I've seen all the questions about 240 to 120 outlets...
The 240 plug has 2 hots and a neutral (different then a 'ground'?? )
So if I run a NEW GROUND I can then take the neutral ad one of the not poles from the 240?

How do they get the sub-panels with 240/120 with no new ground run?

Also is it bad to have one outlet on a separate ground then the rest?

Two hots and a ground will give you a 240 outlet not the neutral. Everything should be grounded. If that sub panel is not grounded than nothing coming off that sub panel is grounded. For that outlet yes you could have a separate ground as long as it is going back to the panel. They have a tester that you could use to see if your outlets are grounded they sell them at HOME DEPOT or at any electrical supply store.

Use one of the 240 volt live wires, reconnect it at the panel from the breaker to the neutral bar, and you now have 120 volts with a ground at the old 240 volt outlet.

A subpanel that does not have an equipment ground run to it should have a ground rod grounding the neutral and equipment ground bars in the subpanel.

No, a separate ground is allowed for specific purposes.

This is in a small wearhouse, and I cannot put in a new ground rod ( a lot of cement) the run is fairly short I'm trying to add an office expantion with a 30A socket that currently has a 8amp A/C I want to tap into the socket (leaving the a/c working ) bring it 12 feet to the new wall, add another 240v socket for another 8 amp a/c and split off a 120 socket for a coffee maker light and vacuum cleaner, so if I bring my 240v over to the new local with a 10/3 I can make a sub-panel.. but isn't the black and white both 120V and the ground makes it 240v... with no neutral? If I'm understanding you guys right.

How can I break off a 120 socket from that panel.

Black and red are 240 volts, black and white is 120 volts, so is red and white, ground is bare or green and will also show 120 volts from black or red. So a 4 wire cable needs to feed a subpanel, and in this case the equipment ground needs a ground electrode, such as a ground rod, or a #6 to a city water line at the water meter, or building steel if the building is all steel frame.

I just went to home depot and sat for 40 minutes reading the electrical book they have available, and bought this black and decker book. Nice color images.
Unfortunately I have a 240/(250?) V with a 12/2 cable... I don't know where I got 10/3,.
Its riding both the hot rails and has a ground (according to the book) I'm not going to run a neutral from a socket... ill just add a down-steping transformer.. and plug the vacume in elsewhere... I saw a 1000W downstepper for 60 bucks... but I needed the ac extension so ill just extend the 240 and put 2 plugs one for the downstep..
Thanks for your help.