LED tube lights (T5 / T8 LED tube lamps)

01

Choose Type A, B, C or hybrid

A presentation hosted by the US Department of Energy (TLED workshop, Denver 2016) classifies tubular LED lamps as plug-and-play, ballast-compatible UL Type A; integrated-driver, ballast-bypass UL Type B; external-driver UL Type C; and hybrids that are Type A and Type B. It notes that Type A lamps are not all equally ballast-compatible, since ballasts may be instant-start, programmed-start, dimming or emergency types, change from batch to batch and are discontinued; that Type A dimming has limited compatibility and range; that Type B lamps bypass the ballast, with single-ended designs needing at least one non-shunted lampholder per lamp and double-ended designs able to use the shunted lampholders of instant-start fixtures; and that converting a hybrid from Type A to Type B requires warning labels to be installed in the modified fixture. [2]

Editorial note: give the supplier the existing ballast make and model for Type A lamps and ask for the lamp's ballast compatibility list; for Type B, confirm whether the lamp is single- or double-ended and which lampholders it needs, and plan the fixture relabelling.

Give the supplier the existing fixtures and ballasts (make, model, type), lamp length and form factor (T8, T5), preferred type (A, B, C, hybrid), socket type (shunted or non-shunted), required lumen output and CCT/CRI, dimming or emergency needs, voltage, operating temperature, certifications, and warranty.

02

Check light output, distribution and wiring

DOE's CALiPER Application Summary Report 21 (March 2014) tested 31 linear LED lamps sold as alternatives to T8 fluorescent lamps to IES LM-79-08. Mean efficacy was similar to that of fluorescent lamps, but more than half of the products gave under 2,000 lm against about 3,000 lm for a 32 W fluorescent T8 lamp, and every lamp's luminous intensity distribution was directional or semi-directional rather than omnidirectional, which changes performance in the fixture. Lamps with diffuse optics averaged 90 lm/W (66–105 lm/W) and those with clear optics 101 lm/W (79–143 lm/W), diffusion reducing efficacy by about 10% on average. [1]

The report explains that instant-start ballasts use shunted lampholders and rapid-start and magnetic ballasts use unshunted ones, that linear LED lamps may be wired at one or both ends and need shunted, unshunted or no existing sockets, and that improper wiring can cause failure or dangerous conditions such as sparking, smoking or tripped breakers; it identified seven wiring configurations among the tested lamps. [1]

Editorial calculation: 101 / 90 ≈ 1.12, so in that 2014 sample the clear-optic lamps averaged about 12% higher efficacy than diffuse ones; products have changed since, so ask the supplier for LM-79 test reports of the exact lamp, in your fixture where possible. [1]

A current maker sheet gives the figures to ask for. TCP's LED Pro Line T8 spec sheet lists a 12 W, 4 ft Type A glass tube for instant-start ballasts drawing 14.9 system watts and giving 1,800 lumens (120.8 lm/W) at normal ballast factor, and a 13.5 W Type B ballast-bypass tube giving 1,800 lumens at line voltage (140.7 lm/W). Both are rated CRI 80, 50,000 hours, power factor 0.99, 120–277 V, G13 base, −20 °C minimum starting and 45 °C maximum operating temperature, 190° beam angle, and a 47.8 in length for the 4 ft tube; THD is under 8% at 120 V, ballast dependent. The sheet adds a list of instant-start ballast models tested with its Type A tube and notes that field conditions may differ from lab compatibility tests. [3]

Editorial calculation: on that sheet, removing the ballast (Type B) cuts system power from 14.9 W to 13.5 W for the same 1,800 lumens, about 9% less (1 − 13.5 ÷ 14.9), against the 32 W fluorescent lamp both are rated to replace. [3]

For rebate eligibility, the DesignLights Consortium's SSL Technical Requirements Tables V5.1 (effective 1 July 2020) set bare-lamp minimums for linear replacement lamps of 1,600 lm for 4 ft T8 and T5 lamps, 800 lm for 2 ft T8, 1,200 lm for 3 ft T8, 3,200 lm for 4 ft T5HO and 8 ft T8, and 1,400 lm for U-bend lamps, each at a minimum efficacy of 120 lm/W. The category covers both direct replacements and tubes that need ballast bypass, is limited to the DLC Standard classification, and from V5.1 is verified on bare-lamp performance only. [4] Editorial calculation: the 12 W, 1,800 lm TCP tube above is 150 lm/W at the lamp, but 1,800 lm over the 14.9 W Type A system watts is about 121 lm/W and over 13.5 W Type B about 133 lm/W; ask suppliers whether quoted efficacy is lamp-only or includes the ballast, and for the DLC listing if a rebate depends on it. [4] [3]

03

Trace the lamp parts

This is a functional reference built from the sources cited; it is not one maker's design.

04

Fill the specification fields with values for your fixtures

An LED tube quotation needs values for your fixtures. The table explains each field, gives published values where a reviewed source states them, and says what to obtain from the supplier.

05

Send the fixture, ballast and light data together

Paste it into your enquiry below or into an email to a maker, then replace every bracket.

Fixtures: [type; count; lamp per fixture]
Ballasts: [make; model; type]
Lamp: [T8 or T5; length]
Type: [A; B; C; hybrid]
Sockets: [shunted; non-shunted]
Light: [lumens; CCT; CRI; distribution]
Controls: [dimming; emergency]
Documents: [LM-79; compatibility list; certification]

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