Light Bulb Socket Sizes: Understanding The Standard Screw Fittings

The Edison screw (ES) is the most common type of lightbulb base, used in most incandescent bulbs and many halogen, compact fluorescent, HID, and LED bulbs. The size of the base is indicated by a code such as E26, where E stands for Edison and the number indicates the diameter of the base in millimetres. The E26 base, for example, is 26mm wide and is the most common type of base in the US. Other common Edison screw base sizes include E12 (candelabra), E17 (intermediate), and E39 (mogul).

Edison Screw (ES)

The name "Edison Screw" comes from its inventor, Thomas Edison, and the "E" in the designations "Exx" (e.g., E26) refers to "Edison". The "xx" in the designation indicates the diameter of the socket in millimetres. For example, an E26 bulb has a diameter of 26 mm.

The Edison Screw has become the international standard for light bulb sockets, used in over 80% of light bulbs worldwide. The screw comes in various sizes, from E5 to E40, with the number after the "E" representing the diameter size in millimetres.

The E26 and E27 are often interchangeable and are called the (Medium) Edison Screw, or MES or simply ES. It is the standard for most light bulbs, with E26 being the standard for 120-volt bulbs in America, and E27 being the standard for 230-volt countries in Europe. Their 1mm difference makes the bulbs interchangeable, and an E27 bulb can fit into an E26 fitting and vice versa.

The E12 is a small candelabra base, often used for night light bulbs and decorative light bulbs for chandeliers and bathroom mirrors. It is found in America, especially in old or imported fittings, but it is not common.

The E14 is also called the Small Edison Screw (SES) and is the standard for 230-volt bulbs, especially smaller candelabra bulbs. It is commonly used in Asia, Australia, Europe, New Zealand, Africa, and most South American countries.

The E17, or Intermediate Edison Screw (IES), is the standard for many 120-volt appliance lightings, such as microwaves, ovens, sewing machines, and refrigerators. It is also used as room lighting in tight or hard-to-reach spaces.

The E39 and E40 are commonly called the Goliath Edison Screw (GES). The E39 is often referred to as the Mogul Edison Screw or simply Mogul in the US. These sizes are fairly uncommon, but they are widely used in industrial and farm applications, such as warehouses, barns, and factories, with wattages above 250W.

E26/E27 base

The E26/E27 base is the most common light bulb base size in the United States. It is also known as the "medium" or "standard" Edison screw base, with a diameter of 26mm. This base is used for most incandescent, vintage LED, CFL, and halogen smart light bulbs.

The E26/E27 base is designed for use with lamps and lampholders that operate on 120V AC voltage. This is the standard voltage in North America, including the United States, Canada, and Mexico, as well as in some Asian countries such as Japan, Taiwan, and South Korea.

While E26 and E27 bulbs are mechanically interchangeable, there are important electrical safety differences between them. E26 bulbs are designed for use with 120V AC voltage and have a shorter screw length, a smaller insulator cap height, and a narrower screw diameter at the thread trough. On the other hand, E27 bulbs are designed for use with 240V AC voltage and have stricter requirements for the separation distance between live and neutral contacts. This is because higher voltages require a wider separation to reduce the risk of short circuits and electrical fires.

Therefore, it is important to use the correct bulb for the corresponding voltage and lampholder. While E27 bulbs can be safely used in E26 lampholders, using E26 bulbs in E27 lampholders can pose an electrical safety hazard at 240V AC.

E12 base

The E12 base is ideal for smaller lighting fixtures, like chandeliers, where a larger socket may not fit. The compact size of the E12 also allows for a more elegant and streamlined design, making it a popular choice for decorative lighting.

You can find E12 base bulbs at most hardware stores and lighting supply stores, as well as online. When purchasing, be sure to check the wattage and voltage ratings to ensure compatibility with your fixtures and bulbs.

Some common bulbs with E12 bases include:

• Small tube-shaped bulbs: T8, T6, T22
• Candle-flame-shaped bulbs: C7, C9, CA10, B10
• Small globe-shaped bulbs: G14, G16, G50
• Blunt-tipped bulbs: B10, B11, BA11

E14 base

The E14 base is a type of screw-in light socket commonly used for small light fixtures and appliances. It is also known as the Small Edison Screw (SES) and has a diameter of 14mm. This type of bulb is popular in Europe, Asia, Australia, New Zealand, Africa, and most of South America, where it is the standard for many small household bulbs.

The E14 base is used for a variety of applications, including chandeliers, wall sconces, table and desk lamps, kitchen appliances such as refrigerators and ovens, and even inflatable Santa Claus decorations. The bulbs themselves come in various shapes, including candle-shaped, golf ball-shaped, small reflector spotlights, and small decorative filament bulbs.

When choosing an E14 bulb, it is important to consider not only the shape and size but also the type of bulb. E14 bulbs are available as incandescent, halogen, and LED. LED bulbs, for example, do not contain toxic chemicals and have a longer lifespan than incandescent bulbs.

In summary, the E14 base is a versatile and widely-used light socket that can be found in homes around the world, offering a range of lighting options for various fixtures and appliances.

E17 base

The E17 base is a screw-type light bulb base with a diameter of 17mm. It is commonly used in ceiling fans and light fixtures, as well as Christmas lights and other decorative lighting applications.

E17 intermediate bulbs are available in a variety of colours, including warm white, soft white, daylight, and RGBWW (red/green/blue/warm white). They can also be dimmable or non-dimmable, with some options compatible with LED dimmers.

The E17 base is ideal for standard screw E-17 light bulb bases and can be found in a range of bulb shapes, including T8, T7, T7N, S11, and A15. These bulbs typically range from 15W to 40W and operate at voltages of 120V or 130V.

Some specific examples of E17 base bulbs include the Simba Lighting LED T8 40W Equivalent Bulb, the Sterl Lighting T6.5 Tubular Refrigerator Light Bulb, and the Kydely Dimmable E17 LED Bulb for microwave ovens. These bulbs can be purchased from retailers such as Walmart and Home Depot.

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