I need help diagnosing a problem with Techlight 175W Mercury 2-fixture downlight kits.

I purchased three kits and installed them, all on the same circuit controlled by a 20A relay.  Prior to the installation I checked the 110V circuit and everything was fine.  Then I rented a lift and hung the fixtures, carefully connecting the 16/3 special wire to each fixture first.

The next day I wired them into the circuit.  When I connected the first kit I turned them on.  Both bulbs came on and began warming up.  After about a minute (or maybe two), one of the bulbs went off.  I walked back to the switch and turned off the circuit.

Then I wired up the 2nd kit and turned on the circuit.  Both lights came on, but neither light came on in the first kit.  The 2nd kit warmed up and worked perfectly.  I turned off the circuit.

Then I wired up the 3rd kit and turn on the circuit.  The 3rd kit never came on, the 2nd kit continued to work perfectly and the third kit still didn't come on again.

I triple checked the way I wired them, and all the connections.  Everything seems fine.  My little sensor says power is going up all six wires into the trees, but only one kit is working.  All are wired exactly the same.

How do I diagnose this problem.  Should I buy a voltage tester (what kind) and check the output of the ballasts?  What would I expect to find?  Any other ideas?

Thanks for purchasing our mercury vapor tree lighting equipment.  Sounds like you really thought this out and did a good job installing them.

As you know, mercury vapor lamps do not come on instantaneously, because the lamp has an arc tube and not a filament.  That means they take a few minutes to ignite and for the gas to come up to full intensity.  Likewise, they must cool off before they will restrike once they are turned off.  This might be one reason.

You might also have a neutral problem which could cause the lights to work intermitantly.  Each ballast has two neutral wires, one for the lamp and one for the ballast.  Make sure you connected both wires.

Please let us know if you got your tree lighting fixture problem resolved and how it looks! 

They have been installed now for about two weeks.  Nothing has changed, so the problem with kit #1 isn''t a problem with trying to start them again too soon.  How could they have worked, then gone off (literally while I was watching one just went off before it was charged up to full strength), and now won''t start up again?  Did something burn up (ballast, capacitor?) and if so, how would I determine it?  Power of some kind is going up the wires to the fixtures.

I''ve double checked the neutral wiring in the ballast boxes.  They are wired correctly (all 4 neutral wires are connected to the neutral 110V in each kit).  It is possible I have a neutral problem with the 110V at kit #3 (the ones that never came on).  How do I check that?

However, kit#1 remains a total mystery.  Something tells me if I can diagnose that problem and fix it, the problem with kit#3 will be similar - but I''m willing to check the neutral 110V connection to kit#3 to eliminate that possibility -if I only knew how.