Relay AC performance and timing specifications and testing methods have been discussed here. The coil operation voltage can be 28V or more, and current can be as high as several hundred milliamps ...

These G9TA relays feature 2mΩ contact resistance, 6kV impulse withstand voltage, 250Vac max switching voltage, and 12Vdc coil voltage. The 120A (276Vac, or 100A with PF=0.5 inductive load) G9TB AC ...

Ok, software done; on to the relay controller box! [danman]’s sprinkler system has four 12V AC valves that need wrangling, and no data cables, necessitating the wireless setup.