904.11.2 of the International Fire Code requires the actuation of the fire extinguishing system to automatically shut down the fuel or electrical power supply to the cooking equipment.
So what I usually see is an ANSUL button close to the door leaving a commercial kitchen that activates the fire suppression system and also disconnects the power to the kitchen equipment.
I am not aware of any code requirement for just a EPO button to shut down the power to the kitchen equipment without also initiating the fire suppression system.
Chris