Cool fixture I always loved those Unistyle 175 fixtures (Probably because my street was lit by them when I was a kid)
Sadly I never got one
Are you actually using a Metal Halide lamp or is that a Mercury Vapor lamp and also what happened to the original ballast?

This is a MH ballast but he's running a MV lamp. When he got this, it didn't have a ballast but the original ballast would have been either a 100W or 175W MV, 240V with a 120V PC socket.

OK Cool how do you run a MV lamp on a MH ballast? I assume you have to disable the ignitor if so how? Also it MV to MH watt to watt meaning a 100W MH will run a 100W MV fine or would I have to go down a step?
Thanks

This ballast didn't come with a ignitor because it is a regular MH ballast, not PSMH. I usually don't run my lights for more than a hour or two so it should be fine

Regular MH ballasts will run MV lamps perfectly without any modifications. For PSMH ballasts, disconnect the white wire from the igniter and cap it. To run a 100W MV, you can use either a 70W PSMH ballast or a 100W PSMH ballast, just disconnect the igniter first. If you leave the igniter connected, you'll fry the internal starting resistor, which means it'll become a pulse-start MV lamp lol.

Nice fixture! Sadly, LED killed off the last Unistyles in my neighbourhood earlier this year..

100w PSMH also works great with 125w MV lamps if you want that extra brightness.

@Mike, does that go for all wattages of regular MH ballasts? So if I wanted to run a 100 watt MV lamp, a 100 watt MH ballast will work? And I thought when using a PSMH ballast, it's better to run a 100 watt MV lamp on a 70 watt PSMH ballast?

Both will work. A 100W PSMH ballast will slightly overdrive a 100W MV lamp, but that's not bad since a lot of cheaper 100W Mv ballasts do the same thing. For regular MH ballasts, mercs will run without modification for 175, 250, 400, and 1000W.