175 W. Metal halide bulb in a 400W. Metal halide fixture

[zappy]

400W. HID Metal halide flood lamp with 175 Watt metal halide bulb screwed in. Is this ok? Thank you for your help.

 

[grich]

Generally, the bulb size must match what the ballast is designed for, or you'll have short bulb life, assuming it lights at all. It's been awhile, but I recall 35W HPS bulbs in a 100W fixture showed signs of overdriving and failed in months rather than years.

 

[mjf]

lamp should match the ballast.

I'd double check the ballast....someone may have changed it previously and put a 175 ballast into a 400 "shell"