Tube lights and its sizes; Tube light diameters

Tube lights are part of every industry and household. LED tube-lights are also coming in same sizes that of traditional lights.

Diameter of tube-light is described in 1/8 of the inch. So a T8 tube light is 1 inch diameter tube-light. This is obtained by simply multiplying 1/8 by numeric letter of description of tube light.  

Sizes of tube lights vary from T2 to T17.

Electronic ballasts, and T5 or T16 (⁵/₈" Ø or 15.875 mm Ø) for very small lamps which may even operate from a battery powered device.

Fluorescent tube diameter designation comparison
Tube diameter designations		Tube diameter measurements			Extra
Imperial-based	Metric-based	Inches Ø  (")		Millimeters Ø  (mm)	Socket	Notes
T4	N/A	4/8" Ø		12 mm Ø	G5 Bipin	Slim lamps, tube lengths may vary
T5	T16	5/8" Ø		15.875 mm Ø	G5	Supersedes T8, introduced in the 1990s
T8	T26	8/8" Ø	1" Ø	25.4 mm Ø	G13 bipin	From the 1930s. More common since the 1980s
T9	T29	9/8" Ø	11/8" Ø	28.575 mm Ø		Circular fluorescent tubes only
T12	T38	12/8" Ø	11/2" Ø	38.1 mm Ø	G13 bipin	Also from the 1930s. Not as efficient as new lamps
PG17	N/A	17/8" Ø	21/8" Ø	53.975 mm Ø		General Electric's

T8 tube-lights were most widely used in households were now days replaced with T5 tube-lights.

T5 Tube-Light length available is from 9 inch-21 inch and having power ranging from 2-15 watts.

T8 Tube lights length available are from 18 inch to 6 feet and power range is from 15 watt to 70 watts.

T12 Tube-lights length available are available from 18 inch to 8 feet and power range is from 15 W to 125 Watts.

1/8 of inch= 3.175 mm.

Applications of Tube-lights:-

(i)                T4 tube-lights are very compact and are having very easy installation, These are having very useful application in kitchen counters and worktops. Power consumption of these tube-lights is very low. Life of tube-lights is 9000 hours.

(ii)             T5 tube-lights are installed for efficiently lighting up Schools, factories, offices etc. Life of these tube lights is 20,000 hours. These lights have very low mercury content thus these have very minimum impact on environment. These lights uses specially designed blast which limits current into tube light. So prevents them from overloading. These blasts also enable them working above 20 kHz which gives instant start features to these tube lights.

(iii)           T8 tube-lights are most widely used tube lights and these are useful where there is need to see lot of details. These are useful in Stores, garages, offices, schools etc. These lights are having life more than 15,000 hours.

(iv)           T12 tube-lights are now vanishing out due to popularity of T8 lights. These are useful for lighting large areas such as offices and retail space.