Moisture in Raintight Luminaire

[marmathsen]

My company recently installed 12 RAB VX100DG fixtures along a driveway at a customer's residence. We are having an issue with the bulbs burning out and moisture collecting in the glass. Does anybody have any experience with this problem and have any recommendations. I'm planning on going back out there and siliconing. Unfortunately I have since seen their spec sheet where they explicitly say that they shouldn't be mounted base down (they are) and that they should be siliconed where the base attaches to the "ceiling". I'm wondering if placing a silica packet or pellets inside each fixture would be smart or stupid. Suggestions?

-PS- Thank you Mr. Architect for designing this without reading the product spec sheet!

 

[GoldDigger]

I'm wondering if placing a silica packet or pellets inside each fixture would be smart or stupid. Suggestions?

If you are seeing a light clouding on the lens or a couple of small drops of water, silica gel would be a short term improvement, but would have to be replaced regularly. If you are seeing water rather than moisture, you will end up with wet silica gel and water.
The burnout may be the result of inadequate heat transfer or too high wattage bulbs.

The fundamental problem, IHMO, is that when used base down moisture/rain/etc can collect inside the threaded area where the globe screws in and then be drawn directly in by expansion and contraction of the air inside as the light heats up and cools down. It is OK for rain exposure, but not for "underwater" use which is effectively what you have.

I would:
replace them with a proper fixture for the application
shield the screw area from direct moisture accumulation (skirt attached to the globe?)
look at providing some form of venting so that the heat of the lamp can force the moisture back out.

What is on the other end of the conduits attached to the "waterproof" junction box, and are you using appropriate liquid-tight attachment methods?

 

[templdl]

My company recently installed 12 RAB VX100DG fixtures along a driveway at a customer's residence. We are having an issue with the bulbs burning out and moisture collecting in the glass. Does anybody have any experience with this problem and have any recommendations. I'm planning on going back out there and siliconing. Unfortunately I have since seen their spec sheet where they explicitly say that they shouldn't be mounted base down (they are) and that they should be siliconed where the base attaches to the "ceiling". I'm wondering if placing a silica packet or pellets inside each fixture would be smart or stupid. Suggestions?

-PS- Thank you Mr. Architect for designing this without reading the product spec sheet!

It may be just condensation which may be occurring when the fixture is off with not heat being generated. If there is enough humidity in the air within the enclosure and the temperature dips below the dew point there will be condensation. I'm also not sure if the enclosure in completely air tight as a simple change in temperature may draw humid air from the outside into the enclosure which can condense later when temperature drops.
In other words water from rain may not ever be penetrating the enclosure directly.