Subpanel or new service?

[catldavis]

Hello all, trying to figure out how to power my shop. My house has a 200 amp panel. All of the spaces in the box have breakers except for two. Therefore, I could put a double-pole 100 amp breaker in the panel. However, I have a significant run to the shop, better than 350 ft so I'm concerned what size wire it will take not to have too much drop. Any idea how to size the wire?

My other option is to see if the power company will allow another main from the power pole. The problem with this is the cost to make it happen. Additionally, the power company has a healthy minimum monthly service charge and I'm trying to save my pennies so I can retire and enjoy the shop.

Any suggestions would be greatly appreciated.

 

[wyliesdiesels]

You first need to start with your loads. What loads will you have? How many people working there? Youmay be able to get away with less than 100 A

 

[u2slow]

Wire size can be kept smaller for breaker (or subfeed lug) fitment, and then outside the panel - step up the wire in a splitter box.

 

[catldavis]

You first need to start with your loads. What loads will you have? How many people working there? Youmay be able to get away with less than 100 A

Just me, light use, most everything is 110V.

 

[pattenp]

Light use is vague. The total amps you think you might use at one time is more helpful. With that said I think 2/0-2/0-2/0-1 MHF is probably a good fit for the distance and should handle your needs short of heating and cooling not knowing how big the shop is. The 2/0 aluminum at your distance will handle around 80 amps with allowable voltage drop.

 

[mike93lx]

I wouldn't go through all that work for anything less than 60a and would be targeting something in the 80-100a range. Secondary service only if it was the only option. Part of the issue there is installation cost. They are likely going to charge you if your load sheet doesn't show any real loads.

 

[laser3kw]

I have a subpanel feed from a 60amp breaker 75 feet away, buried, sized to handle 100 amp (if needed in future). I have ample lighting (30 t8 tubes) and various intermittent loads - air compressor, welder, lathe, mill. Have not even come close, in 10 years, to needing more.

 

[catldavis]

I have a subpanel feed from a 60amp breaker 75 feet away, buried, sized to handle 100 amp (if needed in future). I have ample lighting (30 t8 tubes) and various intermittent loads - air compressor, welder, lathe, mill. Have not even come close, in 10 years, to needing more.

Very good info. That's mostly what I will be using - I have a CNC lathe/mill combo, air compressor, welder, car lift, etc. However, can't imagine many will be used at the same time.

 

[mike93lx]

Very good info. That's mostly what I will be using - I have a CNC lathe/mill combo, air compressor, welder, car lift, etc. However, can't imagine many will be used at the same time.

I bet about max would be hvac running, while you are welding/plasma cutting and your compressor kicks on.

60a really should do just about any one man shop. If you were adding an EV charger, it might be worth increasing that, but charging can done after hours in most cases

 

[laser3kw]

I bet about max would be hvac running,

that's uptown money talk'n right there!
seriously, I am accustom to working without in warm months and heating with propane when I'm out there in the winter. Like mentioned, I'm just one guy, and it's unlikely that I would have two high current draw items on at the same time (air compressor and welder)

 

[rancherbill]

Very good info. That's mostly what I will be using - I have a CNC lathe/mill combo, air compressor, welder, car lift, etc. However, can't imagine many will be used at the same time.

You know your equipment, and if 60 is good then that's all you need. The only thing that might change is if you source some used 3 phase machining equipment. Three phase stuff is cheaper at the auctions. Who knows what the amps will be so at this point it might be worth doing the 100.

 

[mike93lx]

You know your equipment, and if 60 is good then that's all you need. The only thing that might change is if you source some used 3 phase machining equipment. Three phase stuff is cheaper at the auctions. Who knows what the amps will be so at this point it might be worth doing the 100.

Most residential services have HP limits, so if that is the case, the demand can only get so high. That limit seems to often be 7.5-10hp

 

[rancherbill]

Most residential services have HP limits, so if that is the case, the demand can only get so high. That limit seems to often be 7.5-10hp

I don't know, I do not truly understand the magic of VFDs and Rotary Phase Converters. I do know people get smoking hot deals on lathes, mills, etc. because most people do not have three phase power.

 

[mike93lx]

I don't know, I do not truly understand the magic of VFDs and Rotary Phase Converters. I do know people get smoking hot deals on lathes, mills, etc. because most people do not have three phase power.

Sure, but that doesn't necessarily mean high draw. You can do a lot of work with a 3hp motor

 

[catldavis]

You know your equipment, and if 60 is good then that's all you need. The only thing that might change is if you source some used 3 phase machining equipment. Three phase stuff is cheaper at the auctions. Who knows what the amps will be so at this point it might be worth doing the 100.

I have another place that has an outside meter can/panel combo (the small house's panel is being used as a sub panel). It's 200 amp service and plenty of space for breakers. If I decide to 3 phase something, I can put a smaller shop there and have plenty power options.

 

[rancherbill]

If I decide to 3 phase something, I can put a smaller shop there and have plenty power options

You can easily turn 240 volt single phase (you have it now) into 3 phase power. You need a VFD (Variable Frequency Drive) or a homemade rotary phase converter. You have tons of power in your panel. The amount of power that you actually use in your house is way less than 200 amp. You probably shouldn't have to go to another building to get enough power you probably have enough already.