A 12 KW range in domestic use is considered to have a 8000 watt demand see 8-300. This is why we use 8-3 instead of 6-3 to feed a 12 kw range
8kw=33.33 amps on a 40 amp breaker
12 kw = 50 amps and in a commercial application X 1.25 or 62.5 amps on an 70 amp breaker
The range itself is different too.
A domestic range while capeable of using the full 12 kw with all 4 elements and both oven elements on high it does so for ver brief periods. Domestic ranges are not approved for use in a restaurant even though they often try to use them since they are 1/4 the cost.
The commercial range is rated for use the whole day, every day.
