Where are most safety controls wired?

Most safety controls in HVAC systems are wired in series with the load for a crucial reason: this configuration ensures that if a safety control is activated, it interrupts the operation of the load, such as a compressor or fan. In a series circuit, the current flows through each component sequentially, and when any safety control, like a high limit switch or a pressure switch, is triggered, it opens the circuit. This action effectively shuts off power to the load, preventing potential hazards like overheating or system damage.

This wiring method is essential for maintaining safe operation because it allows the safety devices to act as fail-safes; when conditions become unsafe, the safety control will stop the operation, providing a reliable means of safeguarding the system and its components.