Good morning, I’m at the phase where electric is ready for my 24x30 detached garage. It’s 130’ from my main. Some say use copper other’s aluminum. Is there a right or wrong? The price for copper is insane. I’m guessing I’ll go with a 100amp sub panel? I will be doing a 4 post lift compressor and nothing much else crazy back there. 12 4’ LED lights. Also regarding aluminum vs copper what wire gauge etc… is recommended. Should I do direct burial or run some conduit?
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Recommendations for 24x30 detached
- Thread starter bski224
- Start date
Innovate1
Well-known member
Go Aluminum unless you just have some extra money you don't know what to do with. #2 aluminum is good for 90A which is what a lot of people do. That gives 3% voltage drop for that distance which is fine. 90A breaker feeding it. Use a 100A panel (main breaker is just a switch in this case so anything 90 or greater is fine). I did conduit and XHHW wire but you could do MHF without conduit in the ground. Must still be in conduit above ground and inside. For what you are planning 60A is probably plenty and would let you drop size to #4 but it only looks to save about $25 so I would stick with #2. If you go with MHF you have more limited choices for size. With XHHW you could do 2-2-4-6. Many here get cable from wireandcableyourway.com.
I line the 100A panel and wiring for that capacity to future proof the shop. Maybe a welder one day, for example. 4 post lift uses relatively little power and compressors aren’t that bad for the typical 60 gallon. LED lights might be 40-50 watts for the typical 4000-5000 lumen 4’ model. You can run 30 of those on one 14 gauge 15 amp circuit.
I chose the 220V motor for my Bendpak HD9, but this size 4 post is also usually available with 110V motors that work fine. I’d have to look at the specs to see the draw, but the recommended breaker is probably conservative. My Campbell Hausfield 60 gallon 220V compressor might actually need the 30A breaker, at least on start up. I don’t run it for long, though that will occasionally change once I get my blast cabinet set up.
As for AL vs CU, I have always bought copper. But I have not done a 130’ run. More like half that and smaller wire for 50 or 60A. I don’t think this is a case where you would be saving $1000 but have not priced the wire. If it is a few hundred difference or less, I would go copper.
I chose the 220V motor for my Bendpak HD9, but this size 4 post is also usually available with 110V motors that work fine. I’d have to look at the specs to see the draw, but the recommended breaker is probably conservative. My Campbell Hausfield 60 gallon 220V compressor might actually need the 30A breaker, at least on start up. I don’t run it for long, though that will occasionally change once I get my blast cabinet set up.
As for AL vs CU, I have always bought copper. But I have not done a 130’ run. More like half that and smaller wire for 50 or 60A. I don’t think this is a case where you would be saving $1000 but have not priced the wire. If it is a few hundred difference or less, I would go copper.
Chuckster in NJ
Well-known member
I am not a fan of aluminum wire but if I was on a budget I would use it on an underground feeder to a detached building. Nowadays electrical contractors need to be competitive and have no problem using aluminum wire, so there are is no reason NOT to use it as long as the terminations are done properly.
BTW! "IF" this was my building I would use copper wire pulled in PVC conduit because I am a "old guy" who is set in his ways.
BTW! "IF" this was my building I would use copper wire pulled in PVC conduit because I am a "old guy" who is set in his ways.
Innovate1
Well-known member
Did a rough price on wireandcableyourway.com for 150 ft to allow a bit on the ends.
MHF 2-2-4-6 $292.50
Copper XHHW 3-3-4-8 $913.50
I didn't know what copper was direct burial so just used XHHW. Price of aluminum MHF and equivalent strands of XHHW was pretty equal in price so this should give a rough idea. Of course the XHHW needs conduit and the MHF doesn't. There may be a more close comparison but I think the $600 price difference should be a good estimate for just the conductors (not conduit if needed/used).
MHF 2-2-4-6 $292.50
Copper XHHW 3-3-4-8 $913.50
I didn't know what copper was direct burial so just used XHHW. Price of aluminum MHF and equivalent strands of XHHW was pretty equal in price so this should give a rough idea. Of course the XHHW needs conduit and the MHF doesn't. There may be a more close comparison but I think the $600 price difference should be a good estimate for just the conductors (not conduit if needed/used).
Last edited:
Thank you all for this input!!! Love this site. Thanks again!!!Did a rough price on wireandcableyourway.com for 150 ft to allow a bit on the ends.
MHF 2-2-4-6 $292.50
Copper XHHW 3-3-4-8 $913.50
I didn't know what copper was direct burial so just used XHHW. Price of aluminum MHF and equivalent strands of XHHW was pretty equal in price so this should give a rough idea. Of course the XHHW needs conduit and the MHF doesn't. There may be a more close comparison but I think the $600 price difference should be a good estimate.
wyliesdiesels
Well-known member
#2 AL MHF is your best bang for you buck here. 90a breaker in main, 100a breaker can be in the subpanel. dont forget isolated neutral bar (will most likely have to add ground bars) and 2 ground rods....