Standard Household Light Bulb Base Size

Medium standard base code.

Standard household light bulb base size.

Almost all household bulbs have a medium screw base sometimes called an edison screw 1 16 inches in diameter with 7 threads per inch. Unlike the light bulb shapes the number in the light bulb base measures the light bulb base diameter in millimeters. 1 888 455 2800 fax 1 508 363 2900. Screw bases come in several sizes and they are referred to by both a descriptive name and size.

Pin type bases are normally used for track lighting landscape bulbs. Numbers in a bulb code indicate size in millimeters or eighths of an inch. Bulbs with a base that looks like a medium base but isn t are made to defeat bulb thieves in public places. The letter or letters in a bulb code indicate either shape or special features such as reflector type.

It has a pear like shape and is typically fitted to either an edison screw or a bayonet cap base. The candelabra e12 has a diameter of 12 millimeters. They are commonly used for general lighting in standard light fixtures such as ceiling lights lamps can lights outdoor spotlight and flood light fixtures and vanity lights. Common bulbs with e26 e27 bases.

The number that follows the a designation indicates the nominal major diameter of the bulb either in one eighth. Every light bulb has identifying characteristics that are represented by a letter or series of letters and a number. Our household light bulb types include a range of options for a variety of applications including energy efficient led versions that save time money and energy due to their long life. These are known as light bulb codes.

Look at your fixture to determine its base type. Look at your fixture to determine its base type. Most common light bulb uses including lamps recessed flush mount flood lights are going to have one of the first three base types shown above. The light bulb commonly used since the early 20th century for general purpose lighting applications with a pear like shape and an edison screw base is referred to as an a series light bulb this most common general purpose bulb type would be classed as a19 e26 or the metric version a60 e27.

Bulbs with these base types are available in many different styles. The a series light bulb is the classic glass light bulb shape that has been the most commonly used type for general lighting service gls applications since the early 20th century. Most light bulbs screw into a socket.