Best Circuit Opening Relays of 2026

Robert Reyes Avatar
Robert Reyes
Last Updated: Jan 10, 2026

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Circuit Opening Relays are electrical devices that play a crucial role in ensuring the safety of a vehicle's occupants. These relays are designed to cut off the fuel supply to the engine in the event of a collision or impact, preventing the risk of fire or explosion. They work by detecting the sudden deceleration of the vehicle and sending a signal to the fuel pump to shut down. Circuit Opening Relays are a vital component of any modern vehicle's safety system and are widely used in cars, trucks, and other vehicles around the world.

At a Glance: Our Top Picks

Standard Motor Products RY116T Relay Cover #TOP 1
Standard Motor Products RY116T Relay
ftb score rating icon 9.8
Standard Motor Products RY612 Auto Relay Cover #TOP 2
Standard Motor Products RY612 Auto Relay
ftb score rating icon 9.7
Standard Motor Products RY51 Relay Cover #TOP 3
Standard Motor Products RY51 Relay
ftb score rating icon 9.5

Top 10 Circuit Opening Relays

#TOP 1

Standard Motor Products RY116T Relay

RY116T
White
1 Count (Pack of 1)
Standard Motor Products RY116T Relay Cover
Standard Motor Products RY116T Relay

The Standard Motor Relay is designed to help you control electrical circuits efficiently. It has a compact height of 7.6 centimeters, making it easy to fit into tight spaces. Weighing just 0.59 pounds, this relay is lightweight, which simplifies handling and installation. The product is part of the Standard Motor Products line, known for reliability in circuit opening relays. Using this relay can provide you with dependable performance and convenience when managing your vehicle’s electrical systems.

What We Like
Compact size
Lightweight design
Reliable brand
Efficient circuit control
#TOP 2

Standard Motor Products RY612 Auto Relay

RY612
Oem Replacement
1 Count (Pack of 1)
Standard Motor Products RY612 Auto Relay Cover
Standard Motor Products RY612 Relay, Oem Replacement

The Standard Motor RY612 Relay is a reliable auto part designed to help control your vehicle’s electrical circuits efficiently. This single relay comes in a convenient package weighing just half a pound, making it easy to handle and install. Made in China, it meets quality standards for circuit opening relays, ensuring your car’s electrical system functions smoothly. Whether you need a replacement or an upgrade, this relay offers a practical solution that fits well with your vehicle’s needs.

What We Like
Compact and lightweight
Single unit package
Reliable circuit control
OEM replacement quality
#TOP 3

Standard Motor Products RY51 Relay

RY51
Assorted
1 Count (Pack of 1)
Standard Motor Products RY51 Relay Cover
Standard Motor Products RY51 Relay

The Standard Motor RY51 Relay is a high-quality product designed to meet your circuit opening relay needs. With a fabric content of 100% multi, this relay ensures durability and reliability. Its compact size, measuring 2.89L x 1.49W x 1.0H inches, makes it easy to install in tight spaces. Weighing only 0.2 pounds, it is lightweight and won't add unnecessary bulk to your vehicle. The RY51 Relay is designed to be a single unit, ensuring you have everything you need in one package. Whether you're replacing a faulty relay or upgrading your vehicle's electrical system, the Standard Motor RY51 Relay is the perfect choice.

What We Like
Durable
Compact
Lightweight
#TOP 4

Standard Motor Products SR105 Relay

Standard Motor Products SR105 Relay Cover
Standard Motor Products SR105 Relay

The SMP SR105 Relay is designed to fit conveniently in your vehicle's electrical system. Manufactured in China, this relay offers reliable origin tracing for quality assurance. Its compact size, with a height of about 2.45 inches, a length of 2.55 inches, and a width of 2.51 inches, makes it easy to install in tight spaces without hassle. These dimensions ensure that you can replace or upgrade your circuit opening relay without worrying about fitting issues, giving you a smooth and straightforward installation experience.

What We Like
Compact dimensions
Easy installation
Reliable country of origin
#TOP 5

Standard Motor Products RY31 Relay

Standard Motor Products RY31 Relay Cover
Standard Motor Products RY31 Relay

This Standard Relay is designed for vehicle specific use and produced by Standard Motor Products. It has a compact size of 3.45" L x 1.81" W x 1.44" H, making it easy to install in tight spaces. This relay is ideal for use with Throttle Position Sensors, ensuring they can function correctly and reliably.

What We Like
Compact size for easy installation in tight spaces
Designed for vehicle-specific use
Produced by Standard Motor Products, a trusted brand
#TOP 6

Standard Motor Products RY117 Relay

Standard Motor Products RY117 Relay Cover
Standard Motor Products RY117 Relay

The SMP RY117 Relay is a vehicle-specific circuit opening relay designed to fit your car perfectly. Made in China, this relay ensures reliable performance for your vehicle's electrical system. It weighs just 0.022 pounds, making it lightweight and easy to handle during installation or replacement. With its precise fit and trusted brand, you can count on this relay to help maintain your vehicle’s electrical functions smoothly and efficiently.

