QTX 400W UV Black Light Bulb E40 - 365nm High Pressure

The QTX 400W UV black light bulb is a high-pressure mercury vapour lamp with an E40 Edison screw fitting, designed to produce ultraviolet light at a peak wavelength of 365nm. At 400W output on 230V mains, the bulb delivers sufficient UV intensity to cover medium to large stage areas, club dancefloors and event spaces where fluorescent materials, paints, fabrics and stage props need to be made visible under black light.

The bulb requires an E40 mogul-base lampholder and a compatible ballast to regulate current and voltage during operation. Once warmed up (typically 3-5 minutes), the 365nm UV output causes fluorescent and phosphorescent materials to glow brightly while rendering non-UV-reactive surfaces nearly invisible in a darkened environment. This effect is widely used in nightclubs, theatrical productions, haunted attractions, and themed events where visual drama depends on selective illumination.

The high-pressure mercury arc inside the bulb generates significant heat during operation, so adequate ventilation around the fitting is essential. The bulb should be handled with gloves when cool, as oils from skin contact can create hot spots on the quartz envelope that shorten bulb life. The E40 fitting provides a secure mechanical connection and can handle the thermal load of sustained 400W operation. Average rated life depends on operating hours and thermal management, but typical high-pressure UV bulbs in this class deliver 2,000-5,000 hours before output drops below usable levels.

This bulb is sold as a replacement lamp for compatible QTX and AVSL UV fixtures, or as a standalone component for custom UV installations where an E40 socket and appropriate ballast are already in place. It is not a general lighting product and emits minimal visible light. Its output is almost entirely in the ultraviolet spectrum, which is invisible to the human eye but highly effective at activating fluorescent pigments.

Does this bulb need a ballast?

Yes. High-pressure UV bulbs require a ballast to regulate current and voltage during ignition and operation. The bulb will not function if connected directly to mains power without a compatible ballast rated for 400W UV lamps.

How long does the bulb take to reach full output?

High-pressure mercury vapour UV bulbs typically take 3-5 minutes to warm up and reach stable UV output. During this period the light may flicker or appear dim until the arc stabilises.

Can this bulb be used in standard light fittings?

No. The E40 fitting is a mogul-base screw much larger than standard E27 household lamp fittings. The bulb also requires a ballast and produces almost no visible light, making it unsuitable for general illumination.

What safety precautions apply?

UV light at 365nm can cause eye strain and skin irritation with prolonged direct exposure. Avoid looking directly at the bulb when lit. Ensure adequate ventilation to dissipate heat, and handle the bulb with gloves when installing or removing to prevent skin oils from contaminating the quartz envelope.