Upgrade Your Lighting: Step-by-Step Guide to Bypassing a Ballast

Understanding the Ballast Bypass (Type B) Retrofit

In commercial and industrial environments, the "Ballast Bypass" (also known as a Type B retrofit) is the preferred method for converting fluorescent fixtures to LED. By removing the ballast, facility managers eliminate a common failure point and reduce energy consumption. This guide outlines the professional procedure for rewiring 4ft and 8ft fixtures to accept direct-wire LED tubes.

What is a Ballast?

A ballast is a legacy component used in fluorescent fixtures to regulate current and provide the initial voltage "strike" to illuminate the gas inside the tube. In modern LED applications, the ballast is unnecessary because LED tubes contain internal drivers. Bypassing the ballast eliminates the "humming" and flickering associated with aging fixtures and significantly lowers maintenance labor costs over time.

Step 1: Specification and Planning

Before beginning, identify whether your replacement LED tubes are Single-Ended or Double-Ended. This determines your wiring strategy. You will also need:

• Type B (Direct Wire) LED Tubes
• Non-contact voltage tester
• Wire cutters and strippers
• Commercial-grade wire nuts or lever connectors
• UL-Recognized Retrofit Warning Labels

Step 2: Power Isolation and Safety

Safety is the priority in any commercial electrical project. De-energize the circuit at the breaker panel. Use a non-contact voltage tester at the fixture to confirm that no power is present before removing the ballast cover or touching any wiring.

Step 3: Accessing the Interior Wiring

Remove the existing fluorescent lamps and the ballast cover (or "raceway" cover). This exposes the ballast and the wires leading to the lamp holders, commonly known as tombstones.

Step 4: Disconnecting the Ballast

Using wire cutters, trim the wires as close to the ballast as possible. Remove the ballast from the fixture. In older facilities, be aware that ballasts manufactured before 1979 may contain PCBs and must be disposed of as hazardous waste.

[Image: Diagram showing wires being cut from a ballast in an industrial fixture]

Step 5: Wiring the Sockets (Tombstones)

This is the most critical step and varies based on your tube type:

• Single-Ended Tubes: These require power to be delivered to only one end of the fixture. You must use non-shunted tombstones. Connect the Line (Hot) wire to one side of the tombstone and the Neutral wire to the other side. The socket at the opposite end of the fixture acts only as a physical support.
• Double-Ended Tubes: These are more common in commercial shops and garages because they can often utilize existing shunted tombstones. Connect the Line (Hot) wire to the socket(s) at one end and the Neutral wire to the socket(s) at the opposite end.

Step 6: Securing Connections and Labeling

Once rewired, secure all connections with wire nuts. Ensure that no bare copper is exposed. Crucially: Affix the "Retrofit Warning Label" included with your LED tubes to the inside of the fixture. This is an OSHA and electrical code requirement to warn future maintenance staff that the fixture no longer uses a ballast and cannot support fluorescent lamps.

Step 7: Final Assembly and Testing

Replace the ballast cover and install your new LED tubes. Restore power at the breaker. The lights should illuminate instantly without flickering. If you are retrofitting a large commercial space, verify the light levels with a lux meter to ensure the environment meets IES workplace standards.

Conclusion

Performing a ballast bypass is a high-ROI upgrade for any commercial shop, garage, or office. By removing the middleman—the ballast—you create a simplified, high-efficiency lighting system. For more information on maintaining your commercial facility, visit our Outdoor Lights FAQs or our Landscape Lights FAQs.