Q: 120V output relay from AC or DC What's the best method to switch a ≥15A 120V AC relay using both a 24VDC input or current sensing a 120VAC load. In other words, the NC relay will open if either (1) there's a load on a 120VAC line (>100mA), or (2) if 24VDC is applied to the relay, or (3) if both occur at the same time.

A: I guess the 'simplest' way is using a current sense relay for the load sensor and a simple 24VDC relay for the DC input. Contacts in parallel switching the coil of your power relay (you didn't spec the coil for that).
I said simplest, not cheapest, of course.
