Atlantic Illumination Entertainment Lighting

AIEL Instructional


This Article will Discuss the
Various Socket Types used
in Stage Lighting Fixtures



Preliminary     Socket Materials

Socket Types     Reference Table



    The most important component of a stage lighting fixture is its electrical socket. Without it, most lamps cannot be held correctly, and, screw terminals excluded, none would have the electrical connections needed to emit light.

    Various sockets have been developed over the years to provide the proper connection, orientation, and filament height, along with the mechanical abilities to hold the lamp and to dissipate some portion of the heat transmitted or radiated toward the socket. At least some of these different versions were only made because patents of a given socket type prevented usage by rival companies.

    Here is an initial article that will discuss socket aspects in regards to the fixtures that use non-LED lamps. This will be followed by a reference table that gives the typical types with their common names and their IEC (International Electrotechnical Commission) designations.



    Electrical sockets grew out of connectors for some lamps that had only screw terminals to attach the lamp to its voltage source. This method is still seen today in very rough service situations such as marine and railroad applications.

    Sockets came about as a way to quickly replace failed lamps, and as an alternate method to hold the lamp in place. These sockets were originally made from metal with a cardboard insulator. Some very cheap sockets that used low-wattage, low-heat sources were made of metal that was insulated with wax! (These could still be seen as late as the 1950s in some parts of the world.) Later, an early type of plastic, Bakelite, began to be used; it, or a similar material is still employed today in low-wattage, typically residential, fixtures.

    However, as light and heat output increased in lamps designed for performance and other demanding purposes, socket insulators began to be made of porcelain because many materials deteriorated too easily. These are often encased partly or completely in metal for strength and heat-dissipation purposes.



    As manufacturers developed different lamps for specific purposes, or because they made lamps to fit sockets requested by fixture builders, various types have come into the market over the decades. The requests came about due to designers that wanted smaller fixture bodies with more efficient optics. This was especially true in products such as projection and medical equipment, which demanded more compactness coupled with new techniques of providing light to where it was desired, and by innovative methods.



This table focuses on sockets used in entertainment industry
equipment, but will grow to include those from other professions.
Be aware that sockets will often appear more than once because the
table is cross-referenced.
Note that there are variations of many of these sockets, as used by
those other professions, and that they have different IEC designations.
This table will endeavour to include these as research continues.

To directly locate a Socket without scanning the table,
please use your browser's built-in "Search" function.
For information regarding this feature,
see Intra-Page Search)

Reference Table

Type IEC Designation
Bayonet: Single-Contact BA15S
Bayonet: Double-Contact BA15D
Bi-Pin: MR8, MR11 GU4, GY4, GZ4
Bi-Pin: Medium G9.5
Bi-Pin: Prefocus G29.5
Bi-Pin: Medium Prefocus GY9.5
Candelabra: Miniature (MiniCan) E11
Candelabra: Screw E12
Double-Ended R7s
Extended Mogul End Prong GX16d
Medium Bi-Pin G9.5
Medium Side Prong G16?
Medium Two-Pin GY9.5
Miniature Candelabra (MiniCan) E11
Mogul Bi-Post G22
Mogul End Prong GX16d
Mogul End Prong, Extended GX16d
Prefocus, Bi-Pin G29.5
Prefocus, Bi-Pin, Medium GY9.5
Prefocus, Candelabra ?
Prefocus, Medium PS20
Prefocus, Mogul P40s
Screw, Candelabra E12
Screw, Intermediate E17
Screw, Medium E28
Screw, Miniature E10
Screw, Mogul E39
Ferrule Contacts (No actual socket)
Screw Terminals (No actual socket)

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Stage Lighting Socket Guide: Text Format

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