JCB 4W GU10 Non-Dimmable LED Bulb - Warm White 3000K

The JCB 4W GU10 is a non-dimmable LED spotlight bulb delivering 250 lumens at 3000K warm white. The GU10 twist-and-lock base fits standard UK downlighters, track lights and spotlight fittings without needing a transformer. At 4W consumption the bulb replaces a 35W halogen spotlight, cutting energy use by 91% while providing comparable light output through a 100° beam angle.

Designed for general residential and commercial spotlight installations, the bulb suits living rooms, hallways, kitchens and retail display lighting where downlighters or track spotlights are fitted. The 3000K colour temperature sits in the warm white range, producing a soft yellowish light similar to traditional halogen bulbs. The 100° beam spread provides wide coverage from recessed ceiling fittings, reducing the number of bulbs needed to light a given area compared to narrower 38° or 60° spots.

The bulb measures 50mm diameter and 57mm height, matching the physical footprint of most GU10 halogen bulbs so it sits flush in existing downlighter trims. JCB rates the bulb for up to 10 years' use based on typical domestic operation of 2.7 hours per day. The bulb carries an F energy rating under the revised EU energy labelling scale introduced in 2021, which recalibrated ratings to reflect stricter efficiency thresholds. The non-dimmable design means it operates at fixed brightness on standard on/off switching only and is not compatible with dimmer switches.

Is this bulb dimmable?

No. This JCB GU10 bulb operates at fixed brightness on standard on/off switching only and is not compatible with dimmer switches. Installing it on a dimmer circuit may cause flicker, buzzing or failure. JCB produces separate dimmable GU10 models if dimming is required.

What halogen wattage does it replace?

The 250-lumen output at 4W consumption replaces a typical 35W halogen GU10 spotlight. The 100° beam angle provides wider coverage than many halogen spots, which typically use 38° reflectors.

Will it fit my existing GU10 downlighters?

Yes. The 50mm diameter and 57mm height match standard GU10 halogen bulb dimensions, so the LED sits flush in most downlighter trims and track spotlight fittings. The twist-and-lock GU10 base is a direct swap for halogen GU10s without needing adapters or transformer changes.

What does the F energy rating mean?

The F rating reflects the revised EU energy labelling scale introduced in 2021, which recalibrated ratings to make A-grade harder to achieve. Most LED bulbs that previously carried A+ or A++ ratings now sit at D, E or F under the stricter scale. The bulb still uses 91% less energy than the 35W halogen it replaces.