Okay.  This is an international site, so we're all kind of guessing a little here that our electricity is the same.  Mine is 60 Hz 120 VAC.  Who knows what yours is, you didn't list your country in the profile.  But anyways, I would go with 60 amps if I were you, just to be on the safe side. Either way, make sure your wires are sufficient gauge to carry the load, and if you're using 240 VAC (U.S. style) that would be two 30 amp breakers in a 240 double switch type breaker.  39 amps is an odd size to me, which probably means it's the actual tested draw of the unit.