Ok i didn't notice the "to the lights" before, so this is feeding the hot side of the light switches.
Can i step back a minute and revise my original post? What i should have mentioned in the first post, is that i am looking for a scenario where many lights up to 100 could be turned on and off by 3 or 4 way wall switches. Are we still on the same page?
The load can be anything. In a design you work from the load back to the service.
Let's say the load is 50 x 400 watt HID street lights (very common). Now you need your load side of the contactor rated at 50*400 VA = 20kw minimum.
As to the control side, that does not change. You'll order your contactor with a control voltage equal to what you have available, and the only power going through that control side is whatever it takes to switch (and hold, when applicable) the load side.
I measure about 20 watts load on the control side of a contactor which we're describing here (50 lights on a highway), and 20W can be handled easily by most 3 or 4 way switches. So your answer is yes, it can be done. It seems odd that you'd have 3 or 4 way switches on a circuit like that, but that's the question you're asking.
In Europe where they have a dedicated grid for outdoor lighting, it's not uncommon for a city or village to have only about 2 controls for the whole area. Very inefficient with very high inrush, but that's what they do.
Switching multiple loads at once causes very high inrush. Having a control at each light, or more controls, reduces the inrush overlap thereby reducing overall inrush.
