The Fluorescent Lighting System

Make sure all power control switches are turned on.

If this fixture has starters, check the other causes.

Lamps and starters have been known to vibrate or be bumped so that they no longer make electrical contact.

Starters turn clockwise to lock into their sockets, while lamps have an alignment mark on each end of the lamp (usually a depression in the metal cap) that indicates where the tube should be positioned when installed.

If the fixture has more than one lamp, it is unlikely that all lamps and starters came loose at the same time, so check the other causes.

If the fixture has more than one lamp that isn't working, it is unlikely that all lamps and starters failed at the same time, so check the other causes.

If the fixture has multiple ballast's and none of the lamps work, the problem is almost certainly a lack of electricity or low supply voltage. Use an AC voltmeter to verify that the right electrical voltage is reaching the ballast. Do not measure at the lamp sockets or starter socket. The correct voltage for the ballast should be marked on the ballast.

However, if a fixture was recently installed or repaired and hasn't worked since, you may have a wiring error that is causing the problem. A schematic showing the correct wiring is present on almost all ballast's, so compare the wiring of the fixture to that drawing.

It is also possible that rodents have damaged wiring or that wiring has been crushed or worn within the fixture, causing a short. Look for any places where the wiring has been caught by the metal parts of the fixture and replace any damaged wiring with wire of the same gauge and insulation temperature.

High-temperature electrical tape can be used to cover worn insulation, so long as the wire itself isn't damaged.

In addition, when a ballast is malfunctioning and overheats, a safety thermal protector inside the ballast can cause the ballast to abruptly turn off (sometimes with an audible "click" or "ping" sound) and all lamps connected to that ballast will go dark. After several minutes when the ballast has had time to cool-down, the ballast turns back on and the lamps come back on at full brightness and may operate for a period of several minutes before shutting off again. This cycle will repeat endlessly until the problem is corrected, although the cycle may get slightly shorter when the fixture is left on for hours. If you see or hear this condition, replace the ballast and the lamps and the starters that connect to that ballast. Ballast's that are overheating like this are probably also leaking, so watch out for any hot tar that may spill out of an overhead fixture when you are working on it.

(If the lamps flicker and blink on and off several times in just a few minutes or seconds, this is probably just a bad lamp(s) or starter(s), not a bad ballast. Replace all lamps and starters connected to the ballast and see if the problem persists before replacing the ballast. If the ballast is faulty, the problem should reappear in an hour or so.)

For example, if a ballast is rated for 120VAC, it probably won't work properly if the line voltage is below 108VAC. Other devices in the typical business or residence would not work well if the voltage was so far off. Being 2% off (117VAC instead of 120VAC) probably won't hurt.

If you find that the line voltage is too low, contact the power company or an electrician to investigate the problem.

If the ends of the lamp are constantly lit with no blinking or flickering, it usually indicates that the starter has gotten stuck in the "start" position. Replace the starter. Note that when this happens, it can greatly reduce the life of the lamp. When the fixture is turned off, if the ends of the lamp appear dark or "smoky" in color, the lamp should be replaced as well.

This behavior may be repeated each time the lamp is turned on for the first 20 to 30 hours of use. After this aging period, this behavior doesn't occur or only takes a minute or so to obtain full brightness across the entire tube.

The only action that could be taken would be to leave brand new lamps on for ten to twenty hours to break them in. Otherwise, ignore this artifact.

If the air temperature is considerably colder and if the surrounding air is circulating, the lamps will never generate enough heat to keep their internal temperatures above 50F, so the lamps will continue to glow dimly and flicker.

The solution here are to use enclosed fixtures that provide insulation from colder air temperatures by trapping a limited amount of air around the lamps. When the lamps are operating, the lamps are insulated from a constant fresh supply of cold air, and gradually the air inside the fixture will heat along with the lamps and the lamps will start to operate normally.

In cases where it is not desired to replace the entire fixture, there are plastic lamp sleeves available. The lamp is inserted into these sleeves and a plastic cap on each end seals the lamp inside the plastic tube, allowing only the electrical contacts of the lamp to protrude. This entire assembly is then placed in the socket in the light fixture. Such sleeves are commonly seen on fluorescent lamps in grocery store freezer units, or in outdoor fluorescent lighting used in commercial locations such as the front porch area of stores.

Fixtures that use the High-Output lamps (HO) are typically found in outdoor signs and other locations where exposure to cold temperatures is expected. These lamps provide most of their brightness down to 10F. They can also be protected to operate at even lower temperatures by using enclosed fixtures or lamp sleeves.

"Feathers" cause no harm and do not indicate that a lamp is bad or worn out.

