From a double pole 20-amp breaker, I ran 12/3 w/g to a quad box with a 120 receptacle and a 240 receptacle. Red wire from one pole of the breaker to the 240, ground to the grounds, white to neutral bar in the panel and then the 120 outlet, and black from the other pole of the breaker to the box where it's pigtailed and split to the 120 and 240. The inspector failed me because this "produces uneven loads on the breakers".
I'm confused because everything I've read/seen indicates that this is exactly how to run such a circuit and the inspector could not well explain the problem or point it out in the code. Worse case if I run a tool drawing 20 amps on the 240 and plug something in drawing 10amps on the 120, both poles trip no harm no foul. I don't understand the problem or what exactly in the code I violated. He wants me to add another breaker, pull another wire, and put the 120 on its own hot.
Best Answer
According to 210.4.c of the NEC MWB shall supply only line to neutral loads. With 2 exceptions. #1 supplies only 1 utilization equipment. #2. All ungrounded conductors opened are opened simultaneously by the branch circuit OCD. Because of this wording many inspectors won't allow line to line to be used but it is legal , if you have a NEC hand book you can even see an example exhibit 210.2 that I have used in the past for an air conditioner and standard outlet in my case it was a 20 amp 240/120 outlet. How do they know what you are going to plug into it?