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#30937 11/03/03 01:22 PM
Joined: Nov 2003
Posts: 2
Neal Offline OP
Junior Member
I am an electrician who is stumped. I suppose that I could work this out in time but I have never run into a problem like this before. Recently I installed two new T8 ballasts in two separate 48inch T8 fixtures. Replacing the 48 inch T8 tubes I discovered that ony one tube will light at a time. The addition of another tube, completing the fixture's tube complement, results in no hint of a lighting, the first one introduced remaining lit. On the other hand, loosening the first tube results in the second one firing up immediately. Twisting the first tube back into its ceramic fittings results in no light whatsoever! Should I reverse the polarity of the wiring emanating from the ballasts. It seems that reversing the tubes should achieve the same result. I tried that too, but no change in the result. As stated before, this phenomenon is happening in two separate fixtures! The ballasts labeling say that it will fire up two T8 tubes, so what is going on? What has this old man overlooked? This is embarrasing having been in the business since 1959. I've never experienced a situation in florescent lighting that I could not resolve -- there's not THAT MUCH to it! Oh woe! Thank you, Neal

#30938 11/03/03 04:35 PM
Joined: Oct 2003
Posts: 289
as you said this ballast can fire 2 tubes, is it an electronic ballast?

if it is, there are some that only start properly if both tubes are inserted and working. i've experienced this through changing tubes on electronic ballast while the lights were switched on.
Set one tube, works. Set the other, goes out or does other strange things whatever. after switching of and onn, both lit.

[This message has been edited by :andy: (edited 11-03-2003).]

#30939 11/03/03 07:41 PM
Joined: Feb 2003
Posts: 939
ok there are some lumaires ballast it should show the connetion digram for it and i know some ballast have limit for so many feet/meter away from ballast so i suggest to recheck the connetion digram and check the tombstone again ( flourscent socket) make sure it dont have cutoff device inside of it

merci, marc

Pas de problme,il marche n'est-ce pas?"(No problem, it works doesn't it?)

#30940 11/03/03 08:06 PM
Joined: May 2002
Posts: 132
I agree with previous poster. Double check that the sockets and wiring are as per the diagram on the ballast. I have had it happen a few times that it would arrive from the factory either wired wrong or sockets in wrong arrangement. What gets me is that it will state right in the box that the fixture was tested at the factory??????WTF?????? Let us know what the verdict was.

#30941 11/03/03 08:13 PM
Joined: May 2002
Posts: 1,716
Neal, as Andy and Marc point out the T8 electronic ballast don't rime or reason the way the old magnetics did. Check the wiring diagrams closely and then go to the manufacturers web site for trouble shooting if your supplier can't give you some assistance.

BTW, Welcome to the forum and stick around, there are mighty fine people and a lot of good conversation here. [Linked Image]


#30942 11/03/03 09:53 PM
Joined: Nov 2003
Posts: 2
Neal Offline OP
Junior Member
Hi Guys! Thanks for the welcome. I shall take all your advice under serious advisement. The fixtures worked before with the same sockets; I merely replaced the ballasts with new ones as well as replacing the tubes. Except for the sockets, of course this constitutes rebuilding the fixtures. Based on what you each have said, I think that the idea of placing both tubes in the units and then turning on the switch seems most logical. I'll give it a whirl and let you all know what happened. Thanks again! Neal

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