External sign bulbs are often BC light Bulbs. Bayonet Cap (BC) light bulbs are used for sewing machines, street signs, and car lights. The bayonet connector (for electrical use) is a fastening mechanism that has two parts designed to lock together and stay locked until manipulated apart: a cylindrical male side with radial pins, and a female receptor of an L-shaped slot and springs to keep the parts locked together. The standard size bayonet light bulb socket is BC or B22d-2 or B22.
The History
The first use of this type of mount was in the 13th Century by the Al-Jazari Muslim warriors. They mounted candles and bayonets using these stable connectors.
Country of Origin
This mount was the standard fitting of Britain’s lighting fixtures and still is for many of her former colonies such as India, Australia, Ireland New Zealand, Africa, Hong Kong, and the Middle East. It is also still Britain’s standard fitting for light bulbs. Canada is the only former colony that doesn’t commonly use the bayonet mount for light bulbs. In France and Greece, the older standardizations are still being used. That means BC connectors are still common there.
Wattages Available
Bayonet BC light Bulbs are made in many different wattages and many varieties of lighting sources. Halogen, incandescent, and LEDs are the types of lighting that use bayonet fittings. The wattages range from the smallest of 2.8 volts-.94 amps to 12 volt-2.3 watts and the highest of 20 watts to 50 watts.
Appearances of the Bulb
The bayonet light base is frequently used in machines and elevators because the locking mechanism withstand the vibration of movement of the machine’s elements. The connector secures the bulb which can take on numerous shapes: pointed, tubular, flat top, spotlight/floodlamp, tapered, and globe.
Removing a Bayonet Bulb
When working with a bayonet cap, the removal of the light bulb requires a certain methodology. Hold the bulb housing firmly and push the bulb further into the housing and at the same time twist in an anti-clockwise manner or direction. Pull the bulb toward you to withdraw it from the housing.
Bayonet bulbs are unlike the traditional screw cap bulbs. They require additional thought and skill to install and remove. However, the same science is employed in how the light bulb works, no matter how much finessed is needed to install it in its housing. The main difference between a bayonet bulb and a traditional screw cap bulb is its connector providing a different level of security so that it doesn’t get jarred loose by vibrations from the machinery.
