Putting in a dedicated power line. 2 receptacles ok?

 with the grounds on opposite legs in the breaker box.

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I'm not following you. There are opposite legs in your breaker box for ground?

L1
L2
Common bus bar
(bridge bar (remove or leave) between common and ground)
Ground bus bar

Where is the second ground bus in a 220-240 single phase main?

L1 and L2 maybe.. Separate? Not a good idea that is how you get a ground loop.. Use only one dedicated 20 amp or a second BUT on the same bus, not the other.. L1 only L2 only, don't mix and match..

Regards

Two is not an issue, on the same rail in the main box is. You have 2 120 vac rails. Use only one of the rails in the main.

As for the outlets you can have as many as you want, but remember the length of the wire/cable.  The further the run the higher the likely hood of an antenna affect, RFI EFI.

If you use the other leg (RAIL) you can create a ground loop. Do you understand? The difference in voltage between the TWO rails L1, L2 is usually where the noise happens. SLIGHT voltage difference, thus ground loop noise.  Because different gear is on different rails, (L1 and L2) in the main and common cabling between gear, we can create NOISE. 

I won't put up with it.. mine is dead quiet because of that alone.
Using only one side of the HOUSE MAIN... Keep the grounds and common separate in the main too.. Whole different story..  I've seen a lot of mixing the two together. Things work BUT there is a lot of voltage leakage in the circuit because of it.. Mixing the two only increases noise potential. Sometimes it's very difficult to track that type of noise down..

Regards

That's ok if it makes sense to you.. It still doesn't to me.. BUT who the heck am I.. I think I'll stick with what I've been doing.. I mean I did build the house. NOT somebody else I built it, wired it, and and now repairing it after 40 years.. BUT hay, I'm just al ol mechanic..

Being able to do, rough wiring, pole work, troubleshooting, or finish wiring is NOT a hard thing to do. BEING fast and making it look professional is Pure repetition and do the good ones pay. For that a decent electrician in new construction it's almost worth hiring just for the speed alone. Cool thing my brother was the BA for the IBEW local 302.  With a little research you can figure out who I am.. NO lack of UNION Electricians around here.. Electricians, Mechanics, Cops, and Killers, My family!!

Regards

I think the question is terminology.

There is a single ground bus and a single common bus, NOT keeping the two separated in the main box could cause noise.

By removing or leaving the BRIDGE between the two (common and ground bus) they become one or removing it splits the two buses. It is a VERY common practice, to see a jumper between the two.

It may have been an easier way to explain two grounds vs the practice of having a jumper between the two and REMOVING it. He separated the common bus from the ground bus and cleaned the customers main to reflect that..  Older homes you see it ALL the time..

SPLIT the two and remove the bridge..

Load 1 or Load 2, take your pic but NOT both. You can add 6 breakers just hook them ALL to L1 or L2 not both to equal the load (not that much of a load now anyway)

The old SS Class As could suck the pole dry, still do for that matter. 220/240 is a better option for them.

MC is using a step down from 220/240 to a singe common rail of 120 (if I remember correctly) he’s got a different set up than most. Running HD class A on his system would be no problem, but for the common man they may have to split two 120 vac load between L1 and L2 and result in noise.

It’s all about leakage from the ground into common via the main OR subpanel lay out.. Who did what WHERE, kind of thing..

Clear as mud..

Told ya, clear as mud.. LOL

As long as it works. Who the heck cares?

Regards