GU24 bulb base reference
GU24 is a mains-voltage twist-lock base designed to enforce the use of efficient bulbs; it intentionally cannot accept incandescent replacements.
Exact specs
| Designation | GU24 (4-pin cluster, twist-lock) |
|---|---|
| Pin spacing | 24 mm |
| Voltage | Mains (120V US) |
| Energy code context | Required in some US jurisdictions under Title 24 (CA) and other energy codes |
| Typical wattage | 9W–26W LED/CFL equivalent |
What fixtures commonly use it
Recessed cans, flush-mount ceiling fixtures, and hard-wired lamps installed to California Title 24 energy standards often use GU24 sockets.
What it's interchangeable with
GU24 LED, CFL, and some specialty bulbs that carry the GU24 twist-lock form factor work directly. GU24-to-E26 adapters exist but defeat the energy code intention.
What it's NOT interchangeable with
GU24 does not accept standard E26 bulbs or any other screw/pin base. GU10 is a different system entirely.
Common mistakes
- Attempting to screw an E26 bulb into a GU24 socket.
- Not finding replacement bulbs locally — GU24 LED options may be online-only in some regions.