Why must power exhaust for automatic fired equipment be connected in series to each piece of equipment?

The requirement for power exhaust systems to be connected in series to each piece of equipment is primarily to ensure safety in the event of a failure. When exhaust systems are configured in a series, the failure of any one component or the power exhaust itself will prevent the operation of the entire system. This design is critical because it mitigates the risk of dangerous conditions that could arise from equipment running without proper ventilation or exhaust. In applications involving combustion or heat generation, effective exhaust is crucial for removing harmful gases, smoke, and heat from the environment. If the power exhaust fails and the equipment continues to operate, it could lead to hazardous situations such as the accumulation of toxic gases or overheating, posing significant risks to both personnel and property.

The other options, while they may reflect some operational aspects, do not directly address the core safety concern associated with the exhaust system, which is the primary reason for the series connection.