dgardner
Moderator
Often times I plug in the dwell pro machines to 15 amp breakers. The Duel 6.6 vac motors that is. It usually won't trip for a few hours even though it's running 18-19amps.
Mr. Dwell is right - so I guess I should touch on this. The characteristics of a typical breaker is a curve rather than a hard trip point. With enough of an overload they trip nearly instantaneously, but with smaller and smaller overloads they take some time to trip. The breakers we encounter aren't guaranteed to trip until about 125% - so a 15A breaker may not trip at all until 18A or so, or may take hours to trip. At 19A, the typical curve says the breaker could take anywhere from 150 seconds to 2000 seconds to trip, so you can't count on it to work every time.
Now, the electrical code says (for a 15A outlet, even if on a 20A circuit) you should not connect a load greater than 12A. So - sucking 18A out of that outlet is really pushing things. It stresses all the components (breaker, wiring, connections, outlets) and if they are old or have loose connections the heat buildup could really ruin your day. I just say this so all will realize the liability they are taking on by doing so. Your choice, more power to you! (pun intended). Can you get away with it? Probably.....
I will say that if a manufacturer were to take an appliance to UL to apply for a listing that had a standard 15A cord and drew 18A they would be laughed out of the building. In fact even a 20A cord/plug would be rejected if it drew more than 16A.