20 amp requirement

I talked on the phone with a guy at Tormach about the 20A circuit requirement and was told it wasn't really necessary, so I went ahead and switched one of the 15A outlets to a 20A without actually changing the circuit. Now I'm having some issues with getting the spindle started on my new 770. As soon as I hit the spindle start switch, the circuit breaker flips and I lose power to the shop. I'm able to jog the machine and turn the controller on just fine, but I guess their draw isn't nearly as much as the spindle. Not being a big electric guy, I'm assuming this is because I actually do need the 20A circuit? Just want some confirmation before I call the electrician out. :)

Thanks,
Stephen