What's the Difference Between a Safety Relay and an Ordinary Relay?

Safety relays and normal relays are distinct devices designed for different applications and with specific characteristics. Here are the key differences between them:

specific characteristics Safety Relay Normal Relay
Functions Safety relays include various functions such as switching, indication, and protection. They are designed to continuously monitor hazardous processes and detect even minor irregularities to ensure safety. Normal relays are mainly used for basic switching and may not have the extensive protective and monitoring features of safety relays
Function and Application A safety relay is primarily used to implement security functions. It is designed to ensure the safety of individuals and machinery by monitoring and controlling safety-critical processes. Safety relays are used in applications where failure could lead to harm or injury, such as emergency stop systems, safety gates, and safety light curtains A normal relay, also known as a general or common relay, is an electrically operated switch used for controlling a high-power circuit with a low-power signal. It is commonly employed in control circuits for various purposes, such as switching loads, signaling, and automation
Size Safety relays tend to be larger in size compared to normal relays. Their larger dimensions are due to the advanced circuitry and components required to ensure safety functions. Normal relays come in smaller sizes as they are primarily used for basic switching within control circuits. Their compact design is suitable for general control applications.
Contact Structure Safety relays are equipped with force-guided contacts, including locked, positive, or captive-guided contacts. These contacts ensure that the relay operates reliably, especially in the event of contact welding or fusion. The design is focused on minimizing the risk of contact failure. Normal relays typically employ electrically conductive metal contacts for basic switching operations. They lack the force-guided contacts found in safety relays.
Color Safety relays are often designed in a specific color, typically yellow. This distinctive color makes them easily recognizable and helps identify their role in safety applications. Normal relays are not typically associated with a specific color and are often found in standard colors like white.
Dimensions Safety relays have larger dimensions, such as 17.5 mm, 22.5 mm, etc., to accommodate the necessary safety features and circuitry. Normal relays have smaller dimensions, making them more compact and suitable for general control applications.
Cost Safety relays are generally more expensive than normal relays due to their specialized safety functions and additional features. Normal relays are typically more cost-effective as they are used in a wide range of general control and switching applications
Applications Safety relays are commonly used in safety-critical applications where the protection of individuals and machinery is paramount. They are essential for ensuring compliance with safety standards and regulations Normal relays find their application in a broad spectrum of automation and control systems, where safety considerations are not the primary focus.
  • safety relays and normal relays differ in terms of their size, contact structure, color, dimensions, functions, cost, and application.
  • Safety relays are specialized for safety-critical applications and come with enhanced safety features, while normal relays are versatile devices used for general control and switching tasks.
  • Understanding the distinctions between these two types of relays is crucial for selecting the appropriate relay for a given application.