This is a normal part of lamp aging, and should be ignored until the lamp eventually fails to start. This aging should be gradual, as the typical fluorescent lamp has at least 10,000 hours of operating life. When the lamp does finally wear out, the discoloration on the end of the lamps can be as dark as coal.

The only case where this would be considered a problem would be if new lamps develop these marks within the first 100 hours of use and have trouble starting. That may indicate that the starter was not replaced, the wrong size starter was used, or the ballast is faulty or the wrong type.

Make sure all power control switches are turned on.

Lamps have been known to vibrate or be bumped so that they no longer make electrical contact.

Lamps have an alignment mark on each end of the lamp (usually a depression in the metal or plastic end caps) that indicates where the tube should be positioned when installed.

If the fixture has more than one lamp, it is unlikely that all lamps came loose at the same time, so check the other causes.

If the fixture has more than two lamps that aren't working, it is unlikely that all lamps failed at the same time, so check the other causes.

If the fixture has multiple ballast's and none of the lamps work, the problem is almost certainly a lack of electricity or low supply voltage. Use an AC voltmeter to verify that the right electrical voltage is reaching the ballast. Do not measure at the lamp sockets. The correct voltage for the ballast should be marked on the ballast.

However, if a fixture was recently installed or repaired and hasn't worked since, you may have a wiring error that is causing the problem. A schematic showing the correct wiring is present on almost all ballast's, so compare the wiring of the fixture to that drawing.

It is also possible that rodents have damaged wiring or that wiring has been crushed or worn within the fixture, causing a short. Look for any places where the wiring has been caught by the metal parts of the fixture and replace any damaged wiring with wire of the same gauge and insulation temperature.

High-temperature electrical tape can be used to cover worn insulation, so long as the wire itself isn't damaged.

In addition, when a ballast is malfunctioning and overheats, a safety thermal protector inside the ballast can cause the ballast to abruptly turn off (sometimes with an audible "click" or "ping" sound) and all lamps connected to that ballast will go dark. After several minutes when the ballast has had time to cool-down, the ballast turns back on and the lamps come back on at full brightness and may operate for a period of several minutes before shutting off again. This cycle will repeat endlessly until the problem is corrected, although the cycle may get slightly shorter when the fixture is left on for hours. If you see or hear this condition, replace the ballast and the lamps that connect to that ballast. Ballast's that are overheating like this are probably also leaking, so watch out for any hot tar that may spill out of an overhead fixture when you are working on it.

(If the lamps flicker and blink on and off several times in just a few minutes or seconds, this is probably just a bad lamp or lamps. not a bad ballast. Replace all lamps connected to the ballast and see if the problem persists before replacing the ballast. If the ballast is faulty, the problem should reappear in an hour or so.)

For example, if a ballast is rated for 120VAC, it probably won't work properly if the line voltage is below 108VAC. Other devices in the typical business or residence would not work well if the voltage was so far off. Being 2% off (117VAC instead of 120VAC) probably won't hurt.

If you find that the line voltage is too low, contact the power company or an electrician to investigate the problem.

This behavior may be repeated each time the lamp is turned on for the first 20 to 30 hours of use. After this aging period, this behavior doesn't occur or only takes a minute or so to obtain full brightness across the entire tube.

The only action that could be taken would be to leave brand new lamps on for ten to twenty hours to break them in. Otherwise, ignore this artifact.

Verify that both ends of all lamps are correctly inserted into each socket and that the lamp is rotated to the the correct position. This is indicated on the end-cap of the lamp as a ridge or indentation that should align with the slot in the end of the socket.

The lamp or lamps that are not installed in the socket correctly can be any of the lamps, including one of the ones glowing dimly. Check all lamps.

A fixture that has a power cord is grounded through the ground prong on the power plug. In North America, the round prong is ground. Some older buildings have outlets that do not have grounded outlets (sometimes called two-prong outlets instead of three-prong), and a three-prong cord can be plugged-in only by use of a "cheater" adapter. These "cheaters" do not provide a ground, and this can make a fluorescent fixture malfunction that is connected to them. Have a proper grounded outlet installed for use with the fluorescent fixture.

For fixtures that are wired permanently to the buildings electrical system, a ground wire should have been provided as part of the building wiring. In some older commercial buildings, the metal conduit served as the ground, but newer electrical codes require a ground wire to be installed, even when metal conduit is used. If the fixture is permanently installed and the building wiring lacks a proper ground, have a ground installed for locations that need them.

The most likely cause of a fixture grounding problem that suddenly occurs is in the fixture itself, because fixture designs usually rely on clips, screws or other metal fasteners to force electrical contact between the metal reflector and the ballast. This grounding can be defeated if these parts are missing, or if the fixture or replacement parts have been re-painted in such a way that the metal parts now can't make good electrical contact. Always ensure that all fasteners that came with the fixture are re-installed after servicing. When replacing a ballast, use a piece of sandpaper to scratch the paint off the ballast case at the points where the ballast makes contact with the metal fixture. This will help ensure that the ballast is making good electrical contact with the rest of the fixture.

