Light Fittings - Sockets & Connectors

There are countless light fittings and caps. To make matters worse, some fittings are known by multiple names. Here's a short list of fittings - which is not meant to be an extensive list of all available lamp caps, but it shows the most common ones that we use and sell.

Bi-Pin Connector

G4/G6.35 - Halogen Capsule
G4 and G6.35 bulbs are a small type bulb; the pins are just 4mm or 6.35mm apart. They are low voltage bulbs usually requiring 12V or 24V. We have a small adaptor socket [item discontinued] that can handle Halogen capsules (G4, G6.35) as well as MR16s (G5.3 - see below). Careful: never handle these bulbs with bare hands. Firstly, they might be very hot (hotter than incandescent light bulbs); secondly, the oil from human fingertips can damage the quartz envelope when it is heated.

MR16 - Multi-faceted Reflector
Halogen MR16 lamps consist of a halogen capsule integrated with a pressed glass reflector. The MR16 fitting has two sharp pins which are 5.3mm apart (which is why they are also known as G5.3 or GU5.3). MR16 fittings are primarily used for 12V LED or halogen lights and are one of the most common types of fittings used for low voltage downlighting. "MR" stands for multifaceted reflector, a pressed glass reflector with the inside (reflecting side) surface composed of facets and covered by a reflective coating. 16 is the diameter in eighths of an inch across the front face (16/8" = 2" = 51 mm).

The reflective coating of MR16 lamps can be either dichroic or aluminium. An aluminium coating is a thin film of aluminium that reflects both heat and light. A dichroic coating is a thin, non-metallic film that allows heat to pass through the reflector while it reflects light forward. Hence only specific lamp holders are suitable for dichroic lights.

Edison Screw Fittings

We have two types of Edison screw fittings - named after the inventor Thomas Edison. The bulb has a threaded metal base which screws into a matching socket. Caution: Edison type sockets have bare connectors that are exposed when the bulb is removed.

E27 - 27mm Edison Screw
The E27 is known as the original Edison Screw and is generally used in 230V light bulbs although we stock some 12V fluoro globes (5W and 7W) with E27 threaded base. The E27 is also a common type of fitting for standard household light fittings. Caution: the E27 has bare connectors that are exposed when the bulb is removed.

E17 - 17mm Edison Screw
Smaller version of the Edison screw. The E17 is not to be confused with the more widely spread E14 - which is commonly used in 230V table lamps. The E17 range was developed for extra low voltage applications (12V or 24V DC).

Bayonet Cap Fittings

The bayonet cap fitting is the standard fitting in Australia, New Zealand, the UK, Ireland, India and most other places the British once colonised. As with the Edison type sockets, the connectors are exposed when the bulb is removed.

B22 - BC Bayonet Cap
The standard size Bayonet fitting for 230 Volt wiring although we stock some 12V & 24V incandescent globes with BC base. Some claim it is slowly becoming extinct but it looks like it will be around for many years to come. We sell an adaptor that allows 2- pin halogen or LEDs to be fitted into a bayonet socket [item discontinued].

B15- BC Bayonet Cap
A small bayonet fitting approx 15mm pin to pin (also known as BA15). This fitting is often found in motor homes, camper-vans, etc.