How to identify G5
- Two pins appear at each tube end.
- Measure between pin centers.
- Read the tube length and ballast label.
Where it is commonly used
Common use is a clue, not proof. The fixture label and model documentation take priority over a visual match.
Bulb shapes sold with this base
You may see these shapes with a G5 base. The base code does not guarantee the bulb width, length, beam angle, or clearance.
Before you buy a replacement
- Match tube length and electrical configuration.
- LED tubes use different ballast or direct-wire arrangements.
- Do not confuse G5 with GU5.3 reflector bases.
Quick answers
Questions about the G5 bulb base
What is a G5 bulb base?
G5 is the miniature two-pin base used at each end of many T5 linear lamps. It does not identify ballast or LED wiring compatibility.
What size is a G5 bulb base?
G5 has a nominal 5 mm pin spacing. Pin spacing is measured from the center of one pin to the center of the other. Use the printed base code when available because a visual estimate is not conclusive.
Where is a G5 bulb base commonly used?
Common examples include t5 fluorescent tubes, t5 led tubes, cabinet fixtures, linear luminaires. Fixture type is only a clue; confirm the code on the bulb, socket, fixture label, or manufacturer documentation.
Can I choose a G5 replacement by appearance alone?
No. Match the G5 connection first, then verify voltage, actual input wattage, bulb dimensions, fixture restrictions, controls, and any enclosure or location rating required by the installation.