I've only installed a few "Ansul" systems, Iwire, so I am no expert. However, here it is required, when the system is tripped, that ALL sources of ignition be disconnected, as well as make-up air be stopped. This meands that the lights under the hood, any receptacles, and all electric equipment be shut off- in addition to the gas being shut off.
You are quite correct; the circuit only powered the controls and the gas igniter. Were these deep fryers to be all electric, they would likely need a 100 amp circuit. (Bit much for that extension cord!)
