What Wire size and Type

[tman74]

I built an 18' x 30' shop that will be a hobby wood shop, welding shop, mechanic shop and man cave. I know, should have went bigger... Wife said no... I have/will have all the usual wood tools, tablesaw, jointer, planer, miter box, band saws, drill press, shaper, ect. I have a dust collection system installed under the slab and will add a 3-4 HP dust collector. I have a 60 gal compressor, a few smaller welders and want a plasma cutter. The future AC is an older unit that requires a 40 amp and 20 amp breaker. It is spray foamed and will have tin on the interior.

There is 2" conduit stubbed in to the building and it is 54' from the 200 amp meter/panel to stub plus the distance from underground to the panels, so 65' total run.

I plan on installing a 100 amp sub panel. I am thinking that 1/0 Aluminum wire is the best cost effective wire. However, talking to a few folks, aluminum wire is the worst thing in the world. I have researched creep on the lugs and it sounds like that was an issue with older wire and is really not an issue these days. Copper would be great but it is more expensive.

Your thoughts?

 

[marinusdees]

My 27 year old 40' x 40' was wired (by a licensed electrician, in a trade of services). I asked for copper, but he talked me into direct burial Al. I was reluctant. I've never had a problem. I've never monkeyed with the connections. I have a 5 horse air compressor and half a dozen welders, largest being a Panasonic 250 amp mig. I'm now 80 years old, so I don't need another 27 years. I need a new body, and maybe a brain to operate it. Just my experience. I'm sure smarter people than I will criticize, but, ask me if I care??

PS It's about a 125 foot run, maybe a little more.

 

[wyliesdiesels]

I built an 18' x 30' shop that will be a hobby wood shop, welding shop, mechanic shop and man cave. I know, should have went bigger... Wife said no... I have/will have all the usual wood tools, tablesaw, jointer, planer, miter box, band saws, drill press, shaper, ect. I have a dust collection system installed under the slab and will add a 3-4 HP dust collector. I have a 60 gal compressor, a few smaller welders and want a plasma cutter. The future AC is an older unit that requires a 40 amp and 20 amp breaker. It is spray foamed and will have tin on the interior.

There is 2" conduit stubbed in to the building and it is 54' from the 200 amp meter/panel to stub plus the distance from underground to the panels, so 65' total run.

I plan on installing a 100 amp sub panel. I am thinking that 1/0 Aluminum wire is the best cost effective wire. However, talking to a few folks, aluminum wire is the worst thing in the world. I have researched creep on the lugs and it sounds like that was an issue with older wire and is really not an issue these days. Copper would be great but it is more expensive.

Your thoughts?

The biggest question is will this be a one man shop?

If so then #2 al MHF will get you by just fine with a 90a breaker.

Make sure subpanel has isolated neutral bus and you will need 2 ground rods. You will probably need to purchase a ground bar kit as well. Make sure its listed and labeled for your particular panel.

Aluminum wire is no worse than copper when installed properly.

If the lugs are torqued to spec there should be no issues.

If the DC is over 3HP it will need to be hardwired.

What is the HP rating on the motor nameplate of the 60gal compressor?

My 27 year old 40' x 40' was wired (by a licensed electrician, in a trade of services). I asked for copper, but he talked me into direct burial Al. I was reluctant. I've never had a problem. I've never monkeyed with the connections. I have a 5 horse air compressor and half a dozen welders, largest being a Panasonic 250 amp mig. I'm now 80 years old, so I don't need another 27 years. I need a new body, and maybe a brain to operate it. Just my experience. I'm sure smarter people than I will criticize, but, ask me if I care??

PS It's about a 125 foot run, maybe a little more.

Nothing wrong with aluminum wires of today but direct burial is a bad idea.

 

[Bert_]

but direct burial is a bad idea.

I don't really agree with that. I fix a few underground wires each year, mostly direct burial.

Most of the time the failure is because someone HIT the wire. I have had to fix a few that were in conduit the whole way, MUCH more time consuming than fixing direct burial.

I do install conduit if the soil is very rocky or if there will be concrete poured over top of the wire.

 

[sberry]

I got 1000s of feet direct for decades, never had a problem.

 

[marinusdees]

I got 1000s of feet direct for decades, never had a problem.

Thanks.

 

[marinusdees]

The biggest question is will this be a one man shop?

If so then #2 al MHF will get you by just fine with a 90a breaker.

Make sure subpanel has isolated neutral bus and you will need 2 ground rods. You will probably need to purchase a ground bar kit as well. Make sure its listed and labeled for your particular panel.

Aluminum wire is no worse than copper when installed properly.

If the lugs are torqued to spec there should be no issues.

If the DC is over 3HP it will need to be hardwired.

What is the HP rating on the motor nameplate of the 60gal compressor?



Nothing wrong with aluminum wires of today but direct burial is a bad idea.

As I said, ask me if I care.

 

[wyliesdiesels]

As I said, ask me if I care.

Huh?

You dont care about anything Ive said?

Then why come on a forum for help?

 

[marinusdees]

Huh?

You dont care about anything Ive said?

Then why come on a forum for help?

I didn't ask for help.

 

[wyliesdiesels]

I didn't ask for help.

I confused you for the OP...

 

[tman74]

Thanks for the feed back! Aluminum is a go!
Yes it is a one man shop.
@wyliesdiesels, I am not sure about the 2 additional ground rods. I am located in the pan handle of Florida in very, very sandy ground. I worked part time at a camp ground and had a ton of lightning strikes. Hired a pro, and he said we had too many ground rods and that they created different grounding potential, and caused additional strikes. We disconnected a bunch of rods and almost zero strikes.

If i run a 1/0 neutral and a #2 ground, won't that be a sufficient ground?

If the DC is over 3HP it will need to be hardwired. It will be.

What is the HP rating on the motor nameplate of the 60gal compressor? It is a Cambell Housfeld, with a SPL rating. Peak 6 HP maybe.

 

[pattenp]

If you are installing a 100A subpanel and feeding with it with a 100A breaker from the main panel then all you need is #1 Al, not #1/0 Al. The wire sizes will be 1-1-1-6. Use aluminum XHHW-2 type wire if using conduit. If doing direct bury use USE-2/RHH/RHW-2.