The ground wire from the ballast (normally green in color) must be connected to the electrical supply ground wire, and in some fixtures, a special terminal is provided on the fixture to tie the ballast and supply ground wires together while also making a solid electrical contact with the fixture. Such grounding points may employ a green-colored screw to distinguish them from screws and other hardware meant to mount the fixture.

For example, if a ballast is rated for 120VAC, it probably won't work properly if the line voltage is below 108VAC. Other devices in the typical business or residence would not work well if the voltage was so far off. Being 2% off (117VAC instead of 120VAC) probably won't hurt.

If you find that the line voltage is too low, contact the power company or an electrician to investigate the problem.

If the air temperature is considerably colder and if the surrounding air is circulating, the lamps will never generate enough heat to keep their internal temperatures above 50F, so the lamps will continue to glow dimly and flicker.

The solution here are to use enclosed fixtures that provide insulation from colder air temperatures by trapping a limited amount of air around the lamps. When the lamps are operating, the lamps are insulated from a constant fresh supply of cold air, and gradually the air inside the fixture will heat along with the lamps and the lamps will start to operate normally.

In cases where it is not desired to replace the entire fixture, there are plastic lamp sleeves available. The lamp is inserted into these sleeves and a plastic cap on each end seals the lamp inside the plastic tube, allowing only the electrical contacts of the lamp to protrude. This entire assembly is then placed in the socket in the light fixture. Such sleeves are commonly seen on fluorescent lamps in grocery store freezer units, or in outdoor fluorescent lighting used in commercial locations such as the front porch area of stores.

Fixtures that use the High-Output lamps (HO) are typically found in outdoor signs and other locations where exposure to cold temperatures is expected. These lamps provide most of their brightness down to 10F. They can also be protected to operate at even lower temperatures by using enclosed fixtures or lamp sleeves.

"Feathers" cause no harm and do not indicate that a lamp is bad or worn out.

This is a normal part of lamp aging, and should be ignored until the lamp eventually fails to start. This aging should be gradual, as the typical fluorescent lamp has at least 10,000 hours of operating life. When the lamp does finally wear out, the discoloration on the end of the lamps can be as dark as coal.

The only case where this would be considered a problem would be if new lamps develop these marks within the first 100 hours of use and have trouble starting. That may indicate that the starter was not replaced, the wrong size starter was used, the ballast is faulty or the wrong type, or the fixture and ballast are not properly grounded.

Make sure all power control switches are turned on.

Some instant start fixtures utilize "disconnect" sockets. If any lamps are missing or not fully inserted into both lamp sockets, power to part or all of the entire fixture may be disconnected. Check that all lamps are fully seated.

Lamps have been known to vibrate or be bumped so that they no longer make electrical contact.

Lamps have an alignment mark on each end of the lamp (usually a depression in the metal or plastic end caps) that indicates where the tube should be positioned when installed.

If the fixture has more than one lamp, it is unlikely that all lamps came loose at the same time, so check the other causes.

If the fixture has more than two lamps that aren't working, it is unlikely that all lamps failed at the same time, so check the other causes.

If the fixture has multiple ballast's and none of the lamps work, the problem is almost certainly a lack of electricity or low supply voltage. Use an AC voltmeter to verify that the right electrical voltage is reaching the ballast. Do not measure at the lamp sockets. The correct voltage for the ballast should be marked on the ballast.

However, if a fixture was recently installed or repaired and hasn't worked since, you may have a wiring error that is causing the problem. A schematic showing the correct wiring is present on almost all ballast's, so compare the wiring of the fixture to that drawing.

It is also possible that rodents have damaged wiring or that wiring has been crushed or worn within the fixture, causing a short. Look for any places where the wiring has been caught by the metal parts of the fixture and replace any damaged wiring with wire of the same gauge and insulation temperature.

High-temperature electrical tape can be used to cover worn insulation, so long as the wire itself isn't damaged.

In addition, when a ballast is malfunctioning and overheats, a safety thermal protector inside the ballast can cause the ballast to abruptly turn off (sometimes with an audible "click" or "ping" sound) and all lamps connected to that ballast will go dark. After several minutes when the ballast has had time to cool-down, the ballast turns back on and the lamps come back on at full brightness and may operate for a period of several minutes before shutting off again. This cycle will repeat endlessly until the problem is corrected, although the cycle may get slightly shorter when the fixture is left on for hours. If you see or hear this condition, replace the ballast and the lamps that connect to that ballast. Ballast's that are overheating like this are probably also leaking, so watch out for any hot tar that may spill out of an overhead fixture when you are working on it.

