I recently had a new range installed and when an electrician was visiting, he pointed out that the circuit was over capacity because the range was rated at 12.2KW at 240V. He said 12,200 W / 240 V = 51A minimum.

However, I told him that the specs and installation guide state that the range only needs a 40A circuit and the manufacturer confirmed that this isn't a mistake.

So what gives? Is the equation the electrician is using incorrect?