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T8 / T12 Bi-Pin Non-Shunted Sockets

What Is a Non-Shunted T8 Socket?

A non-shunted tombstone, also known as a non-shunted lamp holder, delivers power through a single electrical path. These sockets are essential for fluorescent fixtures using programmed start, rapid start, or dimming ballasts, and are required when installing ballast bypass (Type B) LED T8 tubes.

If your fixture has an instant start ballast, it likely uses shunted sockets—but these must be replaced with non-shunted T8 sockets for direct wire LED installation.

When Do You Need Non-Shunted T8 Sockets?

  • When retrofitting fluorescent fixtures for Type B LED tubes
  • If you're replacing old, damaged sockets in fixtures using programmed or rapid start ballasts
  • When upgrading to LED and bypassing the ballast for energy efficiency and lower maintenance
  • For T8 and T12 straight tube or U-bend configurations

Types of Non-Shunted Lamp Holders Available

Individual Non-Shunted Sockets

Perfect for single-lamp retrofits or replacements; compatible with many T8 and T12 bi-pin lamps.

Non-Shunted Socket Kits

Ideal for retrofitting 2, 3, or 4-lamp fixtures with direct wire LED tubes. These kits include:

  • Pre-wired sockets for easier installation
  • Color-coded connectors (e.g., red = powered, green = non-powered)
  • Quick-connect terminals to save time on job sites

Always confirm that your LED tubes require non-shunted sockets before installation.

Frequently Asked Questions

What is a non-shunted lamp holder?

A non-shunted lamp holder has separate electrical contacts and only one electrical path per pin. These are required for ballast bypass LED tubes where power is supplied to one end of the tube.

How can I tell if my socket is non-shunted?

Use a multimeter to test continuity across the terminals. If there is no continuity between the contacts, it is non-shunted. Shunted sockets show continuity across both terminals.

Can I use non-shunted T8 sockets with a fluorescent ballast?

Yes, but only in programmed start or rapid start ballasts. If your fixture has an instant start ballast, it likely uses shunted sockets instead.

Are non-shunted tombstones required for LED tube installation?

Yes, for Type B (ballast bypass) LED tubes, non-shunted tombstones are required to safely deliver line voltage directly to the tube.

Need help finding the right non-shunted T8 socket for your fixture? Contact our lighting experts at 1-877-381-4281 and we’ll match you with the right solution fast.