H7 Bulbs Explained: 477, 499, Equivalents and LED Rules in Ireland
In this guide
An H7 bulb is a single-filament halogen headlight bulb on a PX26d base with 2 connector pins. The standard 12-volt H7 is rated 55 watts and gives about 1,500 lumens. On the trade number system used by UK bulb brands it is sold as the 477, and some brands use 499. The 24-volt version is rated 70 watts. Each H7 gives one beam only, so a headlamp usually needs one H7 for dipped and another for main beam.
This guide explains what the H7 code means, the PX26d base, the 12V and 24V ratings and trade numbers, where H7 bulbs are used on tractors and road vehicles, what people really mean by an “H7 equivalent”, where LED H7 bulbs stand under Irish rules and the NCT, and how to fit one.
What Is an H7 Bulb?
An H7 is a halogen filament lamp category defined in UNECE Regulation 37. It has one filament inside a quartz glass capsule filled with halogen gas, and it has no shield cap. The headlamp’s reflector or projector lens, not the bulb, shapes the light into either a dipped beam with a sharp cut-off or a long main beam.
Because the bulb only does one job, makers can tune the optics around a single filament in a fixed position. That gives a precise beam, which is why the H7 spread through car headlamps from the 1990s onwards and appears in many newer tractor, telehandler and loader headlamps.
| Specification | H7 12V | H7 24V |
|---|---|---|
| Trade number | 477 (also sold as 499) | 474 (Ring numbering) |
| Wattage | 55W | 70W |
| Light output | 1,500 lumens | 1,750 lumens |
| Base | PX26d | PX26d |
| Filaments | 1 | 1 |
| Connector pins | 2 | 2 |
The light output figures are the reference values in Regulation 37, which allows a tolerance of plus or minus 10 percent. Some makers quote a lower figure for their standard H7 (one major maker lists 1,350 lumens), so compare bulbs within the same brand rather than across brands.
The PX26d Base
The PX26d is a prefocus base with a flat metal flange and a locating tab, so the bulb only seats in the headlamp one way. That fixes the filament at the exact point the optics were designed around. A wire spring clip or a retaining ring holds the flange against the headlamp, and the 2 flat pins on the back take a 2-way connector: one feed and one earth.
The PX26d base is not shared with the other common headlamp bulbs. The H4 uses a P43t base with 3 pins, the H1 uses a P14.5s base and the H11 uses a PGJ19-2 base with an L-shaped plastic body. None of them fits an H7 headlamp correctly.
477, 499 and 474: The Trade Numbers
- 477 is the most widely used trade number for the 12V 55W H7, sometimes with a prefix such as R477.
- 499 is used by some brands for the same 12V 55W H7 bulb. A 477 and a 499 marked H7 12V 55W are the same bulb. Ring uses R499 for a different, off-road H1 bulb, so check for the H7 marking.
- 474 is Ring’s number for the 24V 70W H7, used on lorries, plant and 24V tractors. Other brands may simply label it H7 24V.
Because the numbers vary by brand, the safest check is the printing on the base: H7, the voltage and the wattage. A 12V bulb on a 24V machine blows almost at once, and a 24V bulb on a 12V machine gives a weak yellow light. See 12V vs 24V lighting systems if you are not sure which you have.
What H7 Bulbs Are Used For
- Dipped beam headlamps in twin-bulb headlamps, often behind a projector lens.
- Main beam headlamps, either in the same housing as the dipped beam or as a separate lamp.
- Tractor, telehandler and loader headlamps on many newer machines that use separate dipped and main beam units.
- Front fog lamps and some auxiliary and work lamps built around an H7.
Check the old bulb rather than going by model, because the same machine range can change headlamp type during production. The comparison with the twin-filament bulb used in single-bulb headlamps is in H4 vs H7 bulbs, and other halogen types are set out in halogen headlamp bulb types.
What Is an H7 Equivalent?
There is no other bulb type that is a direct equivalent of an H7. The only correct replacement for an H7 is another H7 of the right voltage. When someone asks for an “H7 equivalent”, they usually mean one of 4 things, and each has a different answer.
A different brand or part number
Any bulb marked H7 with an E or e mark and the right voltage and wattage is an equivalent, whatever the brand or the country of approval. The 477 and 499 numbers are the same bulb. This is the normal answer.
A brighter or longer-lasting H7
Uprated H7 bulbs sold as +50%, +100% or +150% are still H7 55W bulbs and are road legal when E-marked and fitted to a headlamp designed for H7. The percentage refers to the light at a point in the beam, not total output, and these bulbs often have a shorter life. Long-life H7 bulbs trade some brightness for more hours. Both are true H7 equivalents. For longer intervals between changes, see our lifetime halogen bulbs.
