GU24 connector

Compact fluorescent light bulb with GU24 connector

A GU24 connector is fitting for compact fluorescent light bulbs (CFL) or LED bulbs that uses a bayonet mount-like twist-lock bi-pin connector instead of the Edison screw fitting used on many incandescent light bulbs.

Advantages

• Use of the GU24 fitting provides compliance with a 2008 ruling by the California Energy Commission under Title 24 (California Building Standards Code) to require high-efficiency lighting on all residential remodels and new construction. The GU24 fitting maintains the energy efficiency of the light by preventing an occupant from using an incandescent bulb instead of a CFL. Adapters to use incandescent bulbs in a GU24 fitting are illegal in the State of California as they would be a fire hazard in fixtures designed for the lower heat output of a CFL bulb.^[1]
• The GU24 fitting allows the overall length of the bulb to be shorter since the threaded base is eliminated.
• Neither of the electrical contacts are exposed during bulb installation or when in service, offering improved protection against electric shock.

Disadvantages

• Requires proper alignment to install, but most bulbs/sockets obscure the pin orientation.
• No 3-way lamp support.
• Incompatibility with other bulb types.
• Will maintain a price premium while they are mandated in a minority of jurisdictions. As of Q3 2014, equivalent GU24 bulbs are 3 times more expensive than Edison bulbs.

References

1. GU24: New Pin-Base for CFLs, LEDs, Environmental Building News, October 1, 2011