What is a GU10 socket?

GU10 is the standard push-and-twist socket for spots on 230 volts: two thick pins with a thickened end, which you push into the holder and turn a quarter turn. No transformer needed, and the lamp is separately replaceable.

How to recognize it

Twist the lamp out of the holder and look at the base. On a GU10 you see two sturdy pins with a knob on the end, about 10 mm apart — hence the 10 in the name. That knob is what holds it in place when you turn.

Do not confuse it with these two:

• GU5.3 or MR16 — two thin, straight pins with no thickened end, 5.3 mm apart. That runs on 12 volts and needs a transformer or driver.
• G9 — two thin loops you push straight into the holder without turning. Small, and mostly found in wall lights.

Why GU10 is used so widely

Two reasons. It runs directly on mains voltage, so there is no transformer above your ceiling. And the light source is separate, so if you want to change the color or the brightness, you screw in a different lamp without touching the fixture.

That also makes it the safest choice in the long run. A fixture with an integrated LED goes in the bin when the LED gives out; with a GU10 fixture you replace only the lamp.

What we carry with GU10

It is the most common socket in the range. Ten products have GU10 with the light source not included, seven have GU10 with a light source, and another ten fixtures carry two or three GU10 sockets.

Among the recessed spotlights:

• Plano — GU10 or MR16, Ø80 mm, IP22, €9.95
• Privo — GU10 or MR16, Ø68 mm, IP65, €11.95
• Luma — GU10 or MR16, Ø72 mm, €12.95
• Feno — GU10 or MR16, Ø80 mm, €10.95

And beyond those: the Faro surface-mounted spot (€14.95, tiltable), the Divo up-and-down wall light with two GU10s (€15.95) and track spots such as the Rilo for single-circuit track (€14.95).

Watch out: fixtures that say "GU10 / MR16"

Four of our spots say GU10 or MR16. That means the holder can take either, but not both at once and not without thought. Choose MR16 and you are still on 12 volts and therefore need a driver. Choose GU10 and you connect straight to 230 volts. In practice almost everyone picks GU10, precisely to avoid that driver.

You buy the lamp separately

With fixtures stating that the light source is not included, there is no lamp in the box. That is deliberate: you choose the light color, the number of lumens and whether it has to dim. We do not currently stock loose GU10 lamps, so you buy those elsewhere.

When buying, watch three things: lumens, Kelvin and the word dimmable. Put a non-dimmable lamp on a dimmer and it will flicker — see Why does your LED lamp flicker?

Heat is the thing to watch

A GU10 lamp sits in a closed housing, and that is exactly where cheap lamps come unstuck. The LED itself does not get hot, but the electronics in the base do, and in a sealed spot that heat has nowhere to go. That is why a lamp that lasts for years in an open fixture gives out after a year in a recessed spotlight.

So check whether the lamp is suitable for enclosed fixtures; that is usually on the packaging. And stay within the maximum wattage of the fixture. On a spot with two or three GU10 sockets, such as the Largo series, the consumption of all the lamps adds up.

GU10 or integrated

The counterpart is a fixture with a fixed LED inside, such as the Lesto. That is usually flatter, has a CCT switch and a driver matched to the fixture. Which of the two suits you is covered in GU10 or integrated LED: what should you choose? All the GU10 fixtures are in the recessed spotlights collection.