Originally Posted by fishstein
"It's not a good idea to drive two unbalanced loads with one ballast. I'd change the electronic ballast and check all wiring. Pay attention to age and moisture. Check for good isolation between the driving elements and ground. Most electronic ballast are designed to drive 32 Watt 4' T8."
So I should not be mixing a 32 watt ADV850 bulb with a 36 watt Aquarelle on the same ballast? Would it be better to drive 2 36 watt Aquarelles on the same ballast and two 32 watt ADV850s on the other? It's also possible that my ballasts are not designed to handle the 36 watt bulbs - I might need something a bit more robust.
By checking aging and moisture, do you mean to check moisture and cracking on the wires? There's no visible damage and it's highly unlikely given where the wires are.
How can I check for good isolation between the driving elements and ground? I'm not an electrician - can you be more specific?
I sincerely appreciate your advice. This is a major safety issue I have to solve.
I'd check the specs on the new ballast to see if it is rated for 36 watt. Most commercial stuffs have a 10% tolerance, so you're probably okay. Yes, I would not run a 32 watt and a 36 watt off of one ballast.
I would expect more oxidation at the ends of the wire since these are exposed to higher than average humidity. Copper will turn green when oxidized. You may want to tin all copper terminals apply RTV silicone to improve corrosion resistance.
Use an ohm meter to check the resistance from the power terminals to ground (usually the metal reflector). Anything under 100 ohm is suspect. Also make sure the body of the ballast is grounded to the 3rd round prong of your AC plug.