Would a relay that's meant for mains AC work for 13.5VAC? If not, what type of component/circuit would be best suited for this application? This is meant for a door buzzer/opener that functions on 13.5VAC. Thanks.
If the coil is designed for 120/240VAC, it probably won't work if driven with 13.5VAC. If you're driving the coil as specified and the contacts are rated for 120/240VAC, they'll switch a 13.5VAC signal without any problem.