CR-21 Landscapes and Irrigation Practice Test

Transformers for irrigation are fed from standard line power and then step that down to a low-voltage output for the valves. In most residential setups in the US, the line voltage you supply to the transformer is 120 volts AC. The transformer’s secondary side provides 24 volts AC to operate the sprinkler valves. So the voltage needed to run the transformer is 120 volts. The other voltages relate either to the low-voltage output (24 V) or to different contexts (277 V for some commercial lighting, 220 V used in other countries), not the typical residential irrigation input.