(If the lamps flicker and blink on and off several times in just a few minutes or seconds, this is probably just a bad lamp or lamps. not a bad ballast. Replace all lamps connected to the ballast and see if the problem persists before replacing the ballast. If the ballast is faulty, the problem should reappear in an hour or so.)

For example, if a ballast is rated for 120VAC, it probably won't work properly if the line voltage is below 108VAC. Other devices in the typical business or residence would not work well if the voltage was so far off. Being 2% off (117VAC instead of 120VAC) probably won't hurt.

If you find that the line voltage is too low, contact the power company or an electrician to investigate the problem.

This behavior may be repeated each time the lamp is turned on for the first 20 to 30 hours of use. After this aging period, this behavior doesn't occur or only takes a minute or so to obtain full brightness across the entire tube.

The only action that could be taken would be to leave brand new lamps on for ten to twenty hours to break them in. Otherwise, ignore this artifact.

If the air temperature is considerably colder and if the surrounding air is circulating, the lamps will never generate enough heat to keep their internal temperatures above 50F, so the lamps will continue to glow dimly and flicker.

The solution here are to use enclosed fixtures that provide insulation from colder air temperatures by trapping a limited amount of air around the lamps. When the lamps are operating, the lamps are insulated from a constant fresh supply of cold air, and gradually the air inside the fixture will heat along with the lamps and the lamps will start to operate normally.

In cases where it is not desired to replace the entire fixture, there are plastic lamp sleeves available. The lamp is inserted into these sleeves and a plastic cap on each end seals the lamp inside the plastic tube, allowing only the electrical contacts of the lamp to protrude. This entire assembly is then placed in the socket in the light fixture. Such sleeves are commonly seen on fluorescent lamps in grocery store freezer units, or in outdoor fluorescent lighting used in commercial locations such as the front porch area of stores.

Fixtures that use the High-Output lamps (HO) are typically found in outdoor signs and other locations where exposure to cold temperatures is expected. These lamps provide most of their brightness down to 10F. They can also be protected to operate at even lower temperatures by using enclosed fixtures or lamp sleeves.

"Feathers" cause no harm and do not indicate that a lamp is bad or worn out.

This is a normal part of lamp aging, and should be ignored until the lamp eventually fails to start. This aging should be gradual, as the typical fluorescent lamp has at least 10,000 hours of operating life. When the lamp does finally wear out, the discoloration on the end of the lamps can be as dark as coal.

The only case where this would be considered a problem would be if new lamps develop these marks within the first 100 hours of use and have trouble starting. That may indicate that the starter was not replaced, the wrong size starter was used, the ballast is faulty or the wrong type, or the fixture and ballast are not properly grounded.

Alternatively, hardware stores sell a lamp socket "extender", a device roughly two inches in length and it consists of a lamp socket and a lamp screw base. This is inserted into the existing socket, then the lamp is inserted into the extender. This gets the lamp assembly further away from the base of the fixture, but it may also make the lamp extend out of the fixture.

Also, some photocell and timer controls don't use a relay or electrical contact to turn and off the power. Instead, they use a solid state electronic component - usually a triac - to control the power flow. Unfortunately, triacs don't allow 100% of the electricity to flow through when they are conducting, and this can interfere with the electronics in the compact fluorescent lamp base. If the compact fluorescent lamp works correctly in another socket that is controlled from a wall switch, this could be the problem.

Also, some photocell and timer controls don't use a relay or electrical contact to turn and off the power. Instead, they use a solid state electronic component - usually a triac - to control the power flow. Unfortunately, triacs don't allow 100% of the electricity to flow through when they are conducting, and this can interfere with the electronics in the compact fluorescent lamp base. If the compact fluorescent lamp works correctly in another socket that is controlled from a wall switch, this could be the problem.

If the air temperature is considerably colder and if the surrounding air is circulating, the lamps will never generate enough heat to keep their internal temperatures above 50F, so the lamps will continue to glow dimly and flicker.

The solution is to use compact fluorescent lamps designed for outdoor or cold locations, or use an enclosed fixture. Note that some compact fluorescent lamps cannot be used in outdoor, in damp locations, or in enclosed fixtures, so check the specifications or use instructions that come with the lamp.

"Feathers" cause no harm and do not indicate that a lamp is bad or worn out.

This is a normal part of lamp aging, and should be ignored until the lamp eventually fails to start. This aging should be gradual, as the typical fluorescent lamp has at least 10,000 hours of operating life. When the lamp does finally wear out, the discoloration on the end of the lamps can be as dark as coal.

The only case where this would be considered a problem would be if new lamps develop these marks within the first 100 hours of use and have trouble starting. This may indicate a low or high voltage power problem in the socket or a faulty lamp assembly.