Stepping Up Shop Voltage

More powerful machinery may need higher-voltage power. There's more than one way to obtain that. August 22, 2007

I have been working with wood as a hobby for over 15 years and worked in a custom cabinet shop for a few of those years. I am now in the process of opening a cabinet shop specializing in kitchens and baths. I have yet to find a shop to lease out, but I would like to know what voltage you are using in your shop. What would you recommend? The tools I have now all run on 110V, but I am going to upgrade my table saw and compressor.

Forum Responses
(Cabinetmaking Forum)
From contributor J:
A lot depends on how much growing you will do, so I'll start with the assumption that as you succeed and grow your business, you'll outgrow your first shop. Having said that, the minimum you should look for is a 200 amp single phase service. This will be plenty for a one man shop and adequate for up to a 2 or maybe 3 person shop. After that, you'll probably need more.

If you want to be able to look for industrial machinery, you should consider finding a space with a 3 phase service. 220 volts is fine for now. Mostly any machines under about 10 hp will run on 220v. If you grow bigger and need bigger equipment, you'll start looking for a bigger shop, bigger power, and higher voltages.

Most industrial/commercial areas will have 3 phase, so it just depends on where you're looking. As an example, I have a 2000 sq. ft. shop with a 60 amp 1 phase service and a 100 amp 3 phase service. The 60 amp is too small, but all my machinery is hooked up to the 3 phase panel, so I just squeak by.

From contributor B:
I am a small shop with one employee and have two 220v volt 200 amp 3 phase services and am looking to add a third. I would like 440 but the expense at this point is a little high. The higher your voltage, the smaller wire required to run a machine.

From contributor D:

We have upgraded our electrical twice since opening our shop 2 years ago. As our business grew we needed bigger machines and more power. We now have 2-200amp and 1-400amp 220v single phase services with a 30 hp and a 60 hp phase converter and 2 -30 KVA. One reduces our three phase output to 220 instead of the line 240. The other turns our 240v to 440v for our resaw. Be aware that single phase load is 1.7 times the three phase load when using a phase converter, so single phase panels need to be 1.7 times the desired 3 phase current.

From contributor H:
How does your service step from 220v to 440v? I found only one space for lease in my area, within my budget, that had 440v 3 phase service. The ability to convert 220v into 440v would open a lot of opportunity! Please tell?

Also, most machines I see specify 220v or 440v three phase... "440v requires use of additional equipment." What exactly is that additional equipment?

From contributor D:
My 240volt single phase goes into a rotary phase converter to be made into 3 phase 240. It then goes through a 30 KVA transformer that converts it to 440volt 3 phase. The rotary phase converter cost about $2K and the transformer I bought used for $400. I am in very rural Brown County Indiana where I am only able to get single phase power from REMC. It has worked well, although I pull a great deal more amps at the meter than if I had a 3 phase service. I am told it equals about 1.7 times the amp load than what a 3 phase service would see.

Wikipedia has a good article on transformers and their function. Just Google "electric transformers" and you will find a wealth of info about how this works. It was interesting to find out that a transformer also isolates sensitive electronics like machine controllers from the actual line voltage. The input current actually generates the output voltage by induction. It has been a crash course in industrial electric trying to get our shop converted from hobby or contractor equipment to more substantial industrial equipment. We save a fair amount on our electric rate too because our service is considered residential and not industrial by REMC. Jay at American Rotary Phase Converters has helped us figure out a lot of this as well. You can find them through Google as well.

From the original questioner:
Thanks for all your input. I will be a one man shop for the first while. My two major tools will be table saw and compressor. I will be outsourcing the doors and drawer fronts, so I think 220 should do it for now.