AFAIK, there is no residential code requirement to put 240V devices on dedicated cc'ts unless required by the manufacturer. I do know that in the shops areas where I teach that 240V devices are on separate cc'ts because they can be and are operated concurrently. I looked in the CEC and couldn't find anything in the residential code regarding 240V and dedicated cc'ts for a workshop. Unless it's code specific, the inspector should be able to give you a code reference why you can't do what you suggest. If there is no code requirement then politely explain your rationale and hopefully he'll OK it.

Thanks! I talked to a friend who is a licensed electrician here in TN, and he could think of no reason a dedicated circuit would be required either. I guess I will find out when the inspector comes.

the limiting factor for how many receptacles on one 20amp line circuits is LOAD / CODE / SAFETY

here 6 general purpose receptacles make one 20amp circuit
and that should NOT have a continous load above 80% max

? a string of 20 amp 220volt receptacles . .curious . .is all of your equipment on hand? and rated at the voltage / current combo?

when you ran a realistic load test on the existing main panel for your home ( with the home having nearly everything turned on ) . .what were your total amperage loads on the mains?
were they anywhere in the neighborhood of the service is that is served to your home ?

you would start there before merely adding a room full of new loads . . .typicaly this is where you'll get an overload situation and a lot of nuisnace tripping

EXAMPLE: had an client decide NOT to get GREAT free advice BEFORE he had bonehead GC put in POOL / SPA /ELECTRIC BBQ / OUT SIDE LIGHTS ETC

called me afterward to hook it all up . .I was flabberghasted that anyone would let a GC conman talk a fella into such stupidity

energizing all his new and uncalculated LOADS..included removal of his current PANEL.and replacement with one that could handle all of the TOTAL CALCULATED AND REALISTIC LOADS . .and the POCO running higher amperage service to the home
accomplish the following:
* Realistic amp clamp readings of CURRENT home
loads ..remebering to turn on just about
everything in the house..get the frig door open
..run the AC..washer /dryer . .whole she-bang
* calculation of all new proposed loads AND the
calculated in-rush and the Code requirement for
INCREASED conductor/breaker sizing for the motors
typically rated at LEAST 125%
* if adding the accuratly calculated current home
loads . .and the addition of the accuratly
calculated proposed NEW loads do NOT still exceed
a continous load of 80% of your current main panels
supplied service
THEN PROCEED.

havent done any of this? . .spend a couple of bucks with a local Sparky and have him do these calculations for you . . .the inspector is NOT an electrician . .and wont lose a nap if yur Casa burns to the ground
get some peace of mind and do the above

tell us how it turns out

Plugging in 20 devices does not constitute an overload, only when you turn 'em all on at once.

Read the last line of the original post, the outlets are only for convenience, not to use at once.

All that said I combined the 120 and 240 by running 12/3 and put a 120 duplex and 240 single at each location. Saved a lot of duplication.

Only tripped the breaker when I jammed the saw.

"Plugging in 20 devices does not constitute an overload, only when you turn 'em all on at once."

I agree. All this talk about continuous load and 80% rules are meaningless in a residence, even a shop with a lot of tools.
A power tool is NOT a continuous load in a residence.

Wow, 30 120v receptacles in a single shop sounds like a lot, as does 8 240v receptacles. I've had two garage woodworking shops and never came close to needing that number of receptacles. My experience is that after a while tool placement becomes more less fixed. Obviously I know nothing about your work habits and don't want to appear too presumptuous.

What I did find useful was to two duplex receptacles in a 4" box but on DIFFERENT circuits. Lets say, for example, I was using the router table. Besides the router I needed some kind of dust collection. Obviously the two tools will be relatively close together. The router pulled 15 amps and the shop vac or dust collection 7+. With two different circuits in the same box, I didn't have to worry about tripping a breaker.

If possible I'd also suggest running dedicated circuits for your large, stationary tools. There were plenty of occasions I used the jointer and table saw at the same time. I also used overhead, drop cords for those tools. Keeps stuff off the floor, eliminating trip hazards and makes clean up easier.

The last thing is one of those self-retracting extension cords that mounts on the ceiling. That thing was so handy when I needed power but with just a tug it was out of the way.

Good luck with your new shop!

My "about 15 on each circuit" is actually 12 after counting, and three of those are in the ceiling, (one for garage door opener, and two for cord reels) and one is one the front wall (outdoor outlet.) That leaves 20 receptacles on 4 walls that are 22 and 26 feet long.

As far as 220 goes, other than dedicated circuits for compressor, dust collection and my PTAC, I am putting 2 on each wall. That will give me flexibility with tool placement, but 2 tools per wall is not overboard, even in a home shop.

I hate having to search for an outlet, and it is so inexpensive and easy to do while there is no sheetrock hung/