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Adding a sub panel in the garage

alex3610

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May 18, 2011
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60
Location
Midlothian, VA
Some background:

I have an attached 2 car garage & house that were built in 1986. There is a single circuit with outlets in the garage currently that is 15amps/14 gauge wire. Electrical service enters the house at the opposite end of the house from the garage and I have a pair of panels in the mudroom both with 150 amp main breakers.

The 15 amp breakers constantly trip when I run my air compressor and are generally inadequate. I also have a 110v mig welder I recently acquired that will surely be an issue as well. Eventually, I will also be adding another welder that will need 220 (AHP Alpha 200x Tig welder).

Originally I was just going to run a new 20 amp circuit to the garage, but when I started thinking about 220 needs down the road I started thinking that it would probably make more sense to just run a sub panel in the garage and then I can expand from there as needed.

So, I would like to eventually have the following in the garage:
  • 20 amp 110v circuit
  • 220v circuit sufficient to run ~200amp output welder (30amps?)
  • Perhaps one day a second 220v circuit for a better air comrpessor when my current one eventually dies. I won't be running the compressor and the welder at the same time.
  • 1 additional 110v circuit that would go from the garage out to a storage shed for a pair of lights and maybe one or two outlets. Probably make it 20 amps to be safe.

Can this be done? If so, what size breaker do I start with in my main panel box? Wire size and type? Approximately a 60 foot run, through a crawl space. I'm pretty comfortable working around electricity and have a general understanding of how things work. But please feel free to tell me if you think I'm in over my head!

Thanks in advance.
 
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Stuff

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Aug 31, 2013
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572
60 Amp is the sweet spot that should handle what you are asking for. Use 6 AWG Cu NM or 4 AWG Al SER.
 

pattenp

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Jun 4, 2008
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Virginia - USA
Hey neighbor, I'm in Chester. Sounds like you can run #4 AL SER cable and install a small 100 amp panel and feed it with 60 amps and be in good shape.
 
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alex3610

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May 18, 2011
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Location
Midlothian, VA
Hey neighbor, I'm in Chester. Sounds like you can run #4 AL SER cable and install a small 100 amp panel and feed it with 60 amps and be in good shape.

Howdy!

So just looking online it appears the aluminum wire is almost half the cost of 6/3 copper. Is there any reason to go with one over the other aside from cost? I don't know if it will make any appreciable difference but I think the most difficult part of this project is going to be fishing wire from the panel in the house down into the crawl space and not resorting to tearing open the wall. Would the smaller diameter of the copper make that a little easier or am I over thinking this?

Does this look like the right kind of panel for the garage?

https://www.homedepot.com/p/Square-D-Homeline-100-Amp-6-Space-12-Circuit-Indoor-Flush-Mount-Main-Lug-Load-Center-with-Cover-No-Door-HOM612L100FCP/100149777

Also, wyliesdiesels made a statement about conduit. Do I need to run this wire through conduit or is it OK just secured along the main beam under the house as is? Thanks for all the help guys!
 

pattenp

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SER is run the same as NM-b (Romex), no conduit is needed except where the wire may be subject to damage then conduit can be used as a sleeve. The panel you linked is fine but sometimes it can be a benefit to have the same brand and model subpanel as the main panel. Is your main panel a Square D Homeline? The reason to use aluminum over copper is only cost. Under the house the cable can be stapled along the bottoms of the joist.
 
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alex3610

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May 18, 2011
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Midlothian, VA
SER is run the same as NM-b (Romex), no conduit is needed except where the wire may be subject to damage then conduit can be used as a sleeve. The panel you linked is fine but sometimes it can be a benefit to have the same brand and model subpanel as the main panel. Is your main panel a Square D Homeline? The reason to use aluminum over copper is only cost. Under the house the cable can be stapled along the bottoms of the joist.

I'll have to double check when I get home tonight but I believe the main panel is Crouse-Hinds.
 

Crazyjake8493

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Sep 26, 2014
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Upstate NY
4-4-4-6 aluminum SER would work, but if there isn't a supply house nearby, you'll likely have an easier time finding 2-2-2-4 SER at Home Depot or Lowes.

I prefer a 100A 20-space main breaker panel for a garage. I went with SqD Homeline since my main panel was Homeline. They're not that expensive ($65 here) and they come with three 20-amp single pole breakers, and two 30-amp double pole breakers, which sounds like what you'd need to get started anyway.

The AHP Alphatig is a great welder for the price. I have the 2015 model and it's been through a lot of welding, both TIG and stick, and no issues. I usually run it on a 240V 30 amp circuit, but I've used it on 120v 20 amp circuits plenty of times without an issue, even up to 150A TIG welding.
 

sberry

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4-4-4-6 aluminum SER would work, but if there isn't a supply house nearby, you'll likely have an easier time finding 2-2-2-4 SER at Home Depot or Lowes.

I prefer a 100A 20-space main breaker panel for a garage. I went with SqD Homeline since my main panel was Homeline. They're not that expensive ($65 here) and they come with three 20-amp single pole breakers, and two 30-amp double pole breakers, which sounds like what you'd need to get started anyway.

Yes, those are a deal. I agree, a 6 doesn't leave a lot of room. I was trying to see how the 8 from Hom was listd and priced and didn't really see the right model at the right price. That 100 for 65 and some breakers is a great buy, just about get a guy started on a project like the OP has. In a garage it is so easy to run single or dedicated circuits we do it.
 
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alex3610

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May 18, 2011
Messages
60
Location
Midlothian, VA
That panel does look like a great deal.

One last question for now. My current panels are set into an interior finished wall. I can fish wires into blank spaces in the bottom of the panel, but once I pull them back in there is no way to get a wire clamp / romex connector (please excuse my lack of electrical terminology) underneath the panel. Is there something I can buy that just pushes in from the top to protect the wire from chafing where it enters the box?
 

Bert_

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Dec 24, 2016
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NW Iowa
Use a two piece NM clamp and install it from the inside. Remove screws and split in half to insert and reinstall screws.

https://www.homedepot.com/p/Halex-1...Piece-Clamp-Connectors-2-Pack-26515/100202798

Also push-in button clamps are available.

https://www.amazon.com/dp/B00422M1X6/?tag=atomicindus08-20


*

That's a nice option. I've also used a standard clamp before. Install it on the cable before you fish it into the wall. Once you get it into the panel you can put the locknut on and connect the rest as normal.
 
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