Emergency stop switch

Also known as emergency push buttons or mushroom switches, this type of device is distinguished by its characteristic red mushroom-shaped head. This distinctive design makes them easily identifiable and quick to activate during emergencies. Both professionals and personnel can therefore react instantly to potential hazards.

These safety switches are utilised across numerous industrial sectors. Environmentally conscious solutions provide optimal protection while respecting environmental standards. Each manufacturer offers options tailored to specific operational requirements.

What is the role of an emergency stop switch?

The primary function of an emergency stop switch is to immediately interrupt the operation of an electrical installation. This safety device cuts off the electrical or pneumatic power supply to hazardous machinery. It simultaneously protects both the operator and equipment from industrial accidents.

Unlike other automatic protection devices, this type of push button requires direct human intervention. The operator must manually activate the button to trigger the emergency stop function. This design ensures a deliberate response to danger identified by the user.

These emergency push buttons can be installed on various industrial machines: conveyor systems, presses, lathes, and milling machines. Each installation therefore benefits from protection tailored to its specific risk profile. The device ensures a clean and definitive disconnection of the main electrical circuit.

European standards impose a strict colour code for these safety components. Each button must feature a red actuator on a yellow background for immediate identification. This standardisation facilitates recognition by all operators on control panels.

How do you activate an emergency stop switch?

An emergency stop switch is activated by simply pressing the red mushroom-shaped head. The push button locks in the depressed position after being struck with a fist or palm. This design prevents accidental machine restart.

These electrical safety buttons are generally equipped with three types of reset mechanisms. The 'twist-to-release' system requires the red button head to be rotated clockwise. The 'key release' system requires a specific key to unlock and restart the machine. The 'push-pull' mechanism allows the button head to be unlocked by pulling it outward.

Key-operated models offer enhanced security in sensitive industrial environments. Only authorised personnel can restart the installation after technical intervention. This feature prevents unauthorised restarts and ensures proper maintenance procedures are followed.

Some buttons incorporate built-in LED indicators to signal their activation status. These visual aids help locate equipment that has been shut down in complex control installations. Operators can quickly identify the area affected by the emergency stop on the main control panel.

How to wire an emergency stop switch?

Connecting an emergency stop switch requires specific wiring with an undervoltage or shunt release coil. This MX or MN coil connects directly to the circuit breaker or main protective device. The control circuit typically uses a 2A Type C circuit breaker for protection.

The installation varies depending on the type of coil used in the assembly. The MX coil operates on applied voltage and trips the device when energised. The MN coil operates on voltage loss and causes the electrical circuit to open when de-energised.

The wiring must comply with safety standards to ensure reliable operation of all components. Each connection must be inspected and tested before industrial commissioning. Qualified personnel must verify circuit continuity and ensure all terminals are properly tightened.

Manufacturers like Schneider with its Harmony range and Legrand with IMO offer complete solutions. Their enclosures include all components necessary for assembly and electrical connection. These products simplify installation while ensuring compliance with safety standards.

They can be panel-mounted (flush installation) or surface-mounted on walls. IP-rated enclosures allow installation outdoors or in harsh environments with appropriate environmental protection. Each configuration meets specific environmental requirements depending on the industrial application.

What is the difference between a stop button and an emergency stop switch?

A standard stop button allows machinery to be stopped normally according to a programmed shutdown sequence. It initiates a controlled shutdown procedure that may take several seconds to complete. This type of switch protects equipment and prevents mechanical damage.

The emergency stop switch causes an immediate halt without any prior shutdown sequence. This abrupt disconnection may potentially damage equipment but prioritises personnel safety above all else. Its use is reserved for genuine emergency situations.

Physical appearance is also a major distinguishing factor between these two types of controls. The emergency button must feature an easily identifiable red mushroom head as mandated by safety standards. Conventional stop buttons are available in various shapes and colours depending on their specific function.

The wiring also differs significantly between these two control systems. The emergency stop directly interrupts the main power supply via a trip coil mechanism. Normal stop functions typically use contactors for gradual, controlled shutdown of the installation.

Maintenance and reliability

Maintenance of this equipment requires regular inspections to ensure operational reliability. Functional tests verify that each component in the circuit operates correctly. This preventive maintenance ensures the availability of these critical safety devices when needed.

The Harmony range from Schneider and Osmoz from Legrand offer comprehensive selections of components. These manufacturers provide solutions suited to every industrial or commercial application. Their products comply with international standards and guarantee optimal switching reliability.

Our permanent inventory ensures rapid delivery of all essential safety equipment. Have questions? Please consult our technical team, who will assist you in selecting the appropriate products for your projects. We provide guidance on applicable standards and best practices for installing industrial control devices.