I have an 8ft/4-tube/electronic ballast fixture that has recently started not coming on reliably. Most of the time it works just fine, but about once a week it won’t start- but usually will with a rap with a yardstick (most anywhere- not any particular spot). Either everything works or nothing does. No flicker, hum, etc. It’s about 5 yrs old and is the first wired in a series of three- no problems with #2 or #3. Tubes are fine and all connections seem tight.
Replace ballast? Re-check connections? Suggestions?
thanks in advance!
Ok- i never found anything wrong last time around, ground was tight, tubes good, all connections seemed fine, etc., and it has been working normally… until this morning. after it had been on for about 30 minutes it went FFFZZZZTTT and died. everything looks fine (but obviously something isn’t) with ONE EXCEPTION: the bare copper ground wire (14g romex) is blackened for about an inch of its length, about an inch away from the shiny tight ground screw. in other words, it’s clean & bright for an inch or so back from the screw, looks scorched for an inch, then is perfectly clean from there on into the romex sheath about 6″ away. there is absolutely NO evidence that it arced to anything else and, with the exception of the sheet metal housing of the fixture, it wasn’t even close to anything else. it’s also possible i overlooked this the last time i was poking around in there and it’s unrelated to the latest incident (could be a reused section of romex from the major remodel of this bldg).
in any event, i’m going to replace the ballast and see if that fixes everything. (in case y’all are wondering, i have a lot of experience with the old lead ballast* T12s, but this is my first long-term encounter with the newfangled units. *when i was 16, working for my dad’s const. co., i was in a warehouse up on a 24′ ladder unscrewing a ballast that needed replaced. about a half turn from removing the screw, my brother says “be careful- they’re heavy!” – it took out a couple more fixtures on its way to the floor…)
Replies
Check sockets
Probably not the right name for the contacts at the end of each bulb, for lack of a better word, I'll call them sockets.
If your 8' fluorescents are covered, remove the cover from the fixture which gives you trouble.
Next time the fixture refuses to light - don't whack it ---- wiggle each socket on both bulbs.
If the light comes on - replace that socket - cheap and readily available - generally sold as a two-pack.
Don't think it is the ballast, as whacking the fixture will not do anything to it - I suspect you have one bad / marginal socket.
Good luck!
Jim
The quasi official name is "tombstones" for the lamp holders.
Tombstones
Wunner what the chances of an "associate" at HD knowing that ! They would probably say something like - "well, I don't think so, but they have some stone over in the lawn and garden center, ya might check out there........." :^)
I can see it though - they look kind of like a tombstone. Lamp holder sounds good - better chance with that one I think.
Jim
A tombstone is something I'd never even bother checking HD for. Much better chance of finding it at one of the couple of remaining decent HW stores nearby.
Actually....
My local HD stocks them in blister packs of two - but I just never paid any attention to the name on the package. I'll have to look next time I'm over there.
They are with the replacement starters and ballasts.
Jim
It may be simpler than that.
Perhaps a tube just has to be seated a bit better in the socket. Give it a slight twist. Else, replace the socket.
If it's not a lamp mis-seated in the socket...
or a lamp with a bad pin, then it's probably a bad splice.
Check the grounding connection (to the fixture itself) first. Fluorescent fixtures need a solid grounding connection to reliably fire off. The grounding wire of the building wire needs to be connected to the metal of the fixture with a 10-32 machine screw (or similar, not a sheet metal screw), and it's good practice to scrape off the paint from the sheet metal so the wire contacts bare metal.
If the fixture is well-grounded, and the sockets look good, and you install new lamps, time to open up the fixture. I'd re-make all the splices, occasionally one of the ballast leads breaks inside it's insulation. Not visible, and can create an intermittent open. Cut back the leads an inch or two and make sure to use a small (real small) wirenut. A common yellow 'nut is too big, won't give a reliable connection of two # 20s.
If it's not grounding, mis-seated lamps, bad sockets, bad lamps, or the splices, it might be a bad connection at a socket. Some sockets can be removed easily, others require partial disassembly of the fixture. The sockets have poke-in terminals, not the best kind of connection, but good enough if done right. That means stripping 1/2" of insulation off the wire, poking it in, and then pulling back slightly so that the teminal grabs the wire.
I'd lay odds on a bad ground. It's because just touching the fixture makes it fire off. A bad connection or mis-seated lamp would require a bit of a jostle, a tap or bump, to cause the lights to go on.
Good luck.
Cliff
loose ground sounds most likely...
i'll check that next. it's probably not the tubes, or pins, because turning or jiggling them does not turn the light on. i suspect a loose ground or perhaps another minor disconnect in part because my shop sits about ten feet off a semi-public rough dirt road and i've noticed other subtle signs of stuff moving from vibration over the years. also, of the three times it's happened and i turned it on with the yardstick trick on the housing, once i rapped the south end, once the north end, and once amidships. an ever-so-slightly loose ground seems the most likely culprit at this point.
thanks to all!
First thing to try is to simply remove and reinstall the lamps.
umm, okay Dan...
don't you think if i'd already tested connections, etc., i mighta already tried that one before bothering to post a question here? not that i don't appreciate the help, but i was looking for something a little less obvious. and before you ask, yeah, i tested all the tubes in another fixture, too.
i wired all these three fixtures in about five years ago, along with ten more in the larger room of my bldg, and everything has worked flawlessly since day one. now one has developed an annoying minor glitch the cause of which has not been revealed by the usual checks...
The next suspect would be the bad ground thing. Getting a fixture to start by simply touching it is typical of a bad ground scenario.
After that I'd suspect a bad ballast.
BTW, it might not be the entire fixture that's ungrounded, but maybe a shield or some such that's not making contact as it should.
Did not see a good discussion of ballasts yet. If your present ballasts are magnetic vs. electronic (magnetic ones are heavy, electronic lightweight and usually say electronic on them).. go on ebay or surplus center site, buy a 10 pack 4 tube electronic used ballasts for about $50 plus shipping, and replace all your ballasts. Recycle the old ones. Payback time per ballast is about 4-500 hours of light operation per fixture at used ebay prices and 10 cents/kW-hr.
edit -- and yes, I have replaced all my 4 ft t12 ballasts wityh T8 electronic ballasts - about 35 of them total, have over 120 4 ft fluorescents in various places, most are just 2 tube, but 3 and 4 tube ballast work very well for 2 tube fixtures. It helped finding cases of 15 T8 tubes for $1 per case at a garage sale <G> No problem finishing off the T12 withthe electronic ballasts either..
My guess is check the tombstones/lamp connection to make sure they are good ... assuming your other connections are solid, that'd be my guess. A bad ballast might be pretty unusual.
Did you know you aren't suppose to install/remove fluorescent lamps w/ the fixture on? The arcing affects the lamp ... can't remember exactly what it does. People (even I) do it all the time, though.
clean...
clean the tombstones and bulb contacts with a pencil eraser..
spin the mounted bulbs in place after instaltion....