I've used that particular photocontrol in a variety of different applications, up to it's rated load (the 4- 400 Watt @ 208 Volts included), and never had a problem with its longevity.
It's MADE to take the load, otherwise Intermatic wouldn't make it, and rate it as such. Contacts weld on contactors, too.
It's a switch, nothing more, nothing less. In that mode of thinking we'd all be installing oversize switches, or contactors, on everything.
Yes it has a white wire, it's not a neutral (except for 277 volt applications) It's listed as a unit.
I agree with the the fact that the OP needs to hire a qualified electrician to service the installation, and the electrician needs to turn off the power at the circuit breaker. I don't think anybody qualified would consider the P/C to be a disconnecting means.
