How it connects
Push-in friction fit where two straight parallel pins on the lamp insert into spring-loaded electrical contact sockets inside a heat-resistant ceramic or plastic body.
Male and female halves
Female socket with dual pin receptacles mating with a male lamp base having two parallel rigid pins.
Usually connects to
- G4 male bi-pin lamp base
- MR11 bi-pin halogen/LED lamp with G4 base
Common sizes
- 4.0 mm pin pitch (center-to-center spacing); pin diameter 0.65 to 0.75 mm; typically rated for 12V/24V low voltage up to 4A or 20-50W.
Where it is used
landscape lightingunder-cabinet lightingpuck lightschandeliersautomotive and RV interior lightingmarine lighting
Variations
- Ceramic round socket with flying wire leads
- Flanged socket with screw mounting ear holes
- Combo multi-base sockets accommodating G4, GU5.3, and G6.35
How to recognise it
Identified by a small round or oval heat-resistant ceramic body with two round or rectangular pin entry holes spaced exactly 4.0 mm apart, with lead wires exiting the back.
Often confused with
| Confused with | How to tell them apart |
|---|---|
| GU4 socket | GU4 shares the 4.0 mm pin pitch but features side retention grooves on the lamp base and corresponding socket latches/bumps, whereas G4 is smooth without grooves. |
| G6.35 / GY6.35 socket | G6.35 has a wider 6.35 mm pin pitch and thicker pins (1.0 mm or 1.25 mm), compared to G4's 4.0 mm pitch and ~0.7 mm pins. |
| G9 socket | G9 is a mains-voltage (120V/230V) looped-pin or bent-sheet base with 9.0 mm pitch, whereas G4 uses two straight solid wire pins spaced 4.0 mm apart. |
Also called
G4 lamp holderG4 bi-pin base socketminiature bi-pin socket G4
Good to know
Some universal sockets are manufactured with elongated dual-leaf spring contacts to accept both G4 (4 mm pitch) and larger bi-pin bases (e.g., G5.3 or G6.35), but a dedicated G4 socket specifically features a 4.0 mm center-to-center hole spacing.
Related connections
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