Power exhausters serving automatically fired appliances must be __________ to prevent operation when the power exhauster is not in operation.

Power exhausters serving automatically fired appliances must be electrically connected to ensure that they operate in conjunction with the appliance. This connection is crucial because the exhaust system's function is to ventilate the combustion products and maintain safe operating conditions. If the power exhauster is not operational, it could lead to the accumulation of hazardous gases, creating a risk of unsafe conditions.

An electrical connection typically involves using interlocks or controls that automatically enable or disable the power exhausters based on the appliance's operation. This safeguard prevents scenarios where the appliance could potentially run without proper ventilation, which is vital for both safety and efficiency. Thus, the electrical connection serves as a critical safety mechanic to ensure proper functionality and compliance with code requirements.