A 24V work light is a high-output task lamp designed for vehicles with a 24-volt electrical system. A 24V system runs on 2 batteries wired in series and is standard fitment on commercial trucks (HGVs), heavy plant (large excavators, dump trucks, articulated dumpers), agricultural sprayers above 200hp, and most military vehicles. Running a 12V lamp on a 24V system burns the bulb out in seconds. Running a 24V lamp on a 12V system produces less than half its rated output. The voltage match is the first specification to verify before any other consideration. This guide covers the vehicles that use 24V systems, the difference between 24V-only and dual-voltage 12V/24V lamps, the wattage and beam patterns suited to 24V applications, the IP rating requirements, and the wiring rules for adding 24V work lights to a vehicle.
What a 24V Work Light Is
A 24V work light is a vehicle-mounted task lamp engineered for a nominal 24-volt direct current supply. The actual voltage on a 24V system ranges from 23V (engine off, battery rested) to 28V (engine running, alternator charging). A 24V work light must tolerate this range without burning out or dimming.
A 24V LED work light contains an LED driver circuit that regulates the input voltage to the constant current required by the LED chips. The driver accepts a wider input voltage than a basic 12V driver. A 24V halogen work light uses a halogen bulb rated specifically for 24V operation, with a different filament resistance from the equivalent 12V bulb. A 24V xenon (HID) work light uses a 24V ballast that strikes the arc and maintains the gas discharge at 24V input.
The terminology varies by supplier. Some specify “24V only” lamps that run only on a 24V supply. Others specify “12-24V” or “10-30V” lamps that accept any voltage in that range. The dual-voltage option matters for mixed fleets that run some 12V tractors and some 24V trucks.
Which Vehicles Use 24V Systems
A 24V electrical system is standard on commercial vehicles, heavy plant, and selected large agricultural machinery. The voltage choice reflects the higher current demand on these vehicles: a 24V system delivers the same power as a 12V system at half the current, which means smaller cables, lighter alternators, and better cold-cranking on diesel engines.
| Vehicle type | Voltage | Examples |
|---|---|---|
| Commercial HGV | 24V | DAF, Scania, Volvo, Mercedes Actros, MAN |
| Bus and coach | 24V | All UK-built buses and coaches |
| Heavy plant | 24V | CAT D6, CAT D8, Volvo A40, Komatsu PC500 |
| Large excavators | 24V | CAT 320, JCB JS220, Hitachi ZX350 (above 20 tonnes) |
| Articulated dumpers | 24V | Volvo A30, Bell B30, CAT 730 |
| Compact excavators | 12V | CAT 305, JCB 8025, Kubota KX (below 5 tonnes) |
| Wheel loaders (large) | 24V | CAT 980, Volvo L150, JCB 437 |
| Telehandlers (most) | 12V | JCB 535, Manitou MLT, Merlo Turbofarmer |
| Compact tractors | 12V | Kubota BX/B/L, John Deere 1 family, Iseki TM |
| Utility tractors | 12V | New Holland T6, JD 6R, Massey 5700 |
| Large tractors (above 200hp) | 12V or 24V | JD 8R, Fendt 1000, NH T9, Case Magnum |
| Combine harvesters | 12V (most) or 24V (heavy duty) | NH CR, JD S700, Claas Lexion |
| Self-propelled sprayers (large) | 12V or 24V | Agrifac Condor, John Deere 4940 |
| Military vehicles | 24V | All NATO-spec wheeled and tracked vehicles |
A modern utility tractor below 200hp almost always uses 12V. A modern heavy truck or large plant machine almost always uses 24V. The crossover sits in the large agricultural tractor category and the medium plant category, where specification varies by manufacturer and model.
Checking Your Vehicle Voltage
A vehicle voltage is shown on the battery casing, the vehicle handbook, and the chassis VIN plate. Two batteries wired in series (positive of one to negative of the other) usually indicates 24V; a single battery usually indicates 12V. Two batteries wired in parallel (positive to positive) indicates 12V with extra capacity. A multimeter reading across the main battery terminals confirms the voltage: approximately 12.6V indicates a 12V system at rest, approximately 25.2V indicates a 24V system at rest.
