A C Capacitor Wiring Diagram

Hello and welcome to our article on A C Capacitor Wiring Diagram. In this comprehensive guide, we will provide you with detailed information and step-by-step instructions on how to properly wire a capacitor for your air conditioning unit. Whether you are a DIY enthusiast or a professional technician, this article will help you understand the wiring process and ensure the optimal functioning of your A C unit.

1. Understanding the Capacitor

Before we delve into the wiring diagram, let’s first understand the role of a capacitor in an air conditioning system. A capacitor is an electrical component that stores and releases electrical energy. In A C units, capacitors are used to provide an extra boost of power to the compressor and fan motors during startup.

Capacitors come in different types and sizes, but the most common ones used in A C units are run capacitors and start capacitors. Run capacitors are designed to continuously provide a steady flow of electrical energy to the motors, while start capacitors provide an extra burst of power during startup.

2. Safety Precautions

Before starting any electrical work, it is important to prioritize safety. Make sure to turn off the power supply to your A C unit at the circuit breaker before proceeding with the wiring process. Additionally, use insulated tools and wear protective gloves to avoid any electric shocks.

3. Gathering the Required Materials

Before you begin wiring the capacitor, gather all the necessary materials. This includes a capacitor of the appropriate size and type for your A C unit, wire strippers, wire connectors, electrical tape, and a multimeter for testing continuity.

4. Locating the Capacitor

The capacitor is typically located inside the control panel of your A C unit. Open the panel and locate the capacitor, which is a cylindrical or oval-shaped component with two or three terminals.

5. Identifying the Capacitor Terminals

Identify the terminals on the capacitor. Most capacitors have three terminals labeled as “C” (common), “FAN” (for the fan motor), and “HERM” (for the compressor motor). If your capacitor has only two terminals, it will be labeled as “C” and “HERM.”

6. Disconnecting the Old Capacitor

If you are replacing an old capacitor, make sure to disconnect it from the power supply and the wires connected to it. Take a picture or make a note of the existing wiring configuration to ensure proper connection of the new capacitor.

7. Wiring the New Capacitor

Start by connecting one end of a wire to the “C” terminal of the capacitor. Strip the insulation off the other end of the wire and connect it to the common terminal of the contactor, usually labeled as “C” or “COM.”

Next, connect the wire from the “FAN” terminal of the capacitor to the fan motor terminal on the contactor. Finally, connect the wire from the “HERM” terminal of the capacitor to the compressor motor terminal on the contactor.

8. Testing the Wiring

Once you have completed the wiring, use a multimeter to test the continuity of the connections. Set the multimeter to the resistance or continuity mode and touch the probes to the corresponding terminals on the capacitor and contactor. The multimeter should display a reading close to zero, indicating a proper connection.

9. Alternative Wiring Options

While the above wiring diagram is the most common method for wiring a capacitor in an A C unit, there are alternative options available depending on the specific requirements of your system. It is always recommended to refer to the manufacturer’s instructions or consult a professional technician for guidance on alternative wiring configurations.

10. A C Capacitor Wiring Diagram Table

Terminal Description
C Common terminal
FAN Terminal for fan motor
HERM Terminal for compressor motor


In conclusion, wiring a capacitor is a crucial step in ensuring the proper functioning of your A C unit. By following the steps outlined in this article and adhering to safety precautions, you can successfully wire a capacitor and avoid any potential electrical issues. Remember to consult a professional technician if you are unsure or need assistance. Enjoy the cool comfort provided by your efficiently wired air conditioning system!

Frequently Asked Questions

Q: Can I use a capacitor with different microfarad (µF) rating?

A: It is important to use a capacitor with the same microfarad (µF) rating as specified by the manufacturer. Using a capacitor with a different rating can potentially damage the motors and result in inefficient operation of your A C unit.

Q: How often should I replace the capacitor in my A C unit?

A: Capacitors have a limited lifespan and can degrade over time. It is recommended to have the capacitor inspected and tested by a professional technician during regular maintenance visits. If any signs of wear or malfunction are detected, the capacitor should be replaced promptly.

Q: Can I wire the capacitor without professional assistance?

A: Wiring a capacitor requires a good understanding of electrical systems and safety precautions. If you are not confident in your abilities or have limited knowledge in this area, it is best to seek professional assistance to ensure a proper and safe wiring installation.