Brochure
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www.eao.com
Machines covered by the Machinery Directive (2006 / 42 / EC)
must be equipped with at least one emergency stop actua-
tor that can prevent an imminent or occurring hazard.
According to the standards, an emergency stop actuator
must have, among other things, the following:
A red actuator head with yellow background
Unlocking arrows in the same colour as the actuator, i.e.
red, if unlocking happens by rotating the actuator
No symbols or text on the actuator or background (with the
exception of a symbol according to IEC 60417-5638)
Optional yellow label with ISO 13850 symbol
Positive opening contacts
Fool-proof latching
A twist, pull or key to release, although the latter should
be avoided
Why red and not white arrows?
With a twist release, the direction of the twist move must be
visible in accordance with DIN EN 60947-5-5. For this rea-
son, white arrows were often attached on the actuator until
2016. However, these high-contrast white arrows on the red
actuator could be misunderstood as the direction of actua-
tion. To avoid this, DIN EN 13850 states that the unlocking
arrows must be designed with a low-contrast colour that is
preferably identical to the background.
Positive opening and fool-proof security
Contact separation must be a direct result of a movement of
the operating part and must not depend on a spring. For
identication purposes, each positive opening contact is
marked with the following symbol.
All EAO emergency stop devices are tested according to EN
60947-5-1 and EN 60947-5-5 and are suitable for applications
according to DIN EN ISO 13850 and EN 60204 1.
EAO emergency stop devices are always fool-proof. This
means that no contact may open before the mechanical
latching has taken place, but must then open immediately.
The standard describes that the emergency stop device
must not lock without generating an emergency stop signal
(EN 60947-5-5, section 6.2.1. The German version still – as
of 03/2019 – uses the term “EMERGENCY OFF”, but the
English version uses the correct term “Emergency Stop”).
The robust EAO emergency stop switches with positive
opening function (according to DIN EN ISO 13850 and EN
60204-1) are fool-proof. This means that after the release
process has been carried out, the switching element is
safely actuated and the actuator engages. Resetting is pos-
sible only through a deliberate unlocking without restarting
the machine solely by this process. Restarting is made pos-
sible only with the release.
What is the difference between emergency stop and stop switches?
Stop switches do not have to fully comply with the stand-
ards and specications mentioned above and therefore
have a less sophisticated design. For example, they do not
have to be fool-proof, i.e. the contact can open before the
mechanical locking has taken place. The unlocking may
lead to a restart of a machine with the stop switch. This is
why the stop switch is often used as an On/Off button. In
addition, the colours of the actuators do not have to be red
and the background does not necessarily have to be yellow.
Stop switches can also have snap-action switching elements.
A positive opening contact is not mandatory. The EAO stop
switch range offers a wide choice of actuator colours to
meet all design requirements.