Dual-Voltage 12V/24V Work Lights
A dual-voltage work light accepts any voltage from 10V to 30V (some up to 60V) and operates correctly across the entire range. The lamp contains a wide-input LED driver that regulates the output current regardless of input voltage. The output (lumens) stays consistent at 12V, 18V, 24V, and 28V input.
Dual-voltage lamps are the dominant LED specification in the UK market because they suit mixed fleets and remove the inventory complexity of stocking separate 12V and 24V SKUs. A typical specification reads “10-30V DC” or “12-32V DC”. The price premium over a fixed 12V or fixed 24V lamp is small (5 to 15% in most ranges).
Why Dual-Voltage Makes Sense for Most Buyers
A dual-voltage work light moves with the operator. A contractor running a 12V tractor and a 24V truck can fit the same magnetic-mount lamp to both vehicles without rewiring. A farmer running a 12V combine and a 24V articulated dumper can keep a single stock of spare lamps. A plant operator switching between machines maintains 1 lamp specification across the fleet.
The dual-voltage approach also future-proofs the purchase. A buyer who replaces a 12V utility tractor with a 24V large tractor keeps the existing lamps. A buyer who adds a 24V truck to a previously 12V-only fleet adds the truck without replacing the lighting stock.
Wattage and Output for 24V Work Lights
A 24V work light wattage rating is the power draw in watts. The output (lumens) is the visible light produced. The relationship between watts and lumens varies by technology and by lamp quality.
| Wattage | LED output (lumens) | Halogen output (lumens) | Typical application |
|---|---|---|---|
| 18W | 1,600 to 2,400 | 380 (12V) / 380 (24V) | Compact tractor work lamp |
| 27W | 2,400 to 3,600 | 575 (24V) | Standard utility work lamp |
| 40W | 3,600 to 5,200 | 850 (24V) | Truck and large tractor work lamp |
| 60W | 5,400 to 7,800 | 1,275 (24V) | Heavy plant work lamp |
| 80W | 7,200 to 10,400 | 1,700 (24V) | Premium plant and HGV work lamp |
| 120W | 10,800 to 15,600 | n/a (LED only at this wattage) | Heavy excavator, dump truck |
| 180W | 16,200 to 23,400 | n/a (LED only) | Heavy mining, off-road racing |
The wattage to lumens ratio differs widely between cheap and premium LEDs. A cheap 40W LED might produce 3,000 lumens; a premium 40W LED with Cree or Osram chips produces 5,000 lumens or more. The cheap vs premium LED work lights guide covers the quality tier differences.
Current Draw at 24V vs 12V
A 24V work light draws half the current of an equivalent 12V work light at the same power. A 40W lamp on 24V draws approximately 1.7A; the same 40W lamp on 12V draws approximately 3.3A. The reduced current allows thinner wiring, smaller fuses, and lower voltage drop across long cable runs.
For an HGV with cab-roof work lamps wired back to a fuse box near the front, the 24V supply allows the wiring run without significant voltage drop on 1.5mm² cable. For a 12V equivalent, the same run would need 2.5mm² or 4mm² cable to avoid voltage drop at the lamp.
Beam Patterns for 24V Applications
A 24V work light is most often fitted to a vehicle where the operator works in different positions to a tractor or compact machine. A truck operator works at the rear cargo area; a plant operator works around the bucket, the boom, or the dump body; a sprayer operator works ahead of the boom. The beam pattern matches the work position.
A flood beam suits truck cargo loading (illuminating a wide area immediately behind or beside the vehicle). A spot beam suits long-range visibility for HGV reversing into yards and for excavator bucket positioning at distance. A combo beam (flood plus spot) suits self-propelled sprayer booms where the operator needs both the boom edge and the area ahead of the boom illuminated. See work light beam patterns for the full beam pattern reference.
Truck-Specific Beam Considerations
A truck work lamp mounted on the cab roof or the rear top edge needs a flood beam to cover the cargo area below. A driving lamp mounted on the front bumper needs a spot beam to extend high-beam reach on unlit motorways. A reverse lamp on the rear chassis needs a wide spread beam (often 100 to 120 degrees) to cover the area immediately behind the vehicle for yard manoeuvring.
Plant-Specific Beam Considerations
A heavy excavator work lamp mounted on the boom needs a focussed flood beam to illuminate the bucket position at 5 to 10 metres ahead of the cab. A wheel loader work lamp mounted on the cab roof needs a wide flood beam to cover the loading area. An articulated dumper work lamp needs a long-throw spot beam to see ahead at speed on a haul road.
