B22 BA15 Bayonet Lamp Base — B22d B15d B15s Bayonet Cap Socket
B22 & BA15 Bayonet Lamp Bases — B22d, BA15d & BA15s Cap Sockets for LED, CFL & Halogen Bulbs
The B series bayonet lamp base is the standard lamp socket in the United Kingdom, Australia, India, Hong Kong, and most Commonwealth countries, as well as widely used in automotive, marine, and indicator lighting worldwide. Unlike Edison screw bases, bayonet bases use a push-and-twist locking mechanism with two side pins, providing a more secure connection resistant to vibration and accidental loosening. The "B" designation indicates bayonet cap, followed by the diameter in millimeters: B22 (22mm, standard household) and BA15 (15mm, miniature automotive/indicator).
B Series Size & Contact Reference Guide
- B22d — 22mm bayonet, double contact (two bottom contacts). The standard household lamp base in the UK, Australia, India, and Commonwealth countries for 240VAC. Used with standard A-shape, GLS, and decorative bulbs.
- BA15d — 15mm bayonet, double contact. Standard automotive and indicator lamp base (also called BAY15d or 1157 in North America). Used in automotive tail/brake lights, marine navigation lights, and industrial indicator lamps.
- BA15s — 15mm bayonet, single contact (one bottom contact). Standard automotive single-filament lamp base (also called BAU15s or 1156 in North America). Used in automotive turn signals, reverse lights, and single-function indicator lamps.
Key Technical Specifications
- Materials: Ceramic (high-temperature, for halogen), phenolic (standard, for LED/CFL), plastic (low-cost, for LED)
- Rated voltage: 250V AC (B22d household) / 12–24V DC (BA15 automotive)
- Rated current: 4A (B22d) / 5A (BA15d/BA15s)
- Mounting: Panel mount (with nut and bushing), wire leads, or snap-in
- Certifications: CE, RoHS
Complete Product Range in This Collection
This collection includes: B22d standard bayonet bases (ceramic and phenolic, panel mount with nut, wire leads, and pendant configurations), BA15d double-contact miniature bayonet bases (panel mount, wire leads, snap-in for automotive and indicator applications), and BA15s single-contact miniature bayonet bases (panel mount, wire leads, snap-in). All available in multiple mounting configurations for OEM luminaire assembly and repair.
Ideal Applications
- B22d: Standard household pendant lights, table lamps, and ceiling fixtures in UK/Australia/India/Commonwealth markets; LED and CFL retrofit lamp sockets; OEM luminaire manufacturing for Commonwealth export markets
- BA15d: Automotive tail/brake combination lights (dual-filament equivalent); marine navigation and anchor lights; industrial panel indicator lamps; traffic signal indicator lamps
- BA15s: Automotive turn signal, reverse, and single-function indicator lights; motorcycle and scooter lighting; industrial single-function indicator lamps; low-voltage decorative lighting
Bayonet Lamp Base Buying Guide
Step 1 — Identify B22 vs BA15: B22 (22mm diameter) is the large household standard. BA15 (15mm diameter) is the miniature automotive/indicator standard. Measure the diameter of the bayonet cap on your existing bulb to confirm.
Step 2 — Single vs double contact (BA15s vs BA15d): BA15d has two bottom contacts for dual-function lamps (e.g., tail + brake). BA15s has one bottom contact for single-function lamps (e.g., turn signal only). Check your application's wiring before ordering.
Step 3 — Choose material: Ceramic bases are required for halogen bulbs (high heat). Phenolic bases are suitable for LED and CFL. For automotive BA15 applications, phenolic or plastic bases rated for 12–24V DC are standard.
Step 4 — Choose mounting style: Panel mount (with threaded bushing and nut) for fixture installation. Wire leads for hardwired pendant and automotive installations. Snap-in for automotive lamp holders in pre-formed housings.
Why Choose Yoeruyo for B Series Lamp Bases?
Yoeruyo stocks the complete B series bayonet lamp base range — B22d household, BA15d double-contact, and BA15s single-contact — in ceramic, phenolic, and plastic materials with multiple mounting configurations. All products are CE and RoHS certified. Available from 10pcs for repair to 500pcs+ for OEM production. Custom configurations available on request.
Frequently Asked Questions
Q: What countries use B22 bayonet lamp bases?
A: B22 is the standard household lamp base in the United Kingdom, Australia, New Zealand, India, Hong Kong, Singapore, Malaysia, South Africa, and most Commonwealth countries. It is not commonly used in North America (which uses E26) or continental Europe (which uses E27).
Q: What is the difference between BA15d and BA15s?
A: BA15d (double contact) has two bottom contacts and is used for dual-function lamps (e.g., combined tail and brake light). BA15s (single contact) has one bottom contact and is used for single-function lamps (e.g., turn signal or reverse light). They are not interchangeable.
Q: Can B22 bases be used for LED bulbs?
A: Yes. Phenolic and plastic B22 bases are suitable for LED bulbs. Ceramic bases are compatible with all bulb types. Ensure the base is rated for the voltage of your electrical system (250V for 240VAC mains).
Q: Are BA15 bases suitable for 12V automotive applications?
A: Yes. BA15d and BA15s bases are the standard for 12V and 24V automotive lamp applications. Ensure the base material and contact rating are appropriate for your vehicle's electrical system.
Q: What is the difference between B22 and E27?
A: B22 uses a bayonet push-and-twist locking mechanism (two side pins). E27 uses a screw thread. They are not interchangeable. B22 is standard in Commonwealth countries; E27 is standard in Europe, Asia, and most of the world.
