CET Class 2 Transformers
A Class 2 transformer is one that delivers 100VA or less with a maximum output voltage of 30VAC or less. They are used in applications ranging from air conditioning thermostats, garage door openers, sprinkler system controls, digital controllers, gas controls, ignition systems, motor actuators, staging controls, the food and beverage industry and most other Heating, Ventilation, Air Conditioning, and Refrigeration (HVACR) control systems
Their low voltage output means they are considered safer than other transformers because the low secondary voltage reduces an electrical shock hazard, and the low power output reduces a fire hazard. The current is also limited either by a fuse or by the internal impedance of the SEC winding (known as inherently limited).