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Entry type: FAQ Entry ID: 23159133, Entry date: 11/24/2017

Are EMERGENCY STOP buttons with protective collars approved for 3SU1 / 3SB EMERGENCY STOP mushroom pushbuttons in accordance with DIN EN ISO 13850?

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This article provides information on whether protective collars for EMERGENCY STOP mushroom pushbuttons are approved in accordance with DIN EN ISO 13850.


Do the protective collars from the 3SU1 / 3SB program comply with standards (e.g. DIN EN 60204-1), work guidelines and EC directives?
Is there an EC type-examination certificate?
Are protective collars approved in the USA?




EMERGENCY STOP devices with protective collars are mentioned in section 4.5 of DIN EN ISO 13850:2016.  It is therefore at the discretion of the particular expert whether or not to accept the EMERGENCY STOP. The switchgear standard only requires that the EMERGENCY STOP should be freely accessible.

If the expert does not accept the EMERGENCY STOP button with the protective collar, the only option remaining to the machine manufacturer is to use an EMERGENCY STOP button without a protective collar (e.g. 3SU1 / 3SB3). Protective collars are not allowed in the printing industry for example, but in other industries they are.

The protective collar is not included in the EC directives, which is why there is no type-examination certificate.

There are no statements concerning the protective collar either in DIN EN 60204-1 / IEC 60204-1 or in the USA.
In this case, DIN EN ISO 13850 would be relevant (when this standard was created, the chairman was an American). The protective collar was mentioned for the first time in section 3.7 of DIN EN ISO 13850:2016
This describes a mechanical measure which is provided to reduce the possibility of unintended actuation of the EMERGENCY STOP device.

Excerpt from section 4.5 of DIN EN ISO 13850.
"The use of a protective collar (shroud) around the emergency stop device should be avoided, except when necessary to prevent unintended actuation and other measures are not practicable."

In order to increase plant availability, the choice of a location other than that of the protective collar might be an option. This would be preferable to the protective collar.

The above statement is additionally justified by the opinions of NA 060-48-02 AA (national mirror committee of the ISO 13850 standard) in July 2017 and DIN EN ISO 13850:2016 Section 4.5.
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