Well, lets see here:
575w x 4 units = 2300 watts / 120 volts = 19.16 Amps
575w x 4 units = 2300 watts / 118 volts = 19.49 Amps
575w x 4 units = 2300 watts / 115 volts = 20 Amps
575w x 4 units = 2300 watts / 113 volts = 20.35 Amps
Remember, your 2.4k dimmer doesn't actually care about the...