LED Tube Bases: R17d (High Output), G13, and Single Pin

As a Denver-based LED lighting supplier, we at Denver LED Direct know that choosing the right LED tube often comes down to one crucial, small detail: the base, or end cap. Fluorescent fixtures were designed with several types of sockets, and converting to energy-efficient LED tubes requires knowing which base matches your existing setup.

Here is a breakdown of the three most common LED tube bases, their specifications, and the environments where you’ll typically find them.

1. R17d / High Output Base

The R17d base is instantly recognizable by its large, rotating white plastic cap with a recessed contact.

  • What it is: The R17d base is a high-power, recessed double-contact socket. The rotating end cap ensures the tube aligns properly with the fixture's internal wiring.

  • Common Use: You will primarily find R17d bases on 8-foot fluorescent and LED tubes.

  • Key Application: It is synonymous with High Output (HO) lighting. This base was initially designed for high-lumen, 8-foot fluorescent tubes and is still necessary for LED replacements in fixtures where maximum light output is required. These are frequently used in large commercial spaces, warehouses, outdoor signage, industrial facilities, and anywhere high ceilings or large areas demand powerful, bright illumination. Denver LED Direct regularly sources these for large-scale replacements. R17D base LED tubes are most commonly Type B -Ballast Bypass only. 

2. G13 Bi-Pin Base

The G13 base is the industry standard bi-pin connection and is the most widely used base for linear fluorescent and LED tubes.

  • What it is: The "G" stands for glass, and "13" indicates the pin-to-pin distance in millimeters. It features two metal pins protruding from each end of the tube.

  • Common Use: G13 bases are used on the vast majority of 2-foot and 4-foot LED T8 and T12 tubes.

  • Key Application: Its versatility makes it ideal for almost any commercial setting. It is the go-to choice for general office lighting, retail spaces, schools, and medical facilities. Due to its widespread use, G13 LED tubes are available in all three LED tube types (Type A - Ballast Compatible, Type B - Ballast Bypass, and Type A+B - Hybrid).

3. Single Pin Base (FA8)

The Single Pin, or FA8 base, is another end-cap primarily found on longer tubes.

  • What it is: The FA8 base features a single, round pin at each end of the tube. The pin sits flush with the end cap.

  • Common Use: Like the R17d, the single pin base is also mainly found on 8-foot fluorescent and LED tubes.

  • Key Application: Single pin fixtures are typically an older style of commercial lighting. The simple single-pin connection often indicates a fluorescent fixture that uses "shunted" sockets. Single pin LED tubes (or their compatible FA8 versions) are critical for retrofitting these older 8-foot fixtures in commercial or industrial buildings without the need for extensive rewiring. Like the R17D base most Single Pin tubes are Type B - Ballast Bypass only but more Type A & B  options are becoming available.  

Choosing the correct LED tube base is the first step toward a successful lighting upgrade. If you have any questions about identifying your existing base type—whether it’s R17d, G13, Single Pin, or something else—contact the experts at Denver LED Direct. We’re here to help you find the perfect LED solution for your Denver business.

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