A fluorescent lamp luminaire contains one or more lamps, lampholder and ballast, as well as the wiring between the various parts. Some older types also have the so-called "starter". The ballast is a device that has the purpose of turning on the lamp and regulating the flow of the electric current that passes through it. In case of failure, the ballast must be replaced. This article explains how to replace the ballast with a new, certified and compatible one. Read the article all the way through, including the warnings section, before you get down to business.
Steps
Step 1. Before attempting to replace the ballast, check if the malfunction is actually caused by a faulty ballast
First, try replacing the lamp with a known good one. When a lamp (or tube) appears blackened at one or both ends, it is usually out of order, but the only way to be sure is to replace it with a working one. Remember that fluorescent lamps rarely fail suddenly - they generally decay progressively. If all the fluorescent tubes of the same luminaire stop working at the same time, the problem probably does not lie with the tubes. If the replacement of the tubes does not solve the problem, and if the luminaire has one or more "starters" (usually found in rather dated systems), try to replace the starter. Each lamp or tube has its own starter. The starter is a small component (typically 20 mm in diameter by 30 mm in length), inserted into the circuit through a special connector that is usually found at one end of the lighting body or behind a lamp. The starters are very cheap (you can also find them for less than € 0.5). It is not easy to determine if a starter has failed by visual inspection alone. To be sure that the origin of the malfunction comes from a faulty starter, try replacing it with a new one or one that is known to be "good". If replacing the tubes and starters does not solve the problem, the most likely cause is a failure of the ballast.
Step 2. Remove the lamps and set them aside in a safe place
Step 3. Disconnect the power from the system by opening the local circuit breaker and also the main switch, which is located in the control box
If you are not sure which switch controls the section of the system in which your lamp is located, for safety, completely cut the power to the whole house by opening all the switches on the panel. Rotate the fixing tabs located near the center of the light fixture by ninety degrees. They should come off on their own. Remove them and set them aside. Do the same on the other end.
Step 4. Before cutting the connection cables, check that the two power cables, the phase and the neutral, are not under voltage with respect to earth (so it should be, since you have interrupted the electrical circuit upstream, but it is better be sure)
The presence of voltage can be verified with a simple voltmeter or other indicator instrument. Also consider the alternative method of cutting the wires described in step 11. Locate the ballast and follow the wires to the connection terminals (usually wires of the same color should be connected together: blue with blue etc.). If there are no clamps you have to cut the wires about 30 cm from the center of the luminaire on both sides. Continue this operation until all wires are cut or disconnected from the terminals.
Step 5. Unscrew the nut that fixes the ballast to the luminaire, holding it still with the other hand
It is advisable to use a wrench suitable for bolts and nuts, or a socket wrench. Remove the ballast by lowering the side held by the nut, and sliding it off in that direction.
Step 6. Take the ballast with you to the electrical supply store to purchase an equivalent replacement
Take note of the number of tubes in the luminaire with their characteristics: power, length, type (T8, T12, T5 etc.). Also note that in a four-tube luminaire there might be two ballasts, one for a pair of tubes and one for the other.
Step 7. Install the spare ballast by reversing the sequence of operations of step 5
Make sure you restore the electrical connections correctly: blue wire with blue, red with red, green / yellow with green / yellow.
Step 8. If you have decided to cut the wires, cut them to such a length that they can overlap the ones left in the luminaire for about 15 cm
Step 9. Strip the ends of all 8 wires; remove the insulation so that a section of conductor about 12 mm long is exposed
Step 10. Use a mammoth or other type of clamp for electrical cables and connect the wires of the ballast with those of the luminaire respecting the correspondence of the colors
If you want to avoid cutting and joining the wires, there is an alternative method: extract the original wires from the lamp holder, and then connect the ones coming out of the ballast in their place. To extract existing threads, remove them by twisting and pulling gently. Twist the wires a little back and forth, like when using a screwdriver; it doesn't take much but it is essential, otherwise the wires will hardly come off. As you remove them, take note of the color of the strands you pull out and their location. To connect the new ballast, simply thread each wire into the hole you pulled the old one from and pull the wire lightly to secure it in place (this is the same method used at the factory).
Step 11. Repeat step 3 backwards
Make sure that the fixing tabs are well inserted into the light fixture.
Step 12. Put the (new) lamps back
Step 13. Turn on the light
Advice
- This is an excellent opportunity to clean up the luminaire.
- If you buy a new type of ballast, you will have two blue wires and two brown wires. But probably a single brown wire will come out of only one tube of the lamp holder in your luminaire. The other wire is neutral (blue). Cut the blue wire away from the socket. The two brown wires go from the ballast to the lamp holder which is at one end of the tube and the two blue wires at the other end. The phase wire of the 220V (brown) and the neutral (blue) go ONLY to the electronic ballast. If you connect one of the brown wires to a neutral (blue) you will irreparably damage the ballast.
- Sometimes a lamp does not turn on completely. The causes of partial ignition can be, in order: the ambient temperature or the lamp itself is too cold, the lamp or starter is faulty, the ballast connections on the 220 side are reversed, the lamp holders are faulty, the ballast is broken. Certain types of lighting fixtures may need to be properly grounded.
- The lamp may take more than a minute to turn on completely.
Warnings
- When carrying out any work on the electrical system you must: wear shoes with insulating soles, stand on a piece of wood or use a wooden ladder. As you work, you should avoid touching conductive surfaces or leaning towards them. If you are not sure if the implant is under tension, you must work with one hand, keeping the other in your pocket. Use a voltmeter or preferably a voltage gauge to check for the presence or absence of voltage to ground for all wires (of any color) in the system or circuit.
- When purchasing the replacement ballast, choose one that has the same part number as the old one, or an equivalent one based on parameters such as "type" (electronic or electromagnetic technology), input voltage, number and type of lamps, power and, if you wish, silence. In addition, both electromagnetic and electronic ballasts are available in “quick start” (or “controlled”) or “instant start” versions. The choice can be guided by the type of use of the lighting body: for example, if the light usually stays on for 10 or more hours in a row, choose instantaneous ignition because it is a little more efficient but if the light is switched on and turned off frequently then it is better to use the controlled ignition for a longer life of the lamps and the ballast.
- If you replace a new electronic ballast with an old electromagnetic model, it may be that the new ballast requires the use of the new energy efficient lamps, and the possible replacement of the lamp holder with one suitable for the contacts of the new lamps. The old lampholders may not be compatible with the new lamps, and on the other hand the new ballast may not be able to drive old model lamps. Given the commitment in terms of time and money required by such an operation, it may be advisable to install one of the same technology in place of the faulty ballast, or to replace the entire lighting body as a whole.
- If you choose the path of changing technology, you should be able to correctly interpret an electrical diagram. The connection diagram of an electronic ballast is different from that of the old electromagnetic ballast and must be followed faithfully. Check the type of lamp supported by the ballast (most likely it will be the T-8 type) and get the correct lamp holders. If you need to add connecting sections between the ballast and the lamp holders, make sure to use electrical cables of the same section and with the same type of insulation as the wires coming out of the ballast, to avoid possible overheating and consequent fire risk. Any connection terminals must be chosen taking into account the section and the number of cables to be connected together.
- Properly recycle used fluorescent lamps. All fluorescent lamps contain mercury (also the so-called types marked as "ecological"). Handle them carefully to prevent them from breaking.
- A luminaire with fluorescent lamps must never come into contact with combustible materials, due to the heat generated by the ballast. Leave a safety distance of at least 25 mm between the lighting body and any combustible materials to reduce the risk of fire.
