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Need input wiring for a MIG & compressor in my attached garage

Need input wiring for a MIG & compressor in my attached garage

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  #1  
Old 09-28-15, 12:05 PM
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Need input wiring for a MIG & compressor in my attached garage

I have attached pictures of my main (200A) and sub-panel (70A breaker in the main). The main shares a wall with the garage and the sub-panel is located in the garage. I haven't opened up the panels yet. I was thinking i could run the new wire from the main into the garage.

The welder is a miller 251.



The air compressor is an Ingersoll Rand SS5l5. I have attached a picture of the label.



What wire would i need for each?




I took the cover off the main panel this morning. Looks like it would be really difficult to pull wire into and up the wall through the provided opening without cutting sheet rock.



My thought right now is to run conduit out the top of the main panel up into the soffit/attic and drop through the wall where i want the outlet on the inside.



Currently planning on using #8-2 NM-b for each with a 30A breaker and hardwired switch for the compressor and and 50A breaker for the welder.

Can i run the conduit through the top of the main panel into the soffit? would i need wet rated wire?

Should i get cut into the sheetrock on the inside and push the wire up the wall?

Trying to keep everything in the walls as much as possible.

Thanks
 
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  #2  
Old 09-28-15, 12:08 PM
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I approved your post due to the amount of pictures in it as a new member. You normally need to have ten posts before posting more than five pictures. It part of the spam reduction system.

Your compressor will need #10 wiring and a 2P30A breaker.
The welder requires #8 wiring on a 2P50 breaker.
#8 for both is also fine.

Going thru the wall is ideal but I see brick in your way and you're dealing with some heavy cable here. You'll have to run individual THHN wires thru the pipe. NM-B can't be in that pipe outside.

Get the proper hub for the top of the main breaker box. This will give you a place to connect your pipe.

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Last edited by PJmax; 09-28-15 at 12:23 PM.
  #3  
Old 09-28-15, 12:25 PM
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Thanks Pete,

Yea I'm trying to do everything right and to code. Code for my area is 2008 NEC. Already talked to the city, did the permit, and am approved for the work. Just don't want to do it and have the inspector tell me i did something wrong. Ive gotten quotes for ~$700 for just the welder circuit. Trying to save a few dollars by taking out the $100-$125/hr labor.

Looks like the hub you have pictured is EMT? Is that the right product to use vs. sch 80 PVC? I was just thinking PVC because thats whats run to the meter and from the meter to the main.
 
  #4  
Old 09-28-15, 01:21 PM
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would i need wet rated wire?
Yes. THWN. If you use continuous conduit all the way or you would use UF cable.
Looks like the hub you have pictured is EMT?
No, it just takes a threaded adapter or threaded conduit. PVC conduit and an adapter would be easiest.
 
  #5  
Old 09-29-15, 10:39 AM
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What am I missing here? Is your indoor breaker panel directly opposite the Main Panel on the other side of the wall?
If it's not, why can't you just pop out one of the 1" knock outs of the Main panel near the bottom and drill a (1 3/8" dia.) hole through the brick wall?
Y0u probably don't own a hammer drill with that big of bit, but you can rent one.
You can mount a small 4 space sub panel on the inside wall and use a 1" threaded steel pipe nipple and lock nuts to connect the inside sub panel and the outside main panel.
This would give you space for (2) 2 pole breakers, one for the compressor and one for the Welder.
I would use (2 runs of) #6 Thwn copper protected by a 60 amp 2 pole breaker mounted in the Main Breaker Panel to feed the new inside "feeder" panel and 1 run of Green (or bare) #10 copper for the grounding/bonding conductor.
I would protect the Mig Welder with a 40 amp 2 pole breaker and the Air Compressor with a 30 amp 2 pole breaker.
Both of these breakers would be inside the garage in the new 4 space "feeder" panel.

I would also close the opening around the conductors as they travel through the 1" conduit with "fire stop" putty.

When you drill through the brick wall, take your time and make sure there's nothing hidden and in the way....Like a gas or electrical line.

Just my opinion.
 
  #6  
Old 09-29-15, 10:43 AM
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The OP doesn't want any wiring exposed inside the garage.
 
  #7  
Old 09-29-15, 11:00 AM
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PJmax,
Correct, i would like to not have exposed conduit inside my garage.

hillbilly ace,
The current sub panel is not back to back with the main. they are on opposite sides of the garage.

The only issue with running it back to back with a new sub panel that i can see is routing the wiring into the attic. i wouldn't be able to unless i mounted the sub panel to the side of the main. Trying to do as little drywall work as possible.

I know where all the electric lines are on that wall. My house was a new build when i bought it so i went to a house that was the same model as mine and took photos of all the wiring before the drywall was put up.

From your suggestion it sounds like i might be able to put an LB to the right of the main and run it into the a sub panel on the inside. That would provide the offset needed to run the required wiring vertically into the attic.
 
  #8  
Old 09-29-15, 11:14 AM
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i went to a house that was the same model as mine and took photos of all the wiring before the drywall was put up
There is no plan just general directions on what is needed. Wiring is installed at the discretion of the electrician. No two electricians will do it exactly the same and throw in helpers and apprentices and guys hired from the street corner the other house may not be representative of yours.
 
  #9  
Old 09-29-15, 11:18 AM
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Just so I understand correctly.
The Garage where the welder and air compressor are to be located is not directly on the other side of the wall from the Meter Main?

If the garage is directly on the opposite side of the wall where the Meter Main is mounted, the only thing you would see with my first suggestion is a small breaker panel mounted on the wall inside your garage with (2) 2 pole breakers in it. No conduit visible.

Are you wanting to hard wire the compressor and welder?
I had it in my mind that you wanted to use flexible SJ Cord to plug them in
 
  #10  
Old 09-29-15, 11:43 AM
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ray2047,
Thanks, good to know.


Here is a floor plan with the locations of the welder and compressor. I want to hardwire the compressor to a switch box as it has a 5hp motor on it. The welder will be a 6-50R plug. I guess i could put the welder outlet behind the main as well since the welder is on wheels, but the compressor is not moving.



Here is a picture of the garage. I wish it was still this empty, filled it up after i put down the epoxy.


 
  #11  
Old 09-29-15, 12:38 PM
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You could trench along the foundation and run the pipe underground to the back of the garage, then poke through the wall in that location. Ultimately, I'd probably prefer to cut out a piece of drywall behind the panel and fish up to the attic. You could pretty easily refinish it or put in a removable panel and paint to match.
 
  #12  
Old 09-29-15, 03:55 PM
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The only thing I'll add is that you may have to upgrade to a 40 amp or possibly even a 50 amp breaker for the 5 HP compressor motor to get the motor started. #10 wire for the motor is fine.
 
  #13  
Old 09-30-15, 11:16 AM
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Yea, looks like i'll probably cut out a hole behind the panel and run a pvc nipple to the main. Seems to be the best option. I'll probably just move the welder outlet to right there (already have an 8-2 extension) and run the compressor up into the attic.
 
  #14  
Old 12-07-15, 03:43 PM
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So i finally have some time off and am trying to knock this out. I was going to run straight through the wall to the interior side but looks like i have some sort of metal sheet against the board behind the brick. Could that be some sort of flashing? Not sure i'll be able to punch straight through with that sheet being there. It doesn't look like its on the entire exterior, just behind the main where the wires go vertical to the attic.
 
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