Wire A Metal Halide Lamp

Metal halide lamps are a part of the High Intensity Discharge (HID) family of lighting. These types of lamps include sodium-based lights and mercury vapor lighting. Sodium-based lights can be recognized as the yellow glow of street lamps to the bright white light of the mercury vapor. Regardless of the bulbs, all of these HID lights have a built in transformer that offer a multiple voltage electrical connection. The single-phase transformers with multiple taps, wires, are quickly wired by following a few basic procedures. Does this Spark an idea?


1. Remove the electrical power from the circuit you are going to install the new light fixture. The feeder voltage circuit can be either a 480-volt alternating current (VAC), a 277 VAC, 240 VAC or a 120 VAC.

2. Hang the light fixture using the factory provided method by the manufacturer. There are many types of fixtures and each manufacturer will have their own method for supporting the light fixture from a high ceiling.

3. Remove the wire connector make up box cover with the Philips screwdriver by pulling the single screw out of the screw hole. Place the small screw in your pocket so you do not lose it.

4. Pull all of the transformer tap wires from the connector make up box. Note the small print on the wires that identify the voltages. In most of all cases, the 277 VAC wire will already be stripped back and ready to connect. The 277 VAC is the most common voltage for HID lighting.

5. Strip back the wire insulation on the following wires. The wire insulation should be stripped back one inch exposing the bare copper wire, using the wire strippers. The black, white and green power feed wires and the wires in the light fixture labeled common and the green fixture wire. Do not strip back the identified voltage wire for the light fixture at this time.

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6. Connect the wires by twisting them together with the wire pliers and then cover that connection with a wire nut in the following order. The white power feed wire to the light fixture wire labeled common. Then connect the green power feed wire to the green wire of the light fixture.

7. Identify the power feed voltage source that will energize the light fixture. If the voltage source is 277 VAC, then connect the black wire using the same method in step 6. Replace the box make up cover and the fixture is ready. If a different voltage source is provided continue to step 8

8. Insulate the exposed end of the 277 VAC wire with a wire nut to protect the light fixture from electrically shorting out. Find the correct transformer tap wire for the electrical feed voltage.

9. Strip back the insulation of the correct tap wire as in step 5 and twist together the black power feed wire using the wire pliers. Insulate the connection with a wire nut and replace the makeup box cover.