Hey everyone. I had a question regarding wire size for my shop. My house has 200amp service and the shop will have 150amp service. The distance underground is 230ft. Will be running copper. I’ve talked to some supply houses and they say that they aren’t electrician so they can’t recommend wire size. What size have you run in similar situations to avoid a lot of voltage drop? Thank you
Wire size for shop
- Thread starter chris743x
- Start date
luvtheheat
Well-known member
Voltage Drop Calculator | Southwire
www.southwire.com
rd65
Well-known member
Are you sure you will be running copper? That will be an expensive run if done in copper. My run was about the same distance but only 100 amp, copper was twice what aluminum was.
mike93lx
ALLIANCE MEMBER
Don't use the southwire calc. It is wrong.
Why copper and why 150a? Thats a huge amount of money for wire and a huge amount of power for most shops. Aluminum is perfectly safe, just need to go a little bigger
That said, 2/0 will be right on the edge of 3% voltage drop.
What are you running that you need so much power out there?
Why copper and why 150a? Thats a huge amount of money for wire and a huge amount of power for most shops. Aluminum is perfectly safe, just need to go a little bigger
That said, 2/0 will be right on the edge of 3% voltage drop.
What are you running that you need so much power out there?
luvtheheat
Well-known member
What aspect is incorrect? It provided the same results as the site you recommended.
Not arguing, but am curious.
It’s what I had growing up in my dads barn and was in the mind set of just doing 150A to be good for anything that may come up in the future. Doing a car lift and will have basic auto wrenching going on. I’ll look into aluminum as well now. Thanks!
mike93lx
ALLIANCE MEMBER
Maybe they fixed it, but they were wrong for a long time
dcg9381
Well-known member
It's really rare to need 150A for a shop unless you're commercial. MHF is the standard GJ answer, but I didn't look up the drop on 230 ft.
I have 320A service. My 200A main to the house is aluminum, the shop is 90A MHF - also aluminum. It's split at the service entrance.
Copper absolutely has it's place, but usually in cases where wire size is a factor. Is the shop wired from the house?
I have 320A service. My 200A main to the house is aluminum, the shop is 90A MHF - also aluminum. It's split at the service entrance.
Copper absolutely has it's place, but usually in cases where wire size is a factor. Is the shop wired from the house?
90a mobile home feeder is the go to size for a one man basic shop around these parts.
pattenp
Well-known member
The best thing to do is a load calculation of your anticipated use. You may find 100A is plenty. And totally agree with others on aluminum.
mike93lx
ALLIANCE MEMBER
Sure, lots of capacity, but there is basically no way for a single person to use that much juice.
I'd cut it way back and aace some money
wyliesdiesels
Well-known member
total waste of money
unless you will have multiple people working at the same time, you wont come close to even using 90a, much less 150a
NakeDiesel
Well-known member
Hum, 5 ton heat pump, 3 strings of flourescent lights, ceiling fans, shop stereo, large air compressor, plasma torch or my welders, air chiller, couple of trickle chargers, window ac in my honey room, etc.. I have 200 amp service to my shop. Believe I ran 4/0 aluminum, but it's been many moons ago. Add my son working on his projects and it adds more power consumption.
In most residential scenarios feeding anything over 60 amps with copper is throwing away money. Go with the 150 amp feeder if you really want, but at least save yourself some bucks by using aluminum. The money you save will go along way towards your electrical rough in and finishing costs.
Thanks for all the responses. I measured it today to get an exact number and its gonna be 275 feet from house to barn. I will be going with Aluminum now for sure. Now to find a place that has 4/0 in stock.. Still gonna put in the 150amp service as well.
mike93lx
ALLIANCE MEMBER
Wireandcableyourway.com
Mobile home feeder come bundled allows for direct burial and can go inside the structures, as long as it is in conduit. Xhhw is a hair cheaper, but comes separately, and requires conduit (also fine indoors). Some/most URD cant go inside, regardless of conduit.
Make sure you run a 4 wire feeder
Mobile home feeder come bundled allows for direct burial and can go inside the structures, as long as it is in conduit. Xhhw is a hair cheaper, but comes separately, and requires conduit (also fine indoors). Some/most URD cant go inside, regardless of conduit.
Make sure you run a 4 wire feeder
The breaker is NOT 4 pole, it is a 2 pole breaker that is 4 poles wide, big difference.
mike93lx
ALLIANCE MEMBER
You still need 4/0. If you drop back to 90, you can run 2/0.
It would save you a grand in wire, plus something on all the pvc and fittings
It would save you a grand in wire, plus something on all the pvc and fittings
we need a bat signal for the 90a MHF wire is good enough for 99% of shops.
then another one for wellllll i think 200a cause I feel like it needs it.
mike93lx
ALLIANCE MEMBER
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purediesel
Well-known member
Is there a thing as too much power?? Wouldn't you kick yourself in the **** if you outgrew your power supply someday?? Some things to think about. I called my power company when I ran the power out to my shop and they were more than happy to come out to my house and talk everything over and tell me exactly what I needed to purchase.
mike93lx
ALLIANCE MEMBER
Why didn't you build a bigger shop? Get a bigger house? Buy a bigger truck? Might regret not doing it someday right?
purediesel
Well-known member
Sure..
wyliesdiesels
Well-known member
Except in this case, #2 al is not large enough for the OPs distance
sparky 1971
Well-known member
Without running the numbers, I bet 2/0 would be ok with a 125 amp breaker. I haven't laid on eyes on it yet, but the supply house I use has a 2/0 MHF. It's $6.06 per foot.
Thanks for the response. When I input the numbers on a wire size calculator, it’s still saying 4/0AL. My wallet would love if 2/0 would be sufficient for that distance.
mike93lx
ALLIANCE MEMBER
Practically, it is plenty as you almost certainly will never draw 125. If you really will, then the voltage drop calc you did is valid
Yeah, I don’t ever see my self pushing that limit. Biggest one time hit I have now is a 2 post car lift which requires 30A. I might look into 2/0 then. Thank you
wyliesdiesels
Well-known member
2/0 will be fine
mike93lx
ALLIANCE MEMBER
Just going to ask...are you stuck on 125a because you want a bigger (physical size) panel?
If so, that end doesnt matter. You can put a 42 space, 200a panel out there with any size wire you want. The breaker in the panel that feeds it determines capacity.
IMO, run 2/0 and use a 90a breaker. Then put a big 42 space panel out in the shop. It will be plenty
sparky 1971
Well-known member
You can feed that with any sized circuit you want to, up to 150 amp. The main breaker in that panel is going to be nothing more than a disconnect. Was that panel available on the shelf somewhere? I only see 100 and 200 amp main breaker panels, and it's been that way for years.Here’s what I have already because the initial plan was 150A service in the shop. Would I still be fine with either a 90,100 or 125a breaker supplying this 150A panel. Thank you for of your knowledge!
mike93lx
ALLIANCE MEMBER
Was there something unclear in my post right above yours?Here’s what I have already because the initial plan was 150A service in the shop. Would I still be fine with either a 90,100 or 125a breaker supplying this 150A panel. Thank you for of your knowledge!
sparky 1971
Well-known member
probably
mike93lx
ALLIANCE MEMBER
Got it, thanks for clarifying!