seven-Delta-FortyOne]

Why are you using 10’s if it’s conduit but 12 if it’s MC


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Derating

 

[Alwayslearningelec]

Shop I worked for (lifetime ago) preferred this method.
End boxes were set first...different team working on homeruns, while others could capture a cct and start branch wiring across the floor.

Doesn't the rack count go up significantly for MC homeruns?

Ah...great point. Need to support every 6' for me as opposed to 10' emt.

 

[infinity]

Why are you using 10’s if it’s conduit but 12 if it’s MC

Yes as 7D41 said derating. 12 CCC's with #12's is only good for 15 amps. 12 CCC's with #10's is good for 20 amps.

 

[LarryFine]

I'm not exatly sure what you mean when you say smaller wire, j boxes and spools of wire making emt easier.

You can use #12 wires instead of #10, you can use smaller J-boxes, and the set-up and pull is easier.

If you run twelve (13) wires in one conduit, you need to set up twelve (13) spools to pull them all in.

If you run twelve (14) wires in two conduits, you only need to set up six (7) spools to pull them in.

 

[robertd]

Why are you using 10’s if it’s conduit but 12 if it’s MC


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Derating for more than 3 CCCs.

 

[infinity]

If you run twelve (14) wires in two conduits, you only need to set up six (7) spools to pull them in.

Yes that can save you having to set up 13 reels. You can also make two pulls in the 1" EMT.

 

[LarryFine]

I don't expect anyone to follow my suggestions. They're just alternatives to consider and price.

I tend to look at jobs from the installation point of view as a crew of one, perhaps with one helper.