Temperature regulation in pottery kiln with 3 phase 400V

/dev:
It's the change in temperature over time (dTemp/dTime) that determines the stress on the elements.

Cheers,
/dev

That is the key point.

I had never thought it was a problem though with heater coils except at failure when a tired element suddenly undergoes localised heating and pops.

I understood the main problem was through gradual deterioration of the element due to oxidation etc.

Mind you I looked up the price of those kanthal elements.
I can see why you would want to molly coddle them.
I was left wondering how much gold/platinum was in the alloy