I was thinking of maybe using a photocell to a three pole 120V coil A/C contactor to control multiple light fixtures at once. Like they used in commercial lighting.

So should I use a 120V coil A/C contactor or a lighting contactor. I was thinking of this to control my streetlight fixtures if I get them, and yes I'll use the shorting caps on the fixtures.

That should be perfectly fine.

Seems fine as long as it can handle all the amps and u wire it right

Seems fine as long as it can handle all the amps and u wire it right

I found a Mars 3 pole 120V coil contactor of Amazon.com that can handle FLA (foward line amprage, I think) current of 40A. Although, I could use a 2 pole contactor, since i'm probably gonna use four to three streetlight or HID fixtures.

I found a Mars 3 pole 120V coil contactor of Amazon.com that can handle FLA (foward line amprage, I think) current of 40A. Although, I could use a 2 pole contactor, since i'm probably gonna use four to three streetlight or HID fixtures.

Be sure to check the inductive load current rating in the datasheet (the inductive loads cause harsher arcing than resistive, so typically inductive load rating use to be 2..5x lower than resistive load one; it is specified in the detailed datasheet).

FLA stands for Full Load Amps. It is a motor rating, so seems like equivalent of AC-3

LRA stands for Locked Rotor Amps