What is ISO 13850？| HBAN Push button

For machinery manufacturers operating in Germany and across the European Union, compliance with EN ISO 13850 is essential for CE marking and machine safety approval. This comprehensive guide explains emergency stop function requirements, integration into safety systems, and how to ensure your emergency stop switch meets EU regulatory standards.

What Is EN ISO 13850?

EN ISO 13850 – Safety of machinery — Emergency stop function — Principles for design

This European standard specifies the functional and design requirements of emergency stop systems. It applies to the entire emergency stop function, not only the switch device.

Objectives of the Emergency Stop Function

• Stop dangerous movements as quickly as possible
• Avert or reduce existing hazards
• Prevent further damage

The emergency stop is defined as a complementary protective measure. It does not replace safeguards such as interlocking systems, protective guards, or safety PLCs.

Emergency Stop Requirements Under EN ISO 13850

1. Clearly Identifiable Actuator

• Red mushroom head actuator
• Yellow background plate
• High visibility
• Easily accessible location

2. Self-Latching Mechanism

The emergency stop switch must mechanically latch when pressed and remain in the stop position until manually reset. Automatic reset is strictly prohibited.

3. Manual Reset Only

• Twist-to-release
• Key-release (application-specific)

Resetting must not automatically restart the machine. A separate start command is required.

4. Positive Opening Contacts

Emergency stop switches must use positive-opening NC contacts in accordance with EN 60947-5-1. This ensures reliable disconnection even in case of contact welding.

5. Integration into the Overall Safety System

• Must override all other machine functions
• Must remain operational at all times
• Must be installed at each operator station where hazards exist

EN ISO 13850 vs EN 60947-5-5

Emergency Stop Compliance for CE Marking in Germany

In the German machinery market, emergency stop compliance is closely examined during CE conformity assessment. Engineers typically evaluate:

• EN ISO 13850 design compliance
• EN 60947-5-5 conformity
• Positive-opening NC contacts
• 22mm mounting compatibility
• Technical documentation availability

22mm mounting diameter is the most common industrial control panel standard in Germany.

 

Stop Categories According to IEC 60204-1

• Category 0: Immediate removal of power
• Category 1: Controlled stop followed by power removal
• Category 2: Controlled stop without power removal

Emergency stop functions typically implement Category 0 or Category 1, but never Category 2.

Common EN ISO 13850 Compliance Mistakes

• Using non-latching push buttons as emergency stops
• Omitting the yellow background plate
• Allowing automatic restart after reset
• Using contacts without positive opening mechanism
• Treating emergency stop as primary safeguarding

Technical Characteristics of a CE Compliant Emergency Stop Switch

• 22mm standard mounting diameter
• Red mushroom actuator with yellow background
• Twist-to-release mechanism
• Positive-opening NC contacts
• IP65 / IP67 / IP69K options
• CE Declaration of Conformity

FAQ – EN ISO 13850 Emergency Stop Compliance

Is EN ISO 13850 a product certification?

No. It defines design principles for the emergency stop function, not individual product certification.

Can resetting the emergency stop automatically restart the machine?

No. Resetting must not initiate machine restart.

Are positive-opening contacts mandatory for emergency stop switches?

Yes. Emergency stop devices must use positive-opening normally closed (NC) contacts in accordance with EN 60947-5-1 to ensure reliable disconnection, even in the event of contact welding.

Is 22mm the standard emergency stop size in Germany?

Yes. 22mm mounting diameter is the most widely used industrial standard in German control panels.

Conclusion

Complying with EN ISO 13850 requires more than selecting a red push button. It involves functional safety design, electrical reliability, and system-level integration aligned with CE marking requirements.