How do I change an oven bulb?

This is not the same job as changing a lamp in a light fitting. The bulb has to survive 250 to 300°C, the cover is often seized by baked-on grease, and the holder sits inside a cavity you cannot see the back of. The bulb itself is cheap and available; the technique is entirely about the cover.

Safety

What you'll need

• A replacement oven lamp rated to 300°C, matching cap type and wattage
• Rubber gloves or a rubber jar opener, for grip on the cover
• A dry cloth
• Warm soapy water to soften baked-on grease around the cover (optional)

Step by step

1. Isolate the oven and let it cool completely.Switch off at the cooker isolator on the wall, or unplug it. Do not rely on the oven's own off position. Cold means cold — several hours after a roast, not twenty minutes.
2. Identify the lamp you need before you take anything apart.The rating plate or the manual gives it. The common ones are a G9 halogen capsule and a small Edison screw E14, both rated to 300°C, typically 15 to 40W. Buy the oven-rated part; a standard bulb of the same fitting fails in days and can shatter.
3. Soften the grease around the cover first.Baked-on fat around the rim is what makes the cover feel seized. A cloth wrung out in hot soapy water, held against it for a few minutes, does more than force will.
4. Turn the glass cover anticlockwise with grip, not force.A rubber glove or a rubber jar opener spreads the load across the whole cover. Gripping the edges with fingertips is what cracks them. Some covers are a bayonet quarter turn rather than a screw thread — if a quarter turn frees it, stop turning.
5. Remove the old lamp the way its cap works.A G9 halogen capsule pulls straight out of its two-pin socket — pull, do not twist. An E14 screw lamp unscrews anticlockwise. If the glass has separated from the cap, isolate at the consumer unit before gripping the remaining metal.
6. Fit the new lamp without touching the glass.Handle a halogen capsule with the cloth or the packaging. Skin oil on the quartz creates a hot spot that shortens its life dramatically — this matters more on an oven lamp than on any household bulb.
7. Refit the cover, and check the seal is in place.Many covers have a heat-resistant sealing ring. It keeps steam and fat off the lamp and holder. Finger tight plus a nudge; over-tightening is the other way covers crack.
8. Restore power and test.Switch the isolator back on and press the lamp button, or open the door. If the new lamp does not light, the fault is the holder or the switch rather than the bulb, and that is an engineer job because the holder is a mains component set into the cavity wall.

Tips

• Buy two. Oven lamps live a hard life and the second one saves a repeat trip when the first goes.
• If the cover will not move at all, a wide strip of duct tape stuck across it and used as a handle sometimes gives the leverage that fingers cannot.
• On some ovens the lamp is behind a cover accessed only with the shelf runners removed. Take the runners out first rather than working around them.
• A lamp that keeps failing quickly usually means steam is getting past a perished cover seal. Replace the seal as well as the lamp.

Common mistakes

• Fitting an ordinary household bulb of the same cap — It is not rated for cavity temperatures. It will fail quickly and can shatter inside the oven, which turns a five-minute job into clearing glass out of a cavity you cook in.
• Working on a warm oven — The cover and the lamp hold heat far longer than the air does, and the burn happens through the glove you thought was enough.
• Relying on the oven's own controls to isolate it — The lamp circuit on many ovens is live whenever the appliance is supplied, regardless of the function dial. The wall switch or the plug is the isolation.

Questions people ask