Andrew, you're right to dedicate a circuit to your ent' centre. Receptacles are meant to be wired with #12 sheathed electrical cable anyway, so install a 20A breaker. If you have spare breaker slot, install a 20 amp circuit there, and run your power tools from it. Make sure you run the new garage circuit from the opposite 120 volt leg to the ent' centre circuit. In other words: fit the two new breakers directly above or below each other. This way, your power tools won't interfere with (flicker or blink) your electronic stuff. By the way, if you visit www.energysmart.com you will find a large selection of electronic, power- protection equipment. As well as "Power Planners" which reduce electricity use in the home and anywhere AC motors are used. We are distributors, and can give better pricing than the website. I hope I was able to help some. If you need more precise help, please call me at 800 851 9891. Regards, Brian.