ToddW
Well-known member
I've been talking to electricians for this part of the project as I believe my current setup is a very old way of doing things. However, I've gotten two answers and want to get opinions of others here 
Currently the (detached) shop is running on 2 sets of 12ga bonded together at the sub-panel inside the shop/house... and by sub-panel, it's barely that... only fits iirc 5 circuits and well, uses two sets of wires bonded which I think now is only allowed at a much larger wire size? (House/Shop are old).
Goals:
- New Sub-Panel that will handle many circuits (120v & 240v)
- 200 AMP load capacity
- Distance from Meter / connect-through (120' or less, may be closer to 100' I need to re-measure)
- Trench & Run 2" Conduit
I won't be doing this install / hookup but I will trench and run the conduit.
I've talked to a couple and some are saying 2/0 and other are saying 3/0.
Questions:
I know I'm going to get asked why 200AMP to the shop so I'll answer it ahead of time
Expandability
and desire to only do things once. Our house actually uses VERY little electricity (all gas, no central heat/air) so without upgrading to 400 AMP at the house I could theoretically pull 150 AMP @ 240V with no affect to the house. The shop also has an office upstairs which will have approx. 60U of (computer) server space filled to capacity, not running 24/7 but at 240V that could draw A LOT of power depending on business needs. In addition my 'ultimate' goal for the shop is to be able to run these at once:
- Office Upstairs w/Servers (30A 240v)
- 7.5 - 10HP Compressor motor (40-50A)
- Hypertherm Powermax 85 Plasma Cutter (60A)
- Lights/Chargers/Fans
- 225 TIG Welder (50A but can use more on arc)
I sold my CNC Plasma setup a while ago, but I'll be setting up for it again in the next year or so, and want it to be able to run while I'm welding / using the shop for other purposes. The likelihood of me running all of the above at 100% is unlikely, but running Plasma at 100% on CNC is very likely as well as compressor running 100% it's the welders/servers/lights/fans that likely won't be at 100% and will keep the load around 150A during 'demand' periods.
I'm leaning toward going with the 3/0 wire for the above safety factor, and minimal increase in cost increase overall for entire electrical project.
And, to state again I won't be doing this service hookup trying to learn from those who have so I can make the best choices

Currently the (detached) shop is running on 2 sets of 12ga bonded together at the sub-panel inside the shop/house... and by sub-panel, it's barely that... only fits iirc 5 circuits and well, uses two sets of wires bonded which I think now is only allowed at a much larger wire size? (House/Shop are old).
Goals:
- New Sub-Panel that will handle many circuits (120v & 240v)
- 200 AMP load capacity
- Distance from Meter / connect-through (120' or less, may be closer to 100' I need to re-measure)
- Trench & Run 2" Conduit
I won't be doing this install / hookup but I will trench and run the conduit.
I've talked to a couple and some are saying 2/0 and other are saying 3/0.
Questions:
- 2/0 Copper or 3/0 Copper? ($200 more to buy 500ft roll of 3/0 vs 2/0. Likely marginal difference if I go to an electrical supply place and buy <500ft but closer to 250'. HomeDepot/Lowes better off going with the 500' roll.) Also, I believe It needs to be THWN-2, right?
- SCH80 Conduit or Metal?
- Which 240v fused disconnect would you use? Do I need one at the house + shop for this or only at the house?
- Suggested Sub-Panel in Shop? I was looking at the: Square D HomeLine part# 97723
I noticed there are 42 space, and 54 space for a little more money, and some other 'methods' of attachment/wire. I'd like to do this once, and right. If that means spending 2x on the box or buying non-home owner and going more commercial please show me the path
I know I'm going to get asked why 200AMP to the shop so I'll answer it ahead of time

Expandability
and desire to only do things once. Our house actually uses VERY little electricity (all gas, no central heat/air) so without upgrading to 400 AMP at the house I could theoretically pull 150 AMP @ 240V with no affect to the house. The shop also has an office upstairs which will have approx. 60U of (computer) server space filled to capacity, not running 24/7 but at 240V that could draw A LOT of power depending on business needs. In addition my 'ultimate' goal for the shop is to be able to run these at once:- Office Upstairs w/Servers (30A 240v)
- 7.5 - 10HP Compressor motor (40-50A)
- Hypertherm Powermax 85 Plasma Cutter (60A)
- Lights/Chargers/Fans
- 225 TIG Welder (50A but can use more on arc)
I sold my CNC Plasma setup a while ago, but I'll be setting up for it again in the next year or so, and want it to be able to run while I'm welding / using the shop for other purposes. The likelihood of me running all of the above at 100% is unlikely, but running Plasma at 100% on CNC is very likely as well as compressor running 100% it's the welders/servers/lights/fans that likely won't be at 100% and will keep the load around 150A during 'demand' periods.
I'm leaning toward going with the 3/0 wire for the above safety factor, and minimal increase in cost increase overall for entire electrical project.
And, to state again I won't be doing this service hookup trying to learn from those who have so I can make the best choices