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How do I Wire a 3 Phase HVAC Unit?

Three-phase electric heating, ventilating, and air conditioning (HVAC) units receive power from three live circuits of alternating currents. Wiring a three-phase HVAC unit varies depending if it's a four wire unit or a five wire unit, some have a neutral wire, but many units do not have a neutral wire. The cable colors can vary by manufacturer of the HVAC unit but in general they use black, red, blue and green.

  1. Connect the black wire from the HVAC unit to line one of the electric panel. Secure it in place with a screwdriver. If your unit does not have a black wire use the brown wire.

  2. Connect the red wire from the HVAC unit with line two of the electric panel. Secure it in place with a screwdriver. If your unit does not have a red wire use the orange wire.

  3. Connect the blue wire from the HVAC unit with line three of the electric panel. Secure it in place with a screwdriver. If your unit does not have a blue wire use the yellow wire.

  4. Connect the green cable to the ground. The ground is the green screw on the electric panel. Secure it in place with the screwdriver.

  5. Connect the white cable to the neutral cable from the electric panel. Secure in place with the screwdriver. Most three-phase systems do not have a neutral if this is the case then just tighten the screw in place.

About the Author

Louis Gutierrez began writing in 2010 for various websites, specializing in real estate, construction and electronics. He has over 10 years experience running and operating various successful businesses in these fields and holds a Bachelor of Arts in business administration, graduating magna cum laude from Florida International University.