Electrical Knowledge Repository - Finding Bad Fluorescent Ballast

Old EKR Archives: Subject - Finding Bad Fluorescent Ballast
Romex Racer	If you have 10 fluorescent fixtures wired together, like in a warehouse or something. If the ballast in one of those lights shorts out, it will trip the breaker and all the lights will go out. Now you have to open up every fixture, disconnect it and try the breaker to see which ballast is bad... A very time consuming job. Here's how to identify the bad fixture in seconds: Take the wire off the breaker and hold it against the bus. The bad fixture will be the one with the smoke and sparks flying out of it! In 27 years of wiring, I've done this a few times and it works every time! I know this isn't pretty, and some may blanch at the idea, but I learned this from an old hand who was the best electrician I've ever known.
Scott Vickrey	Being a creative type I can appreciate the fact that sometimes good results can be had from visionary methods. Some better than others I have no doubt that this method is fast and very effective. However, you know this is not the type of troubleshooting that can be condoned due to it's inherent danger to life and capitol. I can't say I have never seen anyone do this but, There is always a better way than this regardless of the time consumed. There are better ways!
Romex Racer	I also have a method to check the level of fuel in your gas tank when the gauge fails. It uses common household matches! :)
lctrc789	I know what you are saying this is out of the ordinary and in 24 years I have seen some pretty dumb, unsafe practices, but some of the old timers well you know what they say you can check voltage between two fingers LOL I have seen some of the old timers check for shorts in many ways, the best one I have ever seen is the old knob and tube wiring shorting out in a house and he had several of the circuit type fuses that reset with the reset button in them. He had me stay at the fuse box while he went upsatirs and then he called to me and said push the reset button and keep hitting it till I say stop. I did, it kept tripping I kept resetting, you know what he found the problem after the wire burned out LOL but never the less he found it. Of course I forgot to mention the fact that the atiic was smoking lol.
fgw	I've witnessed the "bypass the breaker" method of chasing down a bad ballast. True, it will work.... I've seen it with my own eyes. I thought the guy I was working for at the time was a little strange however, I learned alot of what I know about pipe work & circuit layout from him. I could never find the courage to try his method. Besides, I can make more on the job if I open each & every fixture to inspect or replace a ballast. Anyone have a "safer" method of chasing down a bad ballast on a string of fixtures? I'm always willing to learn & try new troubleshooting methods...
karlwayne	I am probably shooting from the hip, but I know there are people out there who know for sure. I think the ballasts manufactured after 1984 all have thermal protection in them. This may have been an excellent opportunity to make a sales pitch?
kbsparky	Engaging in such "troubleshooting" tactics can indeed work in some scenerios, depending on the nominal system Voltage, and available fault current. I would not recommend this procedure on 277 Volt systems, where the flash from the short on the buss bars could result in more than you bargained for. On systems that had a high available fault-current (even at 120 Volts), the short can also produce more arcing and damage than you were prepared for ..... oY!
Romex Racer	One time I was installing a light switch for some 277 volt fluorescents, doing it hot, accidentally touched the hot screw to the plaster ring and POW!!!! It was most impressive. I was too young in the trade to take the precaution of wrapping the switch with electrical tape.. Somebody mentioned shorting out a wire to find the breaker in a panel, I used to to that until I learned my lesson. I was working in a house owned by a famous female singer with a large nose and liberal politics, I shorted out the wire, sure nuff, no power, I go to the panel, all the breakers are on and passing power. After 3 hours of trouble shooting I found a loose wirenut that had "arc'd open"... I never did that again!
CooCooMike	the old smell test used to do it for me now with the electronic ballasts it's a little bit tougher but one way we used to test for shorts on 110 was using a 200 watt bulb.either screw it into the fuse holder or use a temp socket, full bright was a dead short,saved on fuses and resetting
John A. Peters	quote: Originally posted by CooCooMike test for shorts on 110 circit using a 200 watt bulb. Either screw it into the fuse holder or use a temp socket, full bright is a dead short, saved on fuses and resetting. Right. And then you could use an ampprobe to check for current along the circit, until you find the location of the short. Amperage means look farther away from the breaker, no amperage flowing means check closer to the breaker. Using a voltage sniffer might fool you, does any one know?
CooCooMike	never used an amprobe for that application but sounds like it might work
CooCooMike	one method i read was that people short out the ct to see which cb tripped. i remember hearing years ago that the manufacturer voids the warranty on a breaker after a direct short
skynrd	I would never condone the method of taking a shorted devise to the main buss for any reason. Example from experieince I was installing metal pancake mold in an arcade, through all the devices in and proceeded to hookup the breakers in a 200a sub panel while the place was open for business no problem my 20a breakers that I was hooking up were shut off. Anyway I stripped one wire turned my head to pickup my screwdriver the wire slipped out of my hand and hit the main lug. It just so happened I was lucky enough to drop the wire that was pinched to ground in the pancake mold. It only took 3 months for the burns to heel and the hair to grow back on my arm. But what the hell doctors need to make a living too.
