The first thing you need to know is how many AMPS are being fed into the breaker box that you intend to wire to....
Most residental breaker boxes these days are 200 amp service. Other breaker boxes may be wired off of the 200 amp main service. What you have to do is figure up the entire load from the breaker box, by looking at each of the breakers individually...they will have the rated amps on the end of the breaker switch. Most household breakers are 20 amp, and others such as electric dryers, kitchen stoves, etc. can be 30 to 50 amp breakers.
You add up the total off each breaker, and that's the amount of amps your using from that breaker box. DO NOT exceed the totally amps that the main breaker box is rated for!! If the breaker box that your wiring to is a 100 amp box, and all the breaker in it add up to more than 100 amps, your asking to burn the whole place down!
If your wiring a new circuit ONLY for the grinder, a 20 amp, double pole breaker is all your going to need. A breaker for 220 will be like two breakers built together. It will take two slots in the breaker box, and will have two switches that are connected with a small metal rod between the two tabs.
Here's a pic of the actual 20amp double pole breaker that powers my grinders....
The two 20 amp switches in the middle is the 20 amp double pole breaker that feeds power to my grinders. The two single pole breakers in the photo are to single plug ins in the shop.
To wire this breaker you put one black wire into each of the connections on the breaker (or one black and one red wire if your using a 4-wire romex), the white wire goes to the "common" bar inside the breaker box (you'll see all the other white wires connected to the common bar), and the green wire (the ground) MUST be attached to the grounding bar inside the breaker box. (sometimes the ground wire is a non-insulated wire). Use no smaller than 12 gauge, solid copper wire.
Just to be real clear on this....I'm not an electrician! IF YOU DO NOT FULLY UNDERSTAND WHAT YOUR DOING, I HIGHLY ENCOURAGE YOU TO EITHER HIRE AND ELECTRICIAN TO DO THE WIRING FOR YOU, OR FIND SOMEONE YOU TRUST! IF YOU DON'T DO IT RIGHT, YOU CAN EASILY BURN YOUR PLACE TO THE GROUND! This might sound dumb, but I can not be held accountable if you mess up.
One more warning...don't use that 100 amp breaker if all it's running is the grinder. Its not only unsafe, but in most places you'd be way overloading the breaker box, and that's generally unlawful.
General rule: Never have more total breaker amps fed through a breaker box, than the main breaker that it's fed off of.