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Discussion Starter · #1 · (Edited)
Prologue:

I am a hobbiest woodworker who is starting to move into more industrial machines (12 in jointer, 17 in bandsaw, etc) and am in need of 240v power to the garage.

My subpanel is full and although I realize that I can make space using tandems, I believe it would be best to place a subpanel in the garage along with dedicated circuits for select pieces of machinery. I checked my 200 amp main service panel (outside) and it has space for another breaker.

I would like to run service wiring under the house through conduit to the garage and attach a subpanel on the back wall, where the wiring for each of the machines would then branch out. These branches would be done using exposed conduit.

My question is:

What would be the best way to do this? I have read contrasting information about the use of MC cable or Romex and various height restrictions for how far they must be off the ground. I have attached a terribly drawn diagram, along with images of my main panel (outdoor) panel and full service panel for help visualizing.

I am located in Middle Tennessee if that matters.
 

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A "Handy Husband"
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You need to determine the load to size the cable. I would run aluminum SER cable from the main panel to the garage. Conduit not required unless it is in a location subject to damage.
 

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Discussion Starter · #3 ·
You need to determine the load to size the cable. I would run aluminum SER cable from the main panel to the garage. Conduit not required unless it is in a location subject to damage.
I was planning on putting a 60 amp subpanel in the garage - although it would never reach that at a given time. Max 30 at any time.
 

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A "Handy Husband"
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With that load I would run 6/3 NM.

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You mentioned conduit. Any reason you are talking about cable?
I always prefer conduit. You can run 1" under the house (PVC) and just pull your THHN wires with a ground. You can easily get the 60 amp you need.
Conduit is neat and rodent proof....something to consider under a house.
I recently installed a panel in a small woodworking shop about 20 feet from the main panel.
I used # 6 (or #8), cannot remember for a 60 amp sub-panel.
If you use conduit, and your needs should increase you can always pull larger wire to satisfy the additional amperage. Just start with a larger conduit if you anticipate that.
 

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Discussion Starter · #9 ·
I'd run SER. Under the home, such as a crawl space may be considered a wet location. NM is not approved for wet locations.
Ok thank you guys for all the responses -

Tallying up materials right now...

60A breaker to put in the main
60 ft of PVC conduit (2 inch??)
Combo connectors, threaded couplings and bushings
100 amp subpanel (GE TM2010CCUBK1)


Trying to decide on type of wire - I think I am going to go with:
- Aluminum 2-2-2-4 SER to go from the main to the subpanel through conduit underneath the house
- 12/3 for the 240v receptacles
14/2 for the 120v receptacles

Is armorclad such as https://www.lowes.com/pd/Southwire-Armorlite-100-ft-12-3-Solid-Aluminum-AC-Cable/3642638 up to code for being exposed? or should I do something else and feed it through conduit??
 

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Ok thank you guys for all the responses -

Tallying up materials right now...

60A breaker to put in the main
60 ft of PVC conduit (2 inch??)
Combo connectors, threaded couplings and bushings
100 amp subpanel (GE TM2010CCUBK1)


Trying to decide on type of wire - I think I am going to go with:
- Aluminum 2-2-2-4 SER to go from the main to the subpanel through conduit underneath the house
- 12/3 for the 240v receptacles
14/2 for the 120v receptacles

Is armorclad such as https://www.lowes.com/pd/Southwire-Armorlite-100-ft-12-3-Solid-Aluminum-AC-Cable/3642638 up to code for being exposed? or should I do something else and feed it through conduit??
Maybe I didn't see it before, but why 12/3 for 240v? 2-wire is what is needed for 240.
 

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A "Handy Husband"
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I would not pull SER into conduit. It is not a violation but it will be a very tough pull. Use individual conductors.

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I agree. If the conduit is continuous from panel to panel install individual conductors . Cheaper and easier to install. Conductors will need to be approved for wet location. Most conductors are. If the designator ends in W such as XXHW it is ok.
 

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Code:
So I would need 12/2 for 240v and what for 120v?
The size is dependent upon the current draw (#12 wire is for 20 amp; #14 is for 15 amp). I use 14/2 for lighting and general purpose outlets (some use 12/2, but I think it's overkill). 12/2 for the 20-a 240-v receptacle.

The difference is that with the 120-v (20 amp) receptacle, the white wire will be used as a neutral. For the 240-v, the white wire will be a Hot.

So, if you want to use all #12, just 12/2 with ground is good for both.
 

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Ok thank you guys for all the responses -


Trying to decide on type of wire - I think I am going to go with:
- Aluminum 2-2-2-4 SER to go from the main to the subpanel through conduit underneath the house
??
No No No.
You are making this much harder than it has to be.
Install 1 1/4" PVC and pull 3 6's and a ground. DO NOT PULL CABLE!!
You said you only needed 60 amp.
Three 6's will be more than adequate.
 

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Sorry if this insults you but some of your questions make me think that perhaps you aren't up to doing this project yourself.
If I am wrong, I apologize. I just don't want to you to make a serious mistake.
 

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Discussion Starter · #17 ·
No No No.
You are making this much harder than it has to be.
Install 1 1/4" PVC and pull 3 6's and a ground. DO NOT PULL CABLE!!
You said you only needed 60 amp.
Three 6's will be more than adequate.
Ok I'm understanding how after looking at the differences between the size of the wire/cable.

Now, it would be much more economical to buy one color in bulk and then label the ends but I'm assuming that it is against code to do so?
 

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Discussion Starter · #20 · (Edited)
If what you mean by "labeling the ends" means placing black tape on the white wire going to the 20 amp 240-v breaker, it is NOT against code, and is probably preferable.
I believe we are on the same page - but just want to make sure.

Instead of buying 100 ft of black, 100 ft of white, 100 ft of green;

can I just buy 300 ft of black 6AWG and label the white/green with the appropriate colored electrical tape?
 
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