primetime wrote:

On Jul 27, 9:20 am, Jordan wrote:
I'm getting a workshop built, and can make a choice to have 3 phase
power connected.
I'd like to buy some ex-factory machinery.
Q: Is it worth the expense? Or, with electronic solutions to running 3
ph. machines from single phase power, is it not worthwhile?

You definately want 3 phase. Probably 220v. I wouldn't go with the
440v even though a lot of industrial equipment uses this. 220 is fine
for most uses such as for welders and compressors.

480/277V service is great for really big shops, but is to be avoided if
you don't really have the need for it since the distribution panels and
switchgear are significantly more expensive than the 120/240V single
phase or 120/208V three phase versions.

Plus you can run
seperate 120v off each leg and get a larger load off the main line.

Only if you get "Y" service which is 120/208V, not 220V. "Wild leg"
Delta service will give you 240V on your three phase and 120V from only
two of the three phase legs with the third leg being well above 120V
relative to the neutral.

220v welders provide a much longer duty cycle and you can get a bigger
air compressor also.

Yes, but 220V is available from single phase service as well. Three
phase service will let you move up to the "next level" of welders and
compressors like 500A+ welders and 10 HP+ compressors.

The cost will be more because of the extra wiring and use of bigger
wire but you will be glad as time goes by and you need more
outlets.....and you will.
Good luck

Three phase installations will use *smaller* wire than the equivalent
single phase installation since a given load is distributed across 3 hot
leads vs. 2 hot leads. Total wire used is of course more due to that
third wire.

Pete C.