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A driver that is wired to the wrong load may flicker, shut down, overheat, or permanently damage the LED module before the fixture is ever put into service. Knowing how to wire an LED driver starts with reading the driver label, not matching wire colors by assumption. Input voltage, output type, current rating, dimming method, and grounding requirements all need to agree with the fixture and the building circuit.

For a simple 120V residential replacement, wiring may be limited to line, neutral, and ground. For commercial high bays, panel lights, signage, strip lighting, or multi-fixture runs, the job can also involve 120-277V input, 0-10V dimming leads, junction boxes, branch-circuit protection, and driver load calculations. If you are not qualified to work on line-voltage wiring, use a licensed electrician.

Identify the LED Driver Before Wiring It

An LED driver converts building power into the controlled electrical output LEDs need. It is not interchangeable with every LED fixture or strip. The label tells you what it can safely operate.

Start by locating the input rating. A driver marked 120V AC is intended for a standard 120V supply. A 120-277V AC driver can operate on common commercial voltages, provided the branch circuit voltage falls within that range. Some products accept 100-347V or 347-480V for larger commercial facilities, but those require compatible supply voltage and installation practices.

Next, identify whether the output is constant current or constant voltage. This is the decision that determines the rest of the installation.

Constant-current drivers

Constant-current drivers are common in recessed downlights, high bays, linear fixtures, flood lights, wall packs, and integrated LED modules. Their labels show output current in milliamps, such as 350 mA, 700 mA, 1,050 mA, or 1,400 mA, plus an output voltage range.

For example, a driver rated at 700 mA with an output range of 24-42V can run an LED load that requires 700 mA and has a total forward voltage within 24-42V. Do not connect a constant-current driver to an LED strip unless the strip is specifically designed for that driver type.

Constant-voltage drivers

Constant-voltage drivers provide a fixed DC output, most often 12V DC or 24V DC. They are standard for LED strip lighting, under-cabinet systems, channel lighting, cabinet lighting, and certain signage applications. The output label may read 24V DC, 96W, 4A.

With constant-voltage products, voltage must match exactly. A 24V strip requires a 24V driver. The driver wattage must also exceed the connected load. For a 72W strip-light run, use a driver rated above 72W. A practical allowance is 20% or more, so a 96W or 100W driver is the better fit when ambient heat and long operating hours are factors.

Turn Off Power and Confirm the Circuit Is Dead

Switch off the correct breaker before opening a junction box or fixture. Then use a properly rated voltage tester to verify that the conductors are de-energized. A wall switch alone is not sufficient protection because the circuit may be miswired, shared, or controlled from another location.

Follow the driver instructions, fixture wiring diagram, National Electrical Code requirements, and local electrical rules. Make all splices inside an approved electrical box or fixture compartment. Do not leave wire nuts, lever connectors, or exposed conductor connections above a ceiling, inside a wall cavity, or outside without a listed enclosure.

Commercial installers should also confirm that the branch circuit has the correct breaker size and that the fixture, driver, controls, and mounting hardware are listed for the application. Wet-location flood lights, canopy lights, and exterior wall packs need wiring methods and enclosures suitable for the environment.

How to Wire an LED Driver on the Input Side

The input side connects to the building's AC power. Driver leads are commonly labeled LINE or L, NEUTRAL or N, and GROUND, GND, or a ground symbol.

In typical US wiring, connect the building's black hot conductor to the driver's black line lead. Connect the building's white neutral conductor to the driver's white neutral lead. Connect the green or bare copper equipment grounding conductor to the driver's green ground lead or grounding screw.

Wire colors are common conventions, not a substitute for verifying labels. In commercial buildings, hot conductors may be black, red, blue, orange, brown, or another color based on system voltage and phase. Always identify conductors at the source and follow the driver marking.

A Class 2 LED driver may have separate line-voltage input leads and low-voltage output leads. Keep those systems separated. Do not route low-voltage LED output wiring in the same manner as line-voltage conductors unless the wiring method and equipment are specifically approved for it.

Connect the LED Output Correctly

The output side is usually marked LED+, LED-, V+, V-, or with red and black leads. With DC output, polarity matters. Connect positive output to positive LED input and negative output to negative LED input.

For 12V or 24V LED strip lighting, connect the driver's V+ terminal or red lead to the strip's positive pad, and V- or black lead to the negative pad. Use wire gauge appropriate for the run length and current. Long low-voltage runs can develop voltage drop, causing dimmer light at the far end of the strip. A larger conductor, shorter run, or multiple power-feed points may be necessary.

For constant-current fixtures, follow the fixture manufacturer's specified LED connection method. Some integrated fixtures arrive with quick-connect plugs between the driver and LED board. Do not cut or alter a listed connector unless the product instructions permit it.

Never connect LED outputs in parallel or series simply because the wiring appears physically possible. Series wiring changes total forward voltage. Parallel wiring can create uneven current sharing. Both methods must be designed around the exact driver and LED specifications.

Wire Dimming Leads Only When the System Matches

Many commercial LED drivers include extra low-voltage control wires. Purple and gray leads are commonly used for 0-10V dimming. Purple is typically DIM+ and gray is DIM-. These wires connect to a compatible 0-10V dimmer or lighting control, not to 120V line voltage.

If the installation does not use dimming, cap each dimming lead separately according to the driver instructions. Do not tie purple and gray together unless the manufacturer specifically directs that method. Incorrectly joining control leads can prevent dimming or damage the driver.

Some drivers use different control systems, including TRIAC or phase-cut dimming, ELV, MLV, DALI, PWM, or proprietary smart controls. A driver may be dimmable without being compatible with every dimmer. Confirm both the driver dimming type and the control's load compatibility before ordering or installing.

Check Load, Heat, and Location Before Energizing

Before restoring power, inspect every connection for exposed copper, loose terminals, damaged insulation, and incorrect polarity. Confirm that wire connectors are sized for the conductor count and gauge. Ensure the driver is secured and has adequate airflow.

Driver heat is normal, but excessive heat shortens service life. Do not bury a non-rated driver in insulation, seal it inside an unventilated cavity, or mount it directly against materials that exceed its temperature rating. For LED tape installations, choose a driver with the correct IP rating if it will be exposed to moisture, dust, or outdoor conditions.

For multi-fixture commercial projects, calculate the total fixture load, confirm circuit capacity, and plan access for future driver service. A remote driver that cannot be reached without opening finished walls or ceilings creates unnecessary maintenance cost later.

Common LED Driver Wiring Problems

A fixture that does not turn on may have no line voltage, a reversed or open output connection, an incompatible dimmer, or a driver whose protection circuit has tripped. Flickering often points to a dimmer mismatch, loose neutral, overloaded driver, voltage drop, or failing LED load.

If an LED strip is bright near the driver and noticeably dim at the far end, inspect voltage drop before replacing the driver. If a constant-current fixture cycles on and off, verify that the LED module falls within the driver's voltage range and that the fixture is not overheating.

Choose drivers and fixtures with the ratings your project requires. For commercial work, that may include 120-277V input, 0-10V compatibility, damp- or wet-location suitability, and UL, ETL, or DLC listings where applicable. LED Plus supports replacement and project purchases across drivers, strip lighting, commercial fixtures, and installation components, including bulk-order needs.

A correctly wired driver should disappear into the job: stable output, predictable dimming, safe connections, and light that performs at its rated level every day.