DavidSeattle	I was tught to open a shorted circuit at half of its length , if that can be easily determined. In a string of lites that's no problem. Try to re-energize, If the circuit is oksy the problem is in the second half of the installation. Cut that in half and re-energize.Has the problem occured again. a simpler and safer method
marxlaws	quote: Originally posted by Romex Racer If you have 10 fluorescent fixtures wired together, like in a warehouse or something. If the ballast in one of those lights shorts out, it will trip the breaker and all the lights will go out. Now you have to open up every fixture, disconnect it and try the breaker to see which ballast is bad... A very time consuming job. Here's how to identify the bad fixture in seconds: Take the wire off the breaker and hold it against the bus. The bad fixture will be the one with the smoke and sparks flying out of it! In 27 years of wiring, I've done this a few times and it works every time! I know this isn't pretty, and some may blanch at the idea, but I learned this from an old hand who was the best electrician I've ever known. omg lol- thats rich i hope no 1st years read this answer. what if the short is a broken pipe in the wall? what if the ground is.. what if.. what if ...man, good luck with that.
renosteinke	I cannot endorse the idea of locating problems by bypassing the breaker. Period. Nor can I approve of a similar method used by some to identify circuits. I try to be a "no-spark" sparky! Here is a reasonably efficient way to fins a fault. First check the wires in the middle of the run; the fault is either to the left or the right. It would be a shame if you never used the continuity function on you meter, wouldn't it? Say the fauly is to the left...in this example, the left five fixtures. Put it all back together, and now 'split the difference' again. Now you know whether the fault is in either the first two fixtures, or fixtures 3,4,or 5. repeat the cycle. By 'splitting the difference,' you can run down the problem with a minimum of fuss. With the example of ten fixtures, you've run it down in no more than four tries. Don't have a meter? You ought to be calling an electrician anyway :-)
TOMWELDS	I usually have my helper reset the breaker and if i look at the fixtures carefully, i can see the 'good' fixtures turn on for a split second.
RS377	quote: Originally posted by DavidSeattle I was tught to open a shorted circuit at half of its length , if that can be easily determined. In a string of lites that's no problem. Try to re-energize, If the circuit is oksy the problem is in the second half of the installation. Cut that in half and re-energize.Has the problem occured again. a simpler and safer method This is the way I check everything, divide and conquer. Also, what happens if you trip the main breaker? I was working in a building putting 277 lights in, a single whip didn't get hooked up and shorted out when the breaker was flipped. Funny thing is, the main breaker for the entire five story building had a very sensitive GFCI (too sensitive, the factory came out and adjusted it later) and shut down the entire five story building, without tripping any other breaker in the building. RR's way seems way too sketchy
mtn man	not only is this practice dangerous it can damage equipment or cause the main breaker to trip I have seen a fault on a branch circuit trip the main service breaker and if you are in an industrial facility with a ground fault monitoring system you could trip the substation and take the entire facility down
Ryan_J	WOW!!! How did I miss the topic? I can't beleive I actually am reading this. Sounds like a marvelous way to get yourself hurt.
Celtic	This has got to be one of the most UNSAFE ideas I have ever heard...reminds of that joke/famous last words: " Watch this ! " ...usually followed by a trip to the ER. Why on earth would you put YOURSELF at risk to save a customer some money??? No offense RR - I have followed your posts on this board and a few others, and you seemed to have a handle on things - but are you nuts? What's the logic in putting yourself in harm's way?
Romex Racer	quote: Originally posted by Celtic This has got to be one of the most UNSAFE ideas I have ever heard... Dude, stick around, I have troubleshooting techniques that even I refuse to do. Maybe some day I'll tell you a cool way to test GFIs...
Celtic	quote: Originally posted by Romex Racer quote: Originally posted by Celtic This has got to be one of the most UNSAFE ideas I have ever heard... Dude, stick around, I have troubleshooting techniques that even I refuse to do. Maybe some day I'll tell you a cool way to test GFIs... But WHY? What's the point? Aren't we in business to MAKE money...and make it SAFELY? I hope your insurance premiums are paid, but I doubt the ins. co. will pay out on a claim from this sort of incident.
Romex Racer	Relax, I'm pulling your leg.
Celtic	quote: Originally posted by Romex Racer Relax, I'm pulling your leg. It took almost a year for the "punch line"?
baz	When I was an apprentice with the government, we often had to find a fault amongst rows of old flourescent fittings in old buildings with lots of office furniture in the way. A favorite technique was to pull out the fuse, wrap a new fuse wire round 3 or 4 times and stick it back in. Most effective when it's a shorted capacitor as it would scare the heck out of whoever was sitting under it. Consider the consequences of doing this on a main switchboard fed by a decent size transformer close by and you quickly realize how dangerous it is!!
kbsparky	Hey Baz! Welcome to the forum! I visited Australia 30 years ago, and remember those porcelian fuse holders and packages of fuse wire. Are they still widely in use today, or have circuit breakers become the normal standard? I also remember non-metallic sheathed cable being referred to as 3-036 I don't believe you folks were using AWG for sizing of your conductors or wires. I'd love to discover the differences in how your electrical installations are performed these days. Best regards, -Ken
baz	You haven't been allowed to use rewireable fuses on new installations since about 2001. Circuit breakers are now the norm. And it's not 3/036 anymore - it's 7/0.67, we've gone metric. The biggest change in Queensland is that they now only inspect a random 10% of all new installations. I haven't had a job inspected in years and there are tradesman around that have never had their work inspected. If you're thinking of coming over, come to Queensland, we're in an economic boom and don't have enough tradesman so there's plenty of good paying work.
kbsparky	Discussion continued here.