[Hangfire]

I've got a question I'm hoping someone on here can answer for me.

I picked up a Giesemann Metal Halide and T5 fixture. My question concerns the MH ballast. I'll try and be as clear as possible - I have two power lines coming from the hood itself - one is for the T5s and one is for the MH (it's a large white plug). There is a corresponding white plug on the ballast, but coming out of the white plug is another power line that you'd plug into an outlet. Where the heck does that plug in? On the other side of the ballast is the single plug I'm assuming you plug into the power supply, but I'm baffled as to where to plug in the extra power plug. It doesn't make sense that the current would come from the power source, into the ballast, up to the light, but also back to the power supply.

I hope this is somewhat clear.