Types of lamp holders and sockets: how to choose the right one for your lamp

Choosing the right lamp holder or socket is essential to ensure the safety, performance, and aesthetics of a lamp. Although they may all look the same at first glance, there are significant differences in size, voltage, type of connection, and materials. In this guide, we explain the main types of lamp holders and sockets, their characteristics, and the situations in which each is used.

What is a lamp holder or socket?

The socket is the metallic or ceramic part of the bulb that allows its electrical connection with the lamp. The lamp holder, on the other hand, is the support where the socket is screwed or fitted. Both must match in format and size to ensure correct installation and avoid contact failures or overheating.

Main types of sockets and their characteristics

E14 lamp holder (small screw)

The E14 socket, also known as “small screw”, is one of the most common in small lamps, wall sconces, or bedside tables. It has an outer diameter of approximately 17 mm and is used for low or medium power bulbs. It is ideal for LED, filament, or classic incandescent bulbs that do not exceed 40 W.

Thanks to its compact size, the E14 lamp holder fits decorative luminaires, chandeliers, or narrow design lamps. Additionally, it is one of the most versatile models on the market and is made from materials such as porcelain, thermoplastic, or metal.

E27 lamp holder (standard Edison screw)

The E27 socket is the most widely used international standard in homes and offices. Its name comes from Thomas Edison, and the number indicates its outer diameter: 27 mm. It is used in ceiling, table, or floor lamps and supports all types of bulbs: LED, halogen, or incandescent.

It is the most versatile and easy-to-find format. Most LED bulbs on the current market are designed to fit an E27 lamp holder, as it offers a secure connection, great thermal capacity, and simple installation.

E40 sockets (industrial use)

The E40 sockets are designed for high-power or industrial use luminaires. Their outer diameter is around 39 mm and they allow high-performance bulbs, such as sodium vapour, metal halide, or industrial LED bulbs.

They are made from materials with high thermal resistance — usually porcelain or aluminium — and are used in industrial warehouses, public lighting, or outdoor projectors. They can support power levels of up to 400 W or more, ensuring safety and durability.

B22D and B15D sockets (bayonet type)

In countries like the United Kingdom or France, bayonet type sockets are common. The B22D and B15D models are equivalent to our E27 and E14 respectively. Instead of screwing in, these bulbs are fixed with a simple quarter-turn twist.

The B22D has an outer diameter of about 26 mm, while the B15D measures about 17 mm. Their locking system prevents false contacts, making them ideal for lamps in frequent use or in places with vibrations, such as trains, vehicles, or public spaces.

G4, G6.35, and GX5.3 sockets (bipin or two-pin)

These models, known as bipin or two-pin, are mainly used in low voltage halogen or LED bulbs. They operate at 12 V and require a transformer if connected to a domestic 230 V network.

The difference between them lies in the spacing between the pins: G4 (4 mm), G6.35 (6.35 mm), and GX5.3 (5.3 mm). They are very common in recessed spotlights, display cabinets, furniture, and compact design luminaires.

G9 lamp holders

The G9 is a very popular format in modern lighting fixtures. It allows for very compact bulbs and operates directly at 230 V, so no transformer is needed. The fitting is done by pressure, without threading, which allows for a quick and safe change.

It is ideal for small lamps, bathroom or wall sconces, where a discreet design with good light output is desired. They are available in both halogen and LED versions.

GU10 lamp holders (LED spotlights)

The GU10 lamp holder is currently the most used in LED spotlight bulbs, especially in recessed or track lighting. It operates directly at 220–230 V and its connection is made by pressure and a ¼ turn twist.

Its anchoring system prevents the bulb from loosening due to vibrations or heat, allowing for a simple and secure installation. It is the most widespread standard in modern domestic lighting.

G53 lamp holders (industrial AR111 connection)

More than a lamp holder, the G53 is a type of connection used in large-format bulbs, such as industrial AR111. The connection is made directly via terminal blocks, without a traditional lamp holder, and operates at 12–24 V.

It is used in shop windows, stores, museums, or industrial warehouses, where powerful and directional light is required. These bulbs are available in both halogen and LED versions.

Materials and finishes of lamp holders

Lamp holders can be made from different materials depending on the use and desired aesthetics:

• Porcelain: excellent heat resistance. Recommended for powerful or industrial lamps.
• Metal: elegant and durable, ideal for decorative or vintage style lighting fixtures.
• Plastic or thermoplastic: lightweight and economical, perfect for DIY projects or low-power domestic lamps.

When choosing a lamp holder, always check the maximum supported power, the working voltage, and the safety certification (CE).

Tips for choosing the right lamp holder

• Check the type of lamp holder indicated by the bulb (E14, E27, GU10, etc.).
• Ensure that the voltage and power are compatible with your installation.
• If you are changing the type of lamp holder, also replace the corresponding lamp holder.
• Opt for quality materials, especially in areas of heat or humidity.
• Always disconnect the power before handling a lamp.

Where to buy quality lamp holders and fittings

At LIGHTING DIY, you will find a wide range of lamp holders, fittings, and electrical accessories to assemble your own lamp or replace old components. If you can't find the model you're looking for, our team will advise you and source it for you without any problem.