How to Wire LED Tube Lights Without a Ballast: Single-Ended and Double-Ended Bypass

Replacing fluorescent tubes with LED tubes is one of the simplest lighting upgrades. Ballast-bypass tubes, which run directly on mains voltage, remove the ballast from the circuit, saving energy and eliminating ballast failures. They need the fixture to be rewired correctly. This guide explains how, and what to check.

Safety note: mains wiring is dangerous and in many places must be done by a licensed electrician. Isolate the circuit and confirm it is dead before opening a fixture. Always follow the tube maker’s wiring diagram; it overrides any general guide.

Types of LED tube

• Type A (plug-and-play): runs on the existing fluorescent ballast; no rewiring, but relies on the ballast
• Type B (ballast bypass / direct wire): runs directly on mains; ballast removed
• Type A+B (hybrid): works either way
• Type C: uses a separate remote LED driver

This guide covers Type B. For a comparison of all options, see LED fluorescent tube replacement.

Single-ended vs double-ended

Single-ended: live and neutral connect to the two pins at one end of the tube. The other end has no electrical connection and only holds the tube. The powered end is usually marked on the tube.

Double-ended: live connects to one end, neutral to the other. Each end’s two pins are usually joined internally.

Check the tube label. Mixing up the wiring can cause a short circuit or a dead tube.

Shunted and non-shunted lampholders

Lampholders (“tombstones”) come in two kinds:

• Shunted: the two contacts are connected inside, so both pins of the tube are on one conductor. Common with instant-start fluorescent ballasts.
• Non-shunted: the two contacts are separate, each with its own wire.

For single-ended tubes, the powered end needs non-shunted lampholders, so live and neutral reach different pins. Using a shunted holder here connects live directly to neutral through the holder.

For double-ended tubes, shunted or non-shunted holders usually work, as specified by the maker.

To identify the type, check the markings, look at the number of wire entries, or test continuity between the two contacts with the power off.

Step-by-step: single-ended bypass

1. Isolate the circuit at the breaker and test that the fixture is dead
2. Remove tubes and the fixture’s cover to expose the ballast
3. Cut the wires from the ballast to the lampholders and from the supply to the ballast; remove the ballast or leave it disconnected and secured
4. Replace lampholders at the powered end with non-shunted types if needed
5. Connect live to one contact and neutral to the other contact of the powered-end holder, for each tube position as specified
6. Leave the other end’s holders unconnected (they only support the tube)
7. Earth the fixture body as before
8. Fit the label supplied with the tubes stating that the fixture is now for LED tubes only and showing the wiring
9. Fit tubes with the powered end at the wired holders, restore power and test

Step-by-step: double-ended bypass

1. Isolate and test dead
2. Remove ballast connections as above
3. Connect live to the lampholders at one end of the fixture
4. Connect neutral to the lampholders at the other end
5. Earth the fixture
6. Label the fixture for LED tubes only
7. Fit tubes, restore power and test

Labelling

Labelling is essential. A fixture rewired for bypass tubes can no longer take fluorescent tubes; fitting one could be dangerous. Most bypass tubes come with labels stating the type of tube the fixture now requires and the wiring. Fix the label inside the fixture where it will be seen at relamping.

Common mistakes

• Using shunted lampholders with single-ended tubes
• Fitting single-ended tubes the wrong way round
• Leaving the ballast connected in a bypass installation
• Forgetting to label the fixture
• Mixing tube types in one fixture
• Poor connections in old, brittle lampholders; replace them if they crack

Is bypass the right choice?

Advantages:

• No ballast to fail
• Lower energy use than plug-and-play
• Long-term simplicity

Disadvantages:

• Labour to rewire each fixture
• Fixture is permanently converted
• Requires qualified work in many places

In old, yellowed or damaged fixtures, replacing the whole fitting with an integrated LED batten or panel can cost little more than rewiring and gives a better result. See LED tube strip lights and LED flat panel lights.

Choosing tubes

• Check the type (B, single- or double-ended)
• Lumens per tube (about 1,800–2,400 lm for 4 ft T8)
• Colour temperature to match the space; see fluorescent tube colour temperature
• Certification for your market
• Flicker-free driver

Our LED T8 tube is available in common lengths; ask us to confirm the wiring type for your fixtures.

Testing after conversion

After rewiring, check each fixture lights correctly, that tubes are secure in their holders, that the fixture is earthed, and that the circuit protection is unchanged. In larger buildings, record which fixtures have been converted, so maintenance staff buy the right tubes in future.

Energy savings

A typical 2 × 36 W fluorescent fixture with ballast draws about 70–80 W. Two 18 W LED bypass tubes draw about 36 W. The LED retrofit savings calculator estimates the savings for your building.

For larger projects

Schools, offices and warehouses with hundreds of fluorescent fittings benefit from planning: survey fixture types, decide between tubes and new fittings, and convert by area. Send us your fixture list and we will suggest tubes or replacement fittings.