Most lamps have a specified operating position..VBU base up + or - 15 degrees...VBD Base down + or - 15 degrees...Lamps operated in vertical position Base up or down can be used in an open fixture..Lamps burned any other way must be used in "enclosed fixtures only"....Taken from the back of my bulbs packaging.
kRoNikLy420 Reviewed by kRoNikLy420 on . MH Ligh flashing I never used MH lights before I purchased a Brinks MH light 100 watt yard security light. Just paint the photo cell black. Brinks 100 Watt Metal Halide Area Light (7252) ( I paid 60 at walmart ) It said to mount so that bulb is vertical. However I mounted on a 45 degree tilt to the horizontal. the light comes on fine. but after a few moments the light gets very bright then flickers and almost looks like a HPS for a second. Is the bulb bad or does it actually matter how the bulb is hung? Rating: 5