Final answer:
A circuit breaker is required to open and close the main power source to most heating, cooling, and refrigeration equipment.
Step-by-step explanation:
The type of switch required to open and close the main power source to most heating, cooling, and refrigeration equipment is a circuit breaker.
A circuit breaker is a safety device that detects an overload or short circuit in the electrical system and opens the circuit to protect the equipment from damage and prevent electrical hazards. It is designed to react quickly and can be reset after tripping.
One of the safety features of modern household and industrial wiring is the use of circuit breakers to prevent thermal overload or electrical shocks.