Door-coupling rotary operating mechanism  according to IEC standards.

Control Panel Tips

Control panels in the international market are subject to requirements for protection against direct contact and electric shock according to IEC 61439-1/2 (Low-voltage switchgear and controlgear assemblies) and IEC 60204-1 (Safety of machinery). To comply with these requirements, it must be ensured that live parts cannot be touched under normal operating conditions.


The IEC standards specify that enclosure doors must be interlocked according to certain specifications but at the same time allow maintenance and service work by skilled electricians.

Tips for you!

The door-coupling rotary operating mechanism is designed for installation in control panels and distribution boards. The mechanism basically consists of a handle, a front-operated rotary mechanism with shaft butt having an extension shaft and coupling piece if necessary. Installation on both the front or side is possible. (see picture above)

Accessories for door interlocking according to IEC 60204-1

With more than 500 accessory components, the 3VA molded case circuit breakers and disconnects can be configured as needed in order to add additional functions and adapt flexibly to specific requirements. 

A control panel can be designed without door interlocking under the following conditions:

  • Operating voltage ≤50 V AC or ≤120 V DC according to IEC 60364-4-41 (SELV/ Safety Extra Low Voltage and PELV/ Protective Extra Low Voltage)
  • It has no door (e.g. only a cover without hinges, which can only be removed with a tool) 

Yes. According to IEC 60204-1 and IEC 61439-1, a twist lever is permissible as door interlock of a control panel.


However, it must be guaranteed here that only skilled electricians or instructed persons can gain access. Otherwise, access is possible with the aid of a key (e.g. including triangular socket, square socket, double-bit) or a suitable tool.

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