- Joined
- Sep 22, 2010
- Messages
- 7,223
"Questions on conduit sizing and install
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I am wiring in my phase converter. I have a couple of questions about using conduit and would like some advise and opinions.
When the house was built, I had the electrical contractor install a 100 amp sub panel in the garage. It is an oversize 3 car that will serve as my shop and is attached to the house. The panel face is flush with the drywall and the depth of the box is in the wall.
I went to the local electrical supply place and bought a 2011 NEC book, and I think I am tracking on everything OK, but I want everything to be done right the first time so I am seeking some advise.
I have an American Rotary 15 hp RPC. American Rotary says to use 4 ga copper wire for the supply. I am good with that, but it means I will need to run the supply wires through conduit as I can only find 4 ga copper in single stranded wire.
My converter panel will ideally be about 12 feet from the sub panel to get things laid out they way I would like them. Both panels will be mounted on the same wall, a straight run with no corners, windows, doors or anything between them. The garage is complete, so I think it would be very difficult to run EMT conduit through the studs (2x6 BTW).
Here are some questions. What I came up with sizing the conduit came out to 1" EMT. That was 3 wires, THHN 4 ga. A buddy of mine said I need 1 1/4 conduit. I think bigger would be better and I don't mind spending the extra money, but I am thinking 1 1/4 might be a little harder to work with.
How would you guys go about this? This is what I am leaning toward. Should I come out of the sub panel, (behind the drywall) with EMT conduit, come straight down and come out of the wall at the bottom near the floor, 90 degree it and run along the surface of the drywall until I am under the panel, junction box it and then go up into the bottom of the RPC control panel. The panel will be surface mounted of course.
A second option that I kicked around with my buddy is to use flexible metal conduit and bore holes in the studs. Keep everything behind the drywall, come into the control panel from the back so nothing is visible on the surface.
It looks to me like the flexible metal inside the wall would be in compliance with code. Also, it looks to me like with the 3 mentioned 4 ga wires I can still use 1" conduit. I kind of like this option, but what type of connector would I need to use to come through 1/2" drywall and attach to the back of the box?
Sorry this is so long winded. I just want to make sure you have a good picture of what I am doing.
Bottom line questions.
Is 1" conduit large enough for 3 conductors of 4 ga THHN? Is this true for EMT and flexible metal? If I bore holes in the studs I would rather stay with 1" as long as it is large enough. Would you guys go up to 1 1/4" even if the 1" is large enough?
What is the best method of transitioning conduit from behind drywall to a surface run so that it is done correct and also looks clean.
Is a 12 foot run of flexible metal conduit inside a wall acceptable? What would be the correct way to attach the flexible metal to the back of my control panel allowing for the thickness of the drywall?
What would be your preference if you were doing this?
Thanks."
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I am wiring in my phase converter. I have a couple of questions about using conduit and would like some advise and opinions.
When the house was built, I had the electrical contractor install a 100 amp sub panel in the garage. It is an oversize 3 car that will serve as my shop and is attached to the house. The panel face is flush with the drywall and the depth of the box is in the wall.
I went to the local electrical supply place and bought a 2011 NEC book, and I think I am tracking on everything OK, but I want everything to be done right the first time so I am seeking some advise.
I have an American Rotary 15 hp RPC. American Rotary says to use 4 ga copper wire for the supply. I am good with that, but it means I will need to run the supply wires through conduit as I can only find 4 ga copper in single stranded wire.
My converter panel will ideally be about 12 feet from the sub panel to get things laid out they way I would like them. Both panels will be mounted on the same wall, a straight run with no corners, windows, doors or anything between them. The garage is complete, so I think it would be very difficult to run EMT conduit through the studs (2x6 BTW).
Here are some questions. What I came up with sizing the conduit came out to 1" EMT. That was 3 wires, THHN 4 ga. A buddy of mine said I need 1 1/4 conduit. I think bigger would be better and I don't mind spending the extra money, but I am thinking 1 1/4 might be a little harder to work with.
How would you guys go about this? This is what I am leaning toward. Should I come out of the sub panel, (behind the drywall) with EMT conduit, come straight down and come out of the wall at the bottom near the floor, 90 degree it and run along the surface of the drywall until I am under the panel, junction box it and then go up into the bottom of the RPC control panel. The panel will be surface mounted of course.
A second option that I kicked around with my buddy is to use flexible metal conduit and bore holes in the studs. Keep everything behind the drywall, come into the control panel from the back so nothing is visible on the surface.
It looks to me like the flexible metal inside the wall would be in compliance with code. Also, it looks to me like with the 3 mentioned 4 ga wires I can still use 1" conduit. I kind of like this option, but what type of connector would I need to use to come through 1/2" drywall and attach to the back of the box?
Sorry this is so long winded. I just want to make sure you have a good picture of what I am doing.
Bottom line questions.
Is 1" conduit large enough for 3 conductors of 4 ga THHN? Is this true for EMT and flexible metal? If I bore holes in the studs I would rather stay with 1" as long as it is large enough. Would you guys go up to 1 1/4" even if the 1" is large enough?
What is the best method of transitioning conduit from behind drywall to a surface run so that it is done correct and also looks clean.
Is a 12 foot run of flexible metal conduit inside a wall acceptable? What would be the correct way to attach the flexible metal to the back of my control panel allowing for the thickness of the drywall?
What would be your preference if you were doing this?
Thanks."