Switch & button
Emergency stop / emergency stop switch
Everything you need to know about emergency stop switches
Obvious and positioned centrally: The requirements for an emergency stop switch or emergency stop button are clearly defined. Whether it is designed to quickly shut down machines, technical systems or a vehicle: It must be easy to activate and robustly designed. We provide information about which form is best suited for the respective use and what the differences are between the individual models.
Table of contents:
How does an emergency stop switch work?
In case of danger, emergency stop switches and emergency stop buttons ensure that accidents are minor and can save lives. They ensure that machines, tools or vehicles are not damaged further if a defect occurs.
Emergency stop switches are buttons that are manually activated and which trigger a signal which in an emergency should quickly and reliably switch off machines and systems or make them safe. If the emergency command is triggered, the emergency stop switch locks in the pressed position.
In principle, there is a difference between three stop categories, for which an emergency stop switch is used:
- Stop category 0: Immediately disconnects the energy supply to the drive elements of a machine. The prerequisite is that no danger occurs as a result of the sudden stop.
- Stop category 1: Pressing the emergency stop button switches the running machine, a motor or an electric tool to a safe state. Only then is the energy supply disconnected.
- Stop category 2: Motors or machines are made safe without the energy supply being disconnected. This category is used, for example, on cranes with lifting electromagnets, which must not drop a suspended load as a result of an emergency stop.
What must an emergency stop switch look like?
Whether an aluminium emergency stop button, an emergency stop button in housing or an emergency stop button for areas with strict hygiene requirements: The buttons – like all models from Schlegel – usually have a red knob and are mostly installed on a yellow base. The signal colours ensure that it is clearly visible in the workshop. Some models, such as the emergency stop button with anti-lock collar from Schlegel Elektrokontakt, can also be individually labelled. This simplifies the allocation to specific devices and can be sensible depending on the work area.
What types of emergency stop switches are there?
Emergency stop switches and emergency off switches are characterised by their simple operation. Depending on the model they are designed as a push button or shock switch. The important thing is that the button is shock-proof, locks when activated and can be unlocked again after an incident. To this end, several methods and designs have become established, with which an emergency stop switch is returned to its original state according to EN ISO 13850:
- Emergency stop switches with key
- Emergency stop switch with rotary mechanism
- Emergency stop switch with pull mechanism
- In addition, there are also emergency stop switches with covers to protect against dust or with a protective collar to protect against accidental activation.
When does a machine need an emergency stop?
Apart from portable machines / electric tools, it must be possible to shut down every stationary machine (e.g. lathe, circular saw) quickly and by pressing on an emergency stop switch.
So that its function is guaranteed at all times, the emergency stop switch must be checked once a year. In addition, the following applies: An emergency stop switch should not be seen as a substitute for other safety measures such as safety goggles or shoes with steel toecaps, but instead serves as a supplement in order to increase safety at the workplace or in vehicles. Important to remember: the emergency stop function must always be guaranteed irrespective of the machine's respective operating mode. In addition, all components connected to a machine must be deactivated upon shut-down because the emergency stop button has been pressed.
What is the difference between emergency stop and emergency off?
Explained according to VDE 0113-1, the emergency stop function is by definition a procedure which brings a movement to a stop, which prevents danger due to this movement.
By comparison, the emergency off serves to prevent risks from electric voltage and to disconnect the entire system from the power supply. An emergency off switch is therefore frequently found in laboratories or in the area of distributor systems.
EMERGENCY STOP = shut-down in an emergency
EMERGENCY OFF = switch-off in an emergency