What We Like
Vehicle-specific fit
Lightweight design
Reliable brand
Compact size
#TOP 7

Standard Motor Products RY255 Relay

RY255
Assorted
One Size
Standard Motor Products RY255 Relay Cover
Standard Motor Products RY255 Relay

Standard Relay, a product by Standard Motor Products, is a circuit opening relay. Originating from China, it comes in a package that is 4.19 inches high, 9.9 inches long, and 6.19 inches wide. The relay plays a crucial role in controlling electrical circuits, ensuring smooth functioning of your vehicle. With its compact package dimensions, it is easy to store and install, making it convenient for users. The reliable brand ensures quality performance for your automotive needs.

What We Like
Controls electrical circuits
Compact package size
Easy installation
#TOP 8

Standard Motor Products HR-125 Relay

HR-125
Assorted
One Size
Standard Motor Products HR-125 Relay Cover
Standard Motor Products HR-125 Relay Assorted, One Size

The Standard Relay HR-125 is designed to provide reliable circuit opening capabilities. Originating from China, this product features a compact package height of 2.536 inches, making it easy to store or integrate into various applications. With a length of 9.841 inches and a width of 6.774 inches, it is also convenient to handle. These dimensions ensure that the relay can fit into tight spaces while maintaining optimal performance. This relay is an excellent choice for those needing dependable electrical components.

What We Like
Compact size for easy installation
Reliable circuit performance
Convenient packaging dimensions
#TOP 9

Standard Motor Products RY612T Relay

RY612T
Assorted
1 Count (Pack of 1)
Standard Motor Products RY612T Relay Cover
Standard Motor Products RY612T Relay

The Standard Motor RY612T Relay offers a compact design with a height of 2.7 inches, making it easy to fit in tight spaces under the hood. Its length of 5.3 inches ensures it covers enough area for secure installation without being bulky. The width of 3.78 inches adds to its sturdy structure, providing durability and reliability. This vehicle-specific relay is designed to match your car’s needs precisely, giving you a perfect fit and optimal performance. With these dimensions, you can expect a hassle-free installation and reliable operation in your vehicle’s electrical system.

What We Like
Compact size
Vehicle-specific fit
Durable build
Easy installation
#TOP 10

Standard Motor Products HR-106 Relay

HR-106
Assorted
One Size
Standard Motor Products HR-106 Relay Cover
Standard Motor Products HR-106 Relay Assorted, One Size

The Standard Motor Relay is designed for reliable circuit opening applications. It measures 2.536 inches in height, making it compact and easy to fit into various setups. With a length of 9.841 inches and a width of 6.774 inches, this relay is packaged conveniently for storage or transport. Being manufactured in China, it offers a blend of quality and affordability, ensuring you get a dependable product without breaking the bank. This relay is ideal for those who need consistent performance in their electrical systems.

What We Like
Compact size
Convenient packaging
Quality assurance
Affordable option
Buying Guide Image

Frequently Asked Questions (FAQs)

1. How do relays open and close?

Relays function by opening and closing contacts in one electrical circuit to control another circuit. When a relay is not energized, a normally open (NO) contact remains open, and a normally closed (NC) contact remains closed.

2. How does normally open relay work?

Normally open relays default to an open position, meaning there is no contact between the circuits when they are not in use. When power is applied, an electromagnet pulls the first circuit into contact with the second, closing the circuit and allowing power to flow through.

3. What is an example of a normally open relay?

One example of a normally open relay is its use in blower motors. It can be used to delay the operation of a blower motor for a specific period after the activation of the heater unit, ensuring that the air is adequately heated before it is circulated.

4. Do relays fail open or closed?

Electromechanical relays tend to fail in the open position, while solid-state relays have a tendency to fail in a shorted state on their outputs. Although relays can fail in the opposite mode, these are the most common failure scenarios.

5. Why is open relay bad?

An open relay in the context of Simple Transfer Mail Protocol (SMTP) servers is improperly configured and allows unauthenticated relay of email. This can be exploited by spammers who connect to the server and send forged emails using the relay, leading to spam emails being sent.

6. What are the three types of relays?

The three main types of relays are electromechanical relays (EMR), solid-state relays (SSR), and Reed relays.

Editor's Notes

During our circuit opening relay research, we found 24 circuit opening relay products and shortlisted 10 quality products. We collected and analyzed 9,546 customer reviews through our big data system to write the circuit opening relays list. We found that most customers choose circuit opening relays with an average price of $15.77.

The circuit opening relays are available for purchase. We have researched hundreds of brands and picked the top brands of circuit opening relays, including Standard Motor Products and more. The seller of top 1 product has received honest feedback from 384 consumers with an average rating of 4.7.

Written by
Robert Reyes Avatar

Robert Reyes is a dedicated writer from San Francisco with a bachelor of degree in mechanics and a bachelor of degree in marketing. He focuses on making some complicated topics simple and enjoys explaining complex and technical things in an easy-to-understand way.