IP Rating for 24V Heavy-Duty Use
A 24V work light fitted to a truck, HGV, or heavy plant machine must tolerate harsher conditions than a typical tractor work lamp. Pressure washing is more aggressive on commercial vehicles. Vibration is higher on plant. Mud and debris ingress is constant on construction sites.
The minimum IP rating for a 24V work light fitted to plant or HGV use is IP67 (dust-tight, water-immersion to 1 metre for 30 minutes). The preferred specification is IP69K (dust-tight, high-pressure jet washing at 80°C). The IP67 vs IP69K guide covers the difference and which use cases need IP69K.
A plant operator who pressure-washes the machine daily needs IP69K-rated lamps. A truck driver who relies on a fixed jet wash bay at a depot needs IP69K. A long-distance HGV that only sees occasional motorway service-station washing can specify IP67 and accept the lower price.
Wiring 24V Work Lights
A 24V work light wiring run uses the same principles as 12V wiring but with reduced current and the option for thinner cable. A relay is still recommended for any work lamp drawing more than 10A continuous, because routing the full current through a dashboard switch shortens switch lifespan.
Basic Wiring Schematic
A basic 24V work light wiring run includes a 24V supply tapped from the fuse box, a 15A blade fuse in line with the supply, a 5-pin relay (30, 85, 86, 87, 87a), a switched 24V signal from the dashboard or ignition, and a return earth to the chassis. The relay coil draws approximately 100mA; the main contacts switch the work lamp current. See how to wire work lights to a 12V system with a relay for the equivalent 12V schematic; the 24V schematic is identical except for the supply voltage and the lower current rating on the cabling.
Fuse Sizing for 24V Work Lights
A 24V work lamp fuse sizes at approximately 125% of the continuous current draw. A 40W lamp drawing 1.7A on 24V sizes to a 3A fuse for a single lamp or a 5A fuse for 2 lamps in parallel. A pair of 80W lamps drawing 3.4A each (6.8A total) sizes to a 10A fuse. Most blade fuses are 5A, 10A, 15A, 20A, and 30A; round up to the next standard size.
Avoiding 12V/24V Cross-Connection
A 12V work light connected accidentally to a 24V supply burns out in seconds. A 24V work light connected accidentally to a 12V supply produces approximately one-quarter of its rated output (and may not strike at all on xenon types). The fix is clear labelling at the supply point, a visual check of the lamp specification before connection, and (for mixed-fleet operators) the deliberate specification of dual-voltage 10-30V lamps.
Common 24V Work Light Mistakes
A common 24V work light mistake is ordering a 12V lamp for a truck and burning it out within seconds of switching on. The cost is the lamp price plus the lost installation labour. The fix is verifying the vehicle voltage before ordering.
A second common mistake is fitting a high-wattage lamp without uprating the wiring. A 24V system tolerates more wattage per cable cross-section than 12V, but a 150W LED lamp still draws 6.3A and needs at least 1.5mm² cable on a short run or 2.5mm² on a long run.
A third common mistake is fitting lamps directly to the cab roof of a glass-fibre or fabric-roofed plant cab without a steel bracket. The mounting point loosens, the lamp swings out of position, and the wiring chafes against the roof material. The fix is a proper steel mounting bracket bonded or bolted through the cab roof.
Buying 24V Work Lights in the UK
A 24V work light is available through agricultural lighting specialists, commercial vehicle parts suppliers, and plant machinery dealers. The dual-voltage 10-30V specification is the most widely stocked because it covers both 12V and 24V applications.
For 24V applications on UK trucks, large tractors, sprayers, and plant, the typical buying pattern is: dual-voltage 10-30V LED work lamps for general use, IP69K-rated lamps for high-pressure wash environments, 40 to 80W lamps for most applications, and matched-pair purchasing so left and right beam outputs are equal.
For the wider work light buying decision, see the work light buyer’s checklist and the work light wattage guide. For 12V applications, see 12V LED work lights. For premium options, see best LED work lights for tractors in 2026.
Agri Lighting holds UK stock of LED work lights across the dual-voltage 10-30V range from 18W to 180W output. Same-day dispatch applies to orders placed before 3pm. Browse the LED work lights range for current stock.