If a range has a tag, which says it will draw 75A at full load does it actually draw that much with all elements on? If so, how can a 50A breaker hold this load?
To get 75A you will have to turn on everything at the same time. Having everything turned on at the same time isn't enough, since the oven will have a low current draw once it is warm.
Most, if not all, types of overcurrent protection allows a current exceeding the rating for a limited period of time. The wires will take a significant time to become warm. Ordinary breakers have a thermal element that heats up, just like the wires. When it gets too hot, the breaker trips.
Without access to trip curves for American breakers, I can't give you any exact figures. But I would guess that you can take out about 125% of the capacity for half an hour or more. For a few minutes, I'd expect the breaker to allow 150%.
Remeber that you are starting with the breaker cold when you turn on the range to get the maximum load.
If I just had my new range installed and properly wired up by a licensed electrician, I would be VERY upset if the code allowed my breaker to trip!
I on the other hand would be upset if the electrician oversized the wiring, since it costs me money. There are other things in life to spend money on than wire. I don't mind the breaker tripping sometimes. Even if it trips once a week, it will take a century or so before it wears out.
