In my previous post, I showed the way to hook up a simple fluorescent light. That’s good for a new light. What if you have an existing fluorescent light that refuse to light up? It’s very easy to detect the faulty part.
Is the florescent tube blinking or flickering?
If it is, there is a 90% chance that you have a faulty florescent tube. Just twist out the tube and replace it with a new one.
Both ends of the tube are glowing red.
Then the fault is with the starter. The starter acts like a booster to kick start the light. It will weaken over a certain period. Change the starter.
Nothing happens when I switch the light on.
Now this will take some fault finding. If you know how to use a AVO meter, you can remove the light’s cover and locate the ballast. On the two terminals of the ballast, check for continuity with your meter, but I think most household don’t keep this kind of meter at home, as it is an electrician’s tool. So the next best way is to use a test pen.
Using a test pen to determine the state of the ballast is easy, but you have to be careful as it can only be done with the lights switched on. First of all before you do anything, use your test pen to determine if the lights casing can light up the test pen. Make sure you DON’T touch the light with your bare hands. A lot of half past six electricians don’t “earth” the fluorescent lights, so even though there is a leakage, the lights still works but the casing of the lights will be “alive” as well. If the casing is properly earthed, you won’t have to to that because whenever there is a leakage, your Circuit Breaker located at your Main Panel will trip off automatically.
Like I said in the previous post, the live wires should be terminated at the ballast. So at least one terminal of the ballast should light up the test pen. Put you test pen on any one of the terminals to check if electrical supply is present. If there is supply to one terminal, and there is NO supply to the one beside it, then the ballast is faulty. If this is the case, then you switch off the current and replace the ballast. But, if there is no electricity supply to both the terminals, then the reason might be something else.
For the time being, 80% of all faulty florescent lights are due to these 3 faults. The starter, the Tube and the Ballast.
In my following post, I will show how to use the simple test pen to check for the presence of electricity and what to do if all these 3 faults have been taken care of
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[...] that you have done all the 3 basic steps when checking for a faulty light and you fail to repair that light because there is no electricity supply going to the light itself. [...]
ive got a twin florecent light with one ballast. both of the tubes stopped showing. i fitted new tubes , starters and ballast and still not working.
can you help!!!!!
whnthtat is meant by earthing the fluroscent ligth
Nick,
To earth the florescent light means there should be an earth wire tied up securely onto any part of the light’s metal casing. In case there is an electrical leakage somewhere within the light and if the metal casing has not been “earthed” then someone who touches the metal casing with his bare hands will be electrocuted.
If there is an earth wire, (normally green in color) tied to the casing, the excess current will travel through the earth wire to the earth rod which is planted into the ground and which you will find outside your house. The excess current will also trigger the Circuit breaker to cut of current immediately when there is a leakage, so no-one will get hurt.
I just discovered this site –Hope it will have some useful comments —–as of now I have a florescent light with two bulbs two starters and to ballasts /transformers that don’t work.can you help Thanks Jerry
Jerry
Hi,
A twin tube florescent works exactly like a single tube one except it has 2 or everything which in fact is 2 lights combined into one.
I presume that you have one light that is not working? or are both the lights not working altogether?
If only one part is not working, you can first interchange the working tube with the non working one. If that works, then the tube is faulty.
If that doesn’t work, try interchanging the starters as well. If that still doesn’t work, interchange the ballast. Just remove the wires and fix it back exactly the way you removed it.
Go step by step as these are the main culprits.
The next culprit could be the tube holders. When you twist your tube in, it should lock in place with a clicking sound. If you feel the holders are not holding the tubes strongly, this might be the problem. Twist it a few times to see whether it lights up.
If all doesn’t work, you will have to check the wirings to see if there are any breakage. Follow each wire to their terminals and check if any one terminal has loosened by giving it a slight pull.
However if both the lights are not working together at the same time, there might be something wrong with your switch or the wires running to the light.
Hope that clears up a bit for you, but sometimes checking for faults in florescent lights can be quite daunting. There are many unforseen circumstances and most of the time, I advise my customers to simply replace the whole set rather than waste time and money on labor charges to check for faults.
I found you from google and the information in your page is really useful.
Just want to know whether the cause of power trip after I switch on the lights of my daughters room after a few hours is due to faulty ballast. I know its the light from the room that caused the trip, as after the power trip i isolated the problem to the light switch.
The switch controls four separate PLC light bulbs casing. It is a hassle to open up the casing to get access (8 allen key screws) per casing so I just want to be sure before I do the 3 steps you describe.
Thanks a lot..and it great that you share your knowledge with the rest.