Lighting contactor
Figured this one out today, just a simple square D lighting contactor but this is my first one. Essentially we have a photo-eye outside, that receives 120V straight off a breaker from the panel. The neutral for this photo-eye goes straight to the neutral bus in the panel. The L2 on the photo-eye comes and hits the coil. The neutral for the coil jumps from neutral bar in the panel. We run a constant hot to the top contact, straight off the breaker. On the bottom contact would be your common 120V with all your lights in the circuit. The 120V feeding your photo-eye stays, it switches L2 hot when the sun goes does, L2 hits your coil, coil pulls in, contact closes, and now your common 120V to all your lights gets 120V from the constant on the top side of the contact. This is a good simple way to learn contactors. I made a little jigged drawing to explain it a little better