Electronics drawing lots more amps that it should
First issue here  is safety. With 12 AWG wire on circuit, circuit breaker should not be larger than 20A. This is  code violation. 

OK, where are you measuring the current? On the common wire going into panel? If you have x amps current leaving panel on one conductor on 240 VAC circuit, then must have same current going back to panel on other conductor. So 11.9A total current x 240V =  2856W. Divide that by 2 = 1428W. Sounds about right to me.