Type A, Type B, or Type C Decides Everything Else
One decision governs this entire category, and it is not length, wattage, or color. It is how the lamp gets its power: through the existing fluorescent ballast, directly from line voltage after the ballast is removed, or from a separate driver. Settle that first, because the wiring, the labor, the long-term maintenance, and the safety picture all follow from it. Where the fixtures themselves are grid-ceiling units under consideration for replacement, Lumera's troffers collection covers those.
How Type A, Type B, and Type C Differ in Practice
Type A is the fastest conversion of the three. The lamp runs on the fluorescent ballast that is already in the fixture, so an installer pulls the old tube, puts the new one in, and the job is finished with no rewiring at all. The cost of that speed is that the ballast stays in the circuit, still drawing its own losses and still able to fail, and when it does the new lamp goes dark with it. A Type A purchase also needs a check against the manufacturer's ballast compatibility sheet, because not every electronic ballast drives an LED load cleanly, and a mismatch usually announces itself as flicker.
Type B moves the fixture onto line voltage and takes the ballast out of the picture entirely, which means rewiring the fixture and removing or bypassing the ballast before the new lamp goes in. That is more labor at the front end, and it changes the fixture permanently, since the sockets now carry line voltage during relamping. It is also why Type B dominates larger retrofits, because once a crew is opening every fixture in a building anyway, leaving a component in place that will eventually fail makes little sense.
Type C replaces the ballast with a separate LED driver built for the lamp. It carries the highest installed cost of the three, since it needs both the rewiring and the driver itself, and it returns the best control in exchange, with real dimming and the steadiest output.
Some lamps are dual rated and will run either way, on a compatible ballast today and on direct wiring after the ballast is pulled later, which gives a building a staged path rather than a single decision. The product page states which type each lamp in this collection carries.
Ballast Bypass Carries a Real Safety Consideration
This part deserves plain language rather than a footnote. In a Type B conversion the fixture is wired so line voltage reaches the lamp sockets directly, which means the pins of a partially inserted lamp can be live.
There are two bypass wiring arrangements and they behave differently. Single-ended puts both line and neutral at one end of the lamp, so only one end is energized. Double-ended puts line at one end and neutral at the other, so both ends are involved. A lamp built for one arrangement is not automatically safe in the other, and mixing them is a genuine hazard rather than a compatibility annoyance.
The sockets matter too. Tombstones come shunted, with their two contacts joined internally, and non-shunted, with the contacts kept separate. Single-ended lamps need non-shunted sockets, and running the wrong combination can damage the lamp or the tombstone, so follow what the specific lamp's instructions call for and swap sockets where required.
Two habits protect everyone afterward. Wire exactly the arrangement the lamp specifies, and label the fixture after conversion so the next person to relamp it knows it is no longer a fluorescent fixture. That label is easy to skip and it is precisely what protects a maintenance worker years later. All of this is licensed electrician work rather than a lamp change.
T8, T5, T12, and the Base That Comes With Each
The T number is the tube diameter in eighths of an inch, so a T8 is one inch across and a T5 is five eighths. The difference matters because the lamp has to sit in the existing sockets and the fixture's reflector was shaped around a specific diameter.
T8 is by far the most common size in commercial buildings and is what most of this collection is built around. T5 and T5HO appear in newer and higher-output fixtures and use the smaller G5 base, so a T8 lamp will not fit a T5 socket.
T12 is the older, fatter tube found in aging installations, and it is the case worth flagging. T12 fixtures run magnetic ballasts that most ballast-compatible lamps do not work with, so a T12 conversion usually means a bypass or a new fixture outright. Where a building is old enough to still run T12, replacing the fixtures often costs less over the life of the installation than converting them.
Base follows diameter here: the T8 lamps use the G13 medium bi-pin and the T5 lamps the smaller G5, and the two do not interchange. Length is nominal rather than exact, so a four foot lamp is not precisely forty eight inches; measure the existing lamp or the socket spacing rather than assuming, particularly on older fixtures where odd lengths turn up.
Color Temperature, Output, and Consistency
Color temperature choice follows the space. Warmer settings suit hospitality and reception areas, neutral settings suit general office and classroom work, and cooler settings appear in industrial and detail-critical areas. Part of this range is selectable, with Euri's switchable models covering 3500K to 5000K and EnVision's tubular linears offering four settings, so the decision can be made at install rather than at order.
What generates complaints is consistency rather than the setting itself: mixing two color temperatures in one ceiling reads as a defect. Convert whole spaces at a time, and record the setting used on selectable lamps so a later replacement matches.
Dimming
Dimming behavior is tied directly to the type. Type A lamps generally do not dim, because the fluorescent ballast in the circuit was never built to dim an LED load. Type C is the type that dims properly, since it runs on a purpose-built driver with a real dimming input.
If the space needs dimming or an energy code calls for multi-level control, that pushes the specification toward Type C rather than the cheaper conversions. Lumera's ELV and 0-10V dimmers collection covers the controls those drivers accept.
When Replacing the Fixture Beats Converting It
A tube conversion keeps the existing housing, reflector, and lens, and that is both its advantage and its ceiling. An aging fixture with a yellowed lens, a dirty reflector, and a failing socket does not become a good fixture because the lamp inside it is new.
This collection acknowledges that case directly: the EnVision tubular linear fixtures stocked here are complete 2, 4, and 8 foot fixtures shaped like an oversized tube, a way to keep the look while retiring the old housing. Where a utility space needs a conventional replacement instead, Lumera's strip lights collection covers those fixtures.
For directional and reflector lamp shapes rather than tubes, Lumera's PAR lamps collection is the closer match.
And for the full lamp range across every base and shape, Lumera's LED bulbs and lamps collection is the place to browse.
LED Tube Lamp FAQs
What is the difference between Type A, Type B, and Type C tubes?
Type A runs on the existing fluorescent ballast, so it is a lamp swap with no rewiring. Type B runs on line voltage with the ballast removed, which takes more labor but eliminates the ballast as a failure point. Type C uses a separate LED driver in place of the ballast and gives the best dimming and performance. The product page states which type a given lamp carries.
Is ballast bypass safe?
It is standard practice when done correctly, and it carries a real consideration. In a bypass fixture the lamp pins can be at line voltage, so use the wiring arrangement the specific lamp requires, single-ended or double-ended, match the sockets to it, and label the fixture after conversion so the next person relamping it knows it is no longer fluorescent. This is licensed electrician work.
Can I put an LED tube in a T12 fixture?
Usually not as a simple swap. T12 fixtures use magnetic ballasts that most ballast-compatible lamps will not run on, so a conversion generally means a bypass or a new fixture. Given the age of most T12 installations, replacing the fixture is often the better value.
How do I know if I have T8 or T5?
The number is the diameter in eighths of an inch, so a T8 is one inch across and a T5 is five eighths. They also use different bases, G13 on T8 and G5 on T5, so the lamps do not interchange. Measure the existing tube rather than guessing from the fixture's age.
Do LED tubes dim?
It depends on the type. Type A generally does not, because the fluorescent ballast in the circuit was never designed to dim an LED load. Type C dims properly through its own driver. If dimming or multi-level control is required, that requirement decides the type.
Is it better to convert the fixture or replace it?
Convert when the housing, reflector, and lens are in good condition. Replace when the fixture is old, the optics are degraded, or the space needs controls the existing housing cannot support, since a new lamp in a tired fixture still gives you a tired fixture.
