There are four commonly used thread size groups for mains supply lamps:
- Candelabra: E12 North America, E11 in Europe
- Intermediate: E17 North America, E14 (Small ES, SES) in Europe
- Medium or standard: E26 (MES) in North America, E27 (ES) in Europe
- Mogul: E39 North America, E40 (Goliath ES) in Europe.
The code number of a bulb consists of a letter or letters followed by a number. The letter indicates the shape of the bulb and the number relates to the diameter of the bulb in eighths of an inch. The mosts commonly used household bulb is the A-19. The bulb is “A” type and the diameter would be 23/8”. A 65BR40 is a 65 watt reflector 5” in diameter.
MapAWatt bulb sizes
A Bulb By Any Other Name…
C7 Bulbs have a candelabra or E12 base. This size bulb is typically used for chandelier-type fixtures and decorative lighting.
C9 Bulbs have an intermediate or E17 base. These are historically known as the old Christmas light bulb size.
Medium Bulbs have a E26 base (E27 in Europe). This is the same size as a standard household bulb.
ceiling fan by fireplace
A15 e12 candelabra bulb
e12 candelabra screw type a15
A Arbitrary (standard) – universal use for home lighting
- Candelabra: E12 North America
ceiling fan by fireplace bulb type: a15 base type: e12 - candelabra screw - 12mm diameter