8 Pin Relay Wiring Diagram

Hello readers, welcome to our article on the 8 pin relay wiring diagram. In this comprehensive guide, we will discuss the various aspects of wiring an 8 pin relay. Whether you are an electrical enthusiast or a professional, this article will provide you with all the necessary information you need to know about 8 pin relay wiring. So, let’s dive right in!

1. Understanding the Basics

Before we delve into the wiring diagram, let’s first understand the basics of an 8 pin relay. A relay is an electromechanical device that is used to control electrical circuits by using a low-power signal. It acts as a switch that can turn on or off a circuit, based on the input it receives. The 8 pin relay, as the name suggests, consists of eight pins that are used for various connections.

Advantages of 8 Pin Relay Wiring

The 8 pin relay wiring offers several advantages:

  1. Flexibility: The multiple pins allow for versatile wiring options.
  2. Reliability: Relays are known for their durability and long lifespan.
  3. Easy to install: The standardized pin configuration simplifies the installation process.
  4. Wide application: 8 pin relays are used in various industries, including automotive, industrial automation, and HVAC systems.

Disadvantages of 8 Pin Relay Wiring

While there are many advantages, it’s important to consider the drawbacks as well:

  1. Complexity: Wiring an 8 pin relay can be complicated, especially for beginners.
  2. Space requirements: The size of the relay may not be suitable for tight spaces.
  3. Cost: Compared to simpler relay types, 8 pin relays can be more expensive.

2. Pin Configuration

The pin configuration of an 8 pin relay is as follows:

Pin Number Description
1 Coil
2 Normally Open (NO) Contact
3 Normally Closed (NC) Contact
4 Common Contact
5 Coil
6 Normally Open (NO) Contact
7 Normally Closed (NC) Contact
8 Common Contact

3. Wiring an 8 Pin Relay

Now, let’s discuss the step-by-step process of wiring an 8 pin relay:

  1. Identify the coil pins (1 and 5) and connect them to the power source.
  2. Connect the normally open (NO) contact pins (2 and 6) to the circuit you want to control.
  3. Connect the normally closed (NC) contact pins (3 and 7) to the power source.
  4. Connect the common contact pins (4 and 8) to the load you want to control.

4. Alternative Wiring Options

While the above wiring method is the most common, there are alternative options available. One alternative is using a diode across the coil pins to suppress back electromotive force. This protects the circuit from voltage spikes that can occur when the relay switches off. Another alternative is using a flyback diode to achieve the same purpose.

5. Frequently Asked Questions (FAQ)

Q: Can I use an 8 pin relay for high-current applications?

A: Yes, 8 pin relays are suitable for high-current applications as they can handle up to a certain ampere rating. However, it’s important to check the datasheet of the specific relay to ensure its compatibility with your requirements.

Q: How can I test if an 8 pin relay is functioning properly?

A: To test the functionality of an 8 pin relay, you can use a multimeter to measure the continuity of the contacts. Apply power to the coil pins and check if the contacts switch accordingly.

Q: Can I use an 8 pin relay in both AC and DC circuits?

A: Yes, 8 pin relays are designed to work with both AC and DC circuits. However, it’s crucial to select the appropriate relay for the specific circuit type to ensure optimal performance.


In conclusion, the 8 pin relay wiring diagram is a crucial aspect of understanding how to control circuits using relays. We have discussed the basics of an 8 pin relay, its advantages and disadvantages, pin configuration, wiring options, alternative methods, and answered some frequently asked questions. By following the guidelines provided in this article, you can effectively wire an 8 pin relay for various applications. Remember to refer to the datasheet of your specific relay for detailed information on its capabilities and limitations. Happy wiring!