Are xenon headlight conversions legal?

Can I replace the standard headlights on my Vauxhall Astra Elite with xenon versions? I have seen a number of conversion kits for sale. Are they legal?

DN, Brechin, Angus

High-intensity discharge (HID) headlights, better known as xenon lights, offer more pure white light on the road than standard halogen bulbs while drawing less power. However, installing xenon bulbs as an aftermarket upgrade, as opposed to having them fitted on the production line as standard, is not legal in the eyes of the transport department. It says you must change the whole headlamp unit, because the lens and reflector for a halogen bulb will give the wrong beam pattern if used with an HID bulb.

The Driver and Vehicle Standards Agency, for its part, publishes a raft of safety regulations that all gas-discharge headlights must adhere to. For instance, they must be fitted with a washing system (unless the output is less than 2,000 lumens) and an automatic self-levelling system (unless it can be proved that the dipped beam is aimed correctly, as tested in the MoT). They must also be set up so that the dipped beam stays on when the main beam is activated.

You’d be better off upgrading to “performance bulbs”, high-grade versions of your existing ones that put twice as much illumination onto the road both legally and much more cheaply — they are typically £20-£30 a pair.

Remember that if you change your lighting in any way, you will need to inform your insurer.

INSPECTOR GADGET
Dave Pollard has written several Haynes manuals and has tested just about every car-related accessory – read more from Dave here.

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