A different bulb code that looks similar
H1, H3, H11 and other single-filament halogens are not H7 equivalents. They have different bases, filament positions and connectors, so they will not seat correctly and cannot give a correct beam even if adapted. High-wattage “H7” bulbs of 80 or 100 watts are sold for off-road use only and are not approved for the road.
An LED “H7 equivalent”
LED bulbs with an H7 base are often sold as H7 equivalents. RSA guidance says an LED bulb is only legal if it is type-approved, fitted to a compatible vehicle and does not dazzle, and unapproved or incompatible conversions fail the NCT (see the next section). Most LED H7 bulbs on sale are not approved, so they are not an equivalent for road use in Ireland.
Are LED H7 Bulbs Legal in Ireland?
The RSA guidance on HID and LED lights sets out the Irish position. Retrofit LED and HID bulbs are not always compatible with the vehicle or the headlamp. An LED bulb is legal only if it is type-approved, fitted to a compatible vehicle, and its beam does not dazzle. A car fails the NCT if it has an unapproved kit, an approved kit fitted to an incompatible vehicle, or HID bulbs retrofitted into ordinary halogen headlamps. Commercial vehicles are checked the same way at the CVRT, where any fitted lamp must work correctly.
In 2025 the first LED replacement bulb approved under Regulation 37 was launched in the H11 category. At the time of writing no LED replacement bulb is approved for H7 under Regulation 37. Some LED H7 bulbs have national approval in other European countries for a list of specific vehicles, but that does not make them suitable for every headlamp, and an LED H7 in an unlisted vehicle is exactly the “approved kit on an incompatible vehicle” case the RSA describes. Treat any “road legal LED H7” claim with caution and check current RSA or NCTS guidance before fitting one.
Ordinary tractors (design speed 40 km/h or less) do not need a periodic test, and fast tractors only need a CVRT test when used for non-exempt work. But the lighting regulations still apply on the road: no lamp may dazzle or mislead other traffic (Road Traffic (Lighting of Vehicles) Regulations 1963, Art. 48), and an LED bulb in a reflector built for a filament can throw light above the cut-off. The compliant route to LED headlights is a complete E-marked LED headlamp. The options are explained in LED headlamp conversions, and you can browse tractor headlights.
How to Fit an H7 Bulb
- Switch off the lights and ignition, and turn off the battery isolator on a tractor.
- Reach the back of the headlamp. On many tractors this means lifting the bonnet or removing a grille or headlamp cover.
- Pull off the 2-pin connector and remove the dust cover.
- Release the spring clip or turn the retaining ring, and lift out the old bulb, noting which way the locating tab sits.
- Check the code and voltage on the old bulb: H7 12V 55W or H7 24V 70W.
- Hold the new bulb by its metal flange or plastic base only. Do not touch the glass, because skin oils create hot spots that shorten its life.
- Seat the bulb with the tab in the slot so the flange sits flat, then refit the clip.
- Refit the dust cover so it seals all the way round, then the connector.
- Test the beam. If both headlamps use H7 for dipped beam, replace both bulbs together so the colour and brightness match.
If you do touch the glass, wipe it with isopropyl alcohol on a lint-free cloth before switching on. Shop standard halogen bulbs for 12V and 24V H7 replacements, with free delivery to Ireland on orders over €150. If your headlamp has one bulb for both beams, you need the twin-filament bulb in H4 bulbs explained.
Frequently asked questions
Is a 477 bulb the same as an H7?
Yes. H7 is the ECE category and 477 is the most common trade number for the 12V 55W version. Some brands use 499 for the same bulb.
What is the equivalent of an H7 bulb?
Only another H7. Any E-marked H7 of the same voltage from any brand is an equivalent, including uprated and long-life versions. Other codes such as H1 or H11 do not fit, and RSA guidance says unapproved or incompatible LED bulbs in halogen headlamps fail the NCT.
Is an H7 12V 55W the standard bulb?
Yes. 55 watts is the standard rating for a 12V H7. The 24V version is 70 watts. Bulbs rated 80 or 100 watts are off-road only.
Can I use an H4 instead of an H7?
No. The H4 has 2 filaments, a P43t base and a 3-pin connector, so it does not fit an H7 headlamp.
Why do my H7 bulbs keep blowing?
Common causes are touching the glass during fitting, water getting past a split dust cover, a loose connector, vibration and high charging voltage. Check those before fitting another bulb.
