Cable sizing for a stove.

[AndyD]

Just an observation and a subsequent question. In Canada we use the wattage information for load calculations when it is on the nameplate data. Also one of the things happens a lot here is manufacturers of the tops and oven are different and the two are not designed to be connected to the same circuit as there is no approved overload devices between the units to prevent the top from drawing too much current from a breaker that would be to large for the top itself.

The circuit breaker is sized to protect the cabling of the electrical installation from overload, not to protect the actual appliances that are plugged in or connected. If an appliance requires its own overload protection it must be built into the appliance or designed into the appliance. For example many stoves have an internal wiring arrangement that prevents all the hob elements and the oven running simultaneously.

The question is are you allowed to load a breaker and conductor to 100% in a residential application? Here the breaker is not allowed to loaded to more the 80% in residential but the conductor can be loaded to 100%. In commercial the breaker and conductor must be sized to 125% Do you do anything like that?

Yes, you can load a circuit to 100% of its capacity. There's sufficient safety allowances in the reference tables in the regs that dictate a circuits maximum load capacity so no additional blanket derating is required.