How Do Emergency Stop Switches Work?

Made to be vibrant in color to be highly identifiable, emergency stop switches and buttons are essential for the safety they provide to operators using machinery, especially during instances of misuse or an accident. Serving as a fail-safe mechanism when equipment cannot be shut off in its typical manner, these devices come in many forms and are often applied to machines among public, commercial, and industrial facilities.

Regularly referred to as an emergency stop (E-stop) switch, emergency off (EMO) switch, emergency power off (EPO) switch, and kill switch, among others, E-stops that are commonly integrated into systems include latching key release, latching pull release, and latching turn release types. Named after their mode of actuation, each switch must follow certain actions to effectively activate. For example, an E-stop with a latching key release demands the insertion of a key to be able to push down the actuator, while those with a latching pull release just need to be pressed to stop operations. Meanwhile, E-stops with a latching turn release can be pressed, but have to be twisted or unscrewed to release the actuator.

Subject to standard rules and regulations based on the country in which an emergency off system is installed, not all machinery may require a safety switch; however, their implementation should always be considered to promote safety when working near potentially hazardous equipment. To first determine the risk a machine poses to individuals in a particular envirovent, a risk assessment should always be done, and from there, the appropriate E-stop can be chosen. In addition, a kill switch can be found anywhere within vehicles like trains, high-performance automobiles, and watercraft, alongside industrial machinery, machine tools, fuel stations, elevators, military equipment, software, and much more.

A part of an overall emergency stop system, an E-stop mechanism will immediately halt particular equipment it was designated to when actuated. Although, in lieu of proper part shutdown, it will abort all current processes, even if such actions will damage the equipment. As they can be used by pedestrians and engineers depending on their situational application, they are made to contrast with their environment to be easily noticed, that way quick action can be taken when necessary. Additionally, for global standardization and identification, the International Electrotechnical Commission specifies that safety control components incorporate a telltale mushroom head (button) for safe and reliable operation with a single hand.  

To ensure that a safety switch is not accidently activated, most also incorporate a protective covering made from plastic or glass known as a mollyguard. When a plastic covering is present, it can easily be rotated open with the help of a mechanical hinge. On the other hand, if shielded by glass, the barrier must be broken to access the kill switch; therefore, in such places where glass shields are used, they will necessitate debris cleanup and prompt replacement as exposed glass shards will be present and pose a hazard. 

When aging emergency switches and other push button parts demand routine replacement, you can always find the proper emergency stop buttons you need to safely continue operations here at Sourcing Streamlined. A part of the ASAP Semiconductor family of websites, we are home to an inventory of over 2 billion new, used, obsolete, and hard-to-find products. Moreover, we operate with AS9120B, ISO 9001:2015, and FAA AC 00-56B accreditation, ensuring that all procured items are authentic and ready for implementation upon their arrival. We invite you to pursue our product catalogs at your leisure, and upon identifying items of interest, take advantage of our Instant RFQ service to receive a comprehensive quote for your comparisons—all within 15 minutes or less! 


November 2, 2022

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