Caroline Van Wouwe

Caroline Van Wouwe

Finding your way around lamp fittings

E27, E14, GU10, GU5.3,… all types of lamp fittings. When you’re out to buy a new bulb and you’re not really sure which fitting it is you need, you might as well head straight back home. That’s why we’re going to try to explain some of the differences between fittings and help you find you’re way around the available choices.

Note: we only discuss the more common light sockets. There’s a whole lot of other, less familiar, versions, which are also available at our webshop. Here, you can make use of the filter ‘lamp socket’ to find all compatible lamps.

E27 Socket

E27 lamp

E27 lamp

The E-fitting derives its name from its inventor, Thomas Edison. He developed this screw thread fitting in 1909. That’s why this screw thread is also known as the Edison screw.

In most houses you’ll still find light fixtures with a standard E27 fitting. Their thread has a diameter of 27 millimeter and they require 230 Volt alternating current.

Discover all E27 LED lamps


E14 Socket

E14 lampen

E14 lamps

Nowadays we often see smaller versions of the Edison fitting. One of the more common, is the E14, which is frequently used in light fixtures, because of its more elegant looks.

Discover all E14 LED lamps


GU10 Socket

GU10 spot

GU10 spot

GU10 fittings have a bayonet mount with two pins at the bottom of the lamp. These pins are locked in clockwise into specials slots. Because this was the way bayonets were mounted on guns back in the day, they chose to name this type of socket after it. This is a fitting often used for halogen or LED lamps.

The numbers in the name, stand for the distance between the pins. So, with a GU10, there’s a distance of 10mm between them.

Please keep in mind that there’s a difference between GU10 en GZ10! A GZ10 lamp only fits in a GZ10 fitting, while a GU10, with its rounder base, fits in both. The “U” is an abbreviation for “Universal”.

Discover all GU10 LED lamps

Verschil GU10 GZ10

B15 Socket

B15 lamp

B15 lamp

In Australia, Ireland, New Zealand en the United Kingdom mainly B-connectors are used. These are bayonet sockets with pins on the side.

This kind of sockets always start with a ‘B’. The number indicates the diameter of the fitting. For instance, a B15 fitting has a diameter of 15mm. In Belgium the Ba15d, which works on 12V, is a often used version.


GU5.3 Socket

GU5.3 spot

GU5.3 spot

This kind of fittings has two metal pins which conduct electricity. That’s why they are also called bi-pin connectors. The distance between the pins is indicated by the digits after the GU. In this case, there’s 5.3 mm distance between the two pins.

Just the same as with the GU10, there’s also a GZ5.3 version of the GU5.3. The difference is just the same, a rounded (GU) or a rectangular base (GZ). So, a GZ5.3 won’t fit in a GU5.3 fitting, but it will work vice versa.

Discover all GU5.3 LED lamps


GU4 Socket

GU4 spot

GU4 spot

The GU4 socket is a smaller version of the GU5.3. Both have a similar bi-pin connector and require 12V low voltage. The diameter of the GU4’s head however is only 35mm, where the GU5.3’s measures 50mm. Logically, the distance between the GU4’s pins is 4mm.



G4 Capsule

G4 steekhalogeen

G4 halogen

Diodes with a G4 fitting have the same connector as the other G4 lamps. Also the distance between the pins remains the same – 4 millimeter.

Discover all G4 LED lamps



G53 Socket

G53 lampvoet

G53 light socket

A lot of large halogen spots use a G53 fitting. More recently an LED version of the G53 spots became available. As you might have guessed already, the 53 stands for 53mm between the pins.

Discover all G53 LED lamps


G9 Socket

G9 steekhalogeen

G9 steekhalogeen

A G9 socket is mainly used for 230V halogen lights and LED lamps. Of course, there’s a distance of 9mm between the pins.  But, different from the G4 capsule, the G9’s pins form a loop.

Discover all G9 LED lamps



G5 / G13 / 2GX13 Socket

G5 G8 2GX13

G5 G8 2GX13

These sockets are used for fluorescent tubes. A G5 fitting for example, is made for T5 tubes, which have 5mm distance between their pins. G13 sockets have a distance of 25mm and are used to connect T8 fluorescent tubes. 2GX13 fittings are used for circular fluorescent tubes with four contact point (two on the inside and two on the outside).

Discover all G13 LED lamps


R7s Socket

R7s halogeen

R7s halogeen

The R7S socket was developed for linear lamps (halogen or LED). The contact points can be found on both ends of the lamp.

Discover all R7s LED lamps

Sockets isn’t world’s easiest or most interesting subject, that’s why we only discussed the most common types. There are numerous other varieties. Below you can find an overview of the most frequent fittings.

Meest gebruikte fittingen

Some of the most used sockets