THHN/Conduit/Jbox question


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Old 10-27-17, 07:28 PM
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THHN/Conduit/Jbox question

Evening all,

I am in the process of wiring up my garage with a subpanel. On one wall I have two 110 circuits, two lighting circuits running down to swtiches, and one 220 circuit (15 total wires).

I installed 1/2" EMT in two runs from the panel to the wall. One for the lighting circuit and one for the 220/110 outlets, 9 wires in one, 6 in the other. I was able to get the two lighting and 110 circuits pulled okay. However, due to the bends (four/360 degrees total) I just cant get that 220 circuit pulled. What I am wanting to do is run one 3/4 conduit from the panel to a jbox that would then feed the two 1/2 conduits.

According to this chart I can fit the 15 #12s in a 3/4 EMT. https://solutions.borderstates.com/r...it-fill-table/

What I dont know is if there is any issue with running 15 wires into a 4x4 jbox.

As to why I am running 12 ga for lights, I just figured I'd only have to buy one spool of each wire. Maybe I downsize the lights to 14 and run those and the 220 circuit together and then maybe I can fit it all with what I have currently.

Here's my current setup:



Here is what I am thinking of doing:



Thanks for your time. Any help appreciated.
 
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Old 10-27-17, 07:36 PM
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Nice pipe work!

I must be missing something. I only see three 90's in your conduit system.
 
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Old 10-27-17, 07:54 PM
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Thanks! First time. Took some trial and error.

There are four. Up from the panel and out from the wall is one, then it turns to the left for two, then right towards the other wall for three and then at the other wall it turns down for the fourth.
 
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Old 10-28-17, 05:19 AM
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I must be missing something. I only see three 90's in your conduit system.
.
There are two bends above the panel.

The issue with running 15 conductors in a pipe is you will have to derate them to 50%. That makes a #12 conductor only good for 12.5 amps. You are better off running separate pipes and keeping the current carrying conductor count to 9 or less.

Another issue I see is you have 3 - 1/2 conduits running to the same 4x4" box. That box will surely be over filled. An 1.5" deep 4x4" box can only have 9 wires in it. If it is a deep 4x4" it is only 13.

Suggestions:
Run one pipe for the horizontal tool run to to the box just right of the chop saw.
Try to stay to 3 - 90 max or add boxes instead of 90's
You are running a metallic wiring method. The ground wire is redundant to the conduit system.
Unless the shop is very large you likely only need on lighting circuit.
Run multiwire circuits. You will then only need one neutral per two hot conductors. (use 2 pole breakers)
Add an 11b (4 11/16 square) box above the panel of ease of pulling/pushing wires.
 
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Old 10-29-17, 10:14 AM
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On one wall I have two 110 circuits, two lighting circuits running down to swtiches, and one 220 circuit (15 total wires).

Those would be 120 and 240 volt circuits.
 
 

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