What Is The Standard Light Bulb Base?

What are the Standard Light Bulb Base Socket Types and Sizes?

When considering different types of light bulb socket bases, it can get quite confusing. Many people get confused about the different numbers used for each light bulb base and their meanings.

The standard light bulb base is E-26.  The E-26 light bulb base must use an E-26 socket; you will find an E-26 socket on many tables and floor lamps sold in the United States.  The E-26 socket is also known as the standard socket. Besides the E-26 lamp holder socket, the other significant U.S. socket types are E-12, E-19 and E-39.

Table of Contents

E-26 Lamp Holder, Sockets and Light Bulb Explained.
E-26 Lamp Holder, Sockets and Light Bulb Explained.

E-26 – Standard Light Bulb Base and Socket

The standard UL size of all lamp holder sockets and light bulbs is the E-26 lamp holder socket and light bulb; most people refer to this as a standard light socket and a light bulb or E-26. Most table and floor lamps you purchase will use an E-26 Socket and an E- 26 light bulb. This light bulb is also known as a Medium Edison Screw (MES) light bulb.

An E-26 light bulb or lamp socket uses an E-26 size light bulb base that is 26 mm in diameter and will fit into an E-26 size lamp holder socket. One way to easily know if your light bulb or socket uses an E 26 bulb is to measure the bottom of the light bulb or the inner part of the socket.

The photo below shows you how to measure your socket to see if it will fit an E-26 light bulb base.

How To Measure An E Socket Size
How To Measure An E-Socket Size

A few things to remember about the standard E-26 sockets and light bulbs:

  • E-26 does not refer to the light bulb’s shape or glass part.
  • E-26 only refers to the light bulb base size that will screw into the socket.
  • Manufacturers will usually print E 26 on the light bulbs.
  • An E-26 bulb can also be an incandescent or LED light bulb.
  • E-26 also refers to the size of the lamp holder. So if someone says this lamp base has a UL-certified E- 26 lamp holder socket, they mean that it also uses an E-26 light bulb.

Types of E 26 Sockets for Table and Floor Lamps

When we manufacture UL-certified table or floor lamps, we usually use an E 26 lamp holder; we use either heavy-duty or regular lamp holders. The heavy-duty or regular lamp holder refers to the outer casing of the lamp holder socket itself. Most of the inner parts used to manufacture heavy-duty or regular sockets on a lamp base are the same.

Heavy-duty Vs Regular Lamp Holder Sockets
Heavy-duty Vs. Regular Lamp Holder Sockets

Here is a chart we have done to compare to you the difference between the E-26 heavy-duty and regular lamp holder sockets.

Description Heavy Duty Lamp Holder Socket (E-26)Regular Lamp Holder Socket (E-26)
Light Bulb Size E-26E-26
Socket Light Bulb Opening Size26 mm or 1 inch26 mm or 1 inch
Socket KindsKey or KeylessKey or Keyless
Standard Socket Types 2-way, 3-way, and Dimmer 2-way, 3-way, and Dimmer
Lamp Holder MaterialMetal Metal, Ceramic, and Plastic.
Standard Finishes Polished Brass and Polished Nickel Brass and Nickel, White (Ceramic) and Black (Plastic).
Other Finishes Antique Brass, Polished Copper, Satin Nickel, Satin Black Antique Brass, Polished Copper, Satin Nickel, Satin Black
Assembly Lamp Holder Socket Screws Together Lamp Holder Socket Clips Together
Turn Knob (Key)Usually, always metal Usually Black Plastic (sometimes the black knob is switched to a metal knob).
Standard Use Table, Floor Lamps, and Pendants Table, Floor Lamps, and Pendants
UL Parts Standards Parts (most companies request a heavy-duty harp holder with a heavy-duty socket). Standard Parts
Cost More expensive than the regular socket, usually found on higher-end lamps and lighting, Cheaper than the heavy-duty socket.
Comparison UL Heavy Duty and Regular Lamp Holder Sockets

As you can see from the above table, the heavy-duty and regular sockets’ main difference is the quality of the lamp holder’s outer casing, the on/off turn knob, and how the socket itself assembles.

There is no hard-fast rule about which kind of company will use the heavy-duty socket and which uses the regular socket for their lamp production. The heavy-duty socket is a more expensive and higher-end socket than the regular socket; we have found that most higher-end lamp brands will use the heavy-duty socket for their lamp production, not the regular socket.

If you would like to understand more about these two different kinds of E-26 lamp holder sockets, you can watch our video below, which clearly shows the difference between the E-26 heavy-duty and E-26 regular UL lamp holder sockets.

Please click on the video below:

Comparison Between the Regular and Heavy Duty UL Lamp Holder Sockets

The E-26 lamp holder socket and light bulb in the standard light bulb used in most lighting. The other significant sockets and light bulb bases are E-12, E-19, and E-39.

What Do The Different E-Sockets Mean?

Below we have drawn out the significant UL-certified E light bulb bases and their sizes. The E-12 uses the smallest light bulb base, while the E-39 uses the largest. The standard light bulb base of the E-26 size is in the middle of these sizes.

E light bulb base comparisons
E light bulb base comparisons (United States Standard Light Bulb Bases)

Each of these four basic E lamp holder sockets will fit a different type of light bulb base. The 4 types are E-12, E-19, E-26 (standard light bulb base), and E-39, the major UL-certified light bulbs and lamp holder sockets sold in the United States. The European E-26 is called E-27 and must use an E-27 bulb.

The “E” on each light bulb or socket stands for Edison, after the American inventor Thomas Edison. Thomas Edison is considered one of the greatest inventors of all time as he developed key inventions in electrical power, mass communications, sound recordings, and motion pictures. Thomas Edison’s major inventions included the phonograph, the motion picture camera, and the light bulb.

The “E” for the light bulb bases is also known as the ES for the Edison Screw system; the ES system is used today with many light bulb attachment systems. The Edison Screw (ES) refers to how the light bulbs will be screwed into the lamp holder socket. The light bulbs have a right-hand threaded metal base (caps) that will screw into a matching threaded lamp base socket.

How to measure an E Light Bulb Size
How to measure an E Light Bulb Size

The number after the E on the sockets or light bulbs refers to the diameter in millimeters (mm) of the base of the light bulbs that screws into the lamp holder socket.

The below table we have organized shows each of these E sockets types, their standard industry names, corresponding light bulb types, and the actual light bulb base dimensions that are sold in the United States:

Socket Holder Size Lamp Holder Socket NameLight Bulb TypeLight Bulb Base Dimension
E-12 Candelabra SocketE-1212 mm (0.47 inch)
E-19 Intermediate SocketE-1919 mm (0.74 inch)
E-26 Medium or Standard socket E-2626 mm (1 inch)
E-39 Mogul socketE-3939 mm (1.53 inch)
Comparison between the UL-Certified E-12, E-19, E-26 and E-39 Lamp sockets

The two major lamp holder sockets that we use for manufacturing UL-certified lamps and lighting for home decor and home furnishing is the E-12 (candelabra) and E-26 (medium or standard socket).

Mondoro has its own UL-certified lamp factory outside Hanoi, Vietnam. In the factory, we assemble UL lamps (table, floor, and other portables) and make some of our shades. If you are interested in finding out more about how we can help you manufacture some UL-certified lamps, please contact Anita by clicking here or write her directly at her email by clicking here. We would love to hear from you and hear how we can help you.

Find out more about how Mondoro can help you create, develop, and manufacture excellent home decor and furniture products – don’t hesitate to contact me, AnitaCheck out my email by clicking here or become a part of our community and join our newsletter by clicking here.

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