How to identify B15d
- Look for two opposed side pins.
- Check for two contacts on the bottom.
- Measure the shell diameter with power disconnected.
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 B15d base. The base code does not guarantee the bulb width, length, beam angle, or clearance.
Before you buy a replacement
- B15s and B15d differ in electrical contacts.
- Automotive and household lamps can share a cap shape but not voltage.
- Match the appliance model when available.
Quick answers
Questions about the B15d bulb base
What is a B15d bulb base?
B15d is a small 15 mm bayonet cap with two side pins and two bottom contacts. It is smaller than B22d.
What size is a B15d bulb base?
B15d has a nominal 15 mm shell diameter. 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 B15d bulb base commonly used?
Common examples include sewing machines, decorative lamps, marine fixtures, specialty appliances. Fixture type is only a clue; confirm the code on the bulb, socket, fixture label, or manufacturer documentation.
Can I choose a B15d replacement by appearance alone?
No. Match the B15d connection first, then verify voltage, actual input wattage, bulb dimensions, fixture restrictions, controls, and any enclosure or location rating required by the installation.