Australia runs on more bulb fittings than almost any market, because we inherited British bayonet caps and then imported European screw fittings on top. So the bulb aisle has four common caps, they're not interchangeable, and every household eventually buys the wrong one. Here's the two-minute identification guide.
How do I tell which cap my light takes?
| Cap | How to spot it | Where you'll find it |
|---|---|---|
| B22 (bayonet) | Two pins, push and twist | Older Australian ceiling fittings, standard lamps |
| E27 (large screw) | Screw thread, ~27 mm wide (a $2 coin is close) | Pendants, larger fittings, most modern imports |
| E14 (small screw) | Screw thread, ~14 mm, noticeably slim | Wall lights, chandeliers, decorative fittings |
| G9 (pins) | Two looped pins, tiny capsule bulb, push straight in | Compact designer fittings, some sconces |
The E numbers are literally the thread diameter in millimetres, named after Edison. If the old bulb is gone and you can't measure, photograph the empty socket next to a coin and any lighting shop can identify it instantly — or email us the photo at hello@battii.com.au.
Why do wall lights so often take E14 or G9?
Space. A wall light's body is a fraction of a pendant's, and the smaller caps let designers keep fittings compact. Most fittings in our wall light range take E14 or G9 for exactly this reason — the cap type is listed on every product page, so you can buy globes in the same run.
Which numbers matter more than the cap?
Once the cap fits, two specs decide whether you'll like the light:
Lumens — brightness. Forget watts; LED wattage tells you power draw, not output. For a wall light, 250–500 lumens per fitting covers most ambient jobs.
Colour temperature — 2700K warm white for living spaces, full stop. The kelvin number is on every box, and it changes the feel of a room more than the fitting does. We've covered it properly in the warm vs cool white guide.
Third, quietly important: if you have dimmers, the box must say "dimmable." Non-dimmable LEDs on a dimmer circuit flicker, buzz, and die young.
Can you use adapters between caps?
B22-to-E27 adapters and similar exist and work, but they add length and sit the bulb lower or prouder than the fitting was designed for — visible on an open wall light, invisible inside a big pendant shade. On decorative fittings, buy the right cap instead.
Are old incandescent and halogen bulbs still around?
Being phased out, and not worth chasing. Quality LEDs now match halogen's warmth (look for 2700K and a CRI of 90+), draw a tenth of the power, and run cool — which matters inside stone and fabric fittings, where bulb heat used to be a real constraint.
E27 vs B22: what's the difference?
E27 and B22 are the two most common caps in Australia, and they are not interchangeable. E27 is a screw fitting that twists into a threaded socket, about 27 mm across. B22 is a bayonet: two pins on the side that push in and twist a quarter turn to lock. If your socket has a spiral thread you need E27; if it has two slots you push and twist into, you need B22. The same bulb shapes and brightness are sold in both caps, so you only need to match the cap.
E14 vs E27: what's the difference?
Both are screw caps, so the only real difference is size. E14 is 14 mm across, the slim candle cap used in wall lights, chandeliers and smaller decorative fittings. E27 is 27 mm, the standard large screw cap for pendants and bigger fittings. An E14 bulb will not hold in an E27 socket, and the reverse is also true. Wall lights most often take E14 or G9, so check the fitting before buying globes.
Frequently asked questions
What is the difference between E14 and E27?
Thread width: E14 is 14 mm, E27 is 27 mm. E14 is the slim "candle" cap common in wall lights and chandeliers; E27 is the standard large screw cap.
Is B22 the same as E27?
No. B22 is a push-and-twist bayonet with two pins; E27 is a screw thread. Same bulb sizes, incompatible caps.
What is the difference between E27 and B22?
E27 is a screw cap that twists into a thread; B22 is a bayonet cap that you push in and twist a quarter turn. They are not interchangeable, but the same bulbs are sold in both, so match your socket.
Which bulb cap do wall lights usually take?
Most wall lights take E14 (small screw) or G9 (twin-pin capsule), because the smaller caps keep the fitting compact. The cap type is listed on every Battii product page.
What does a G9 bulb look like?
A small capsule, usually 4–6 cm long, with two looped pins underneath. It pushes straight in without twisting.
How many lumens should a wall light bulb be?
250–500 lumens per fitting for ambient use. Higher for reading lights, lower for pure mood lighting.
