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Safety Relays

Unlike other relays, safety relays ensure the safety function even if contacts are welded together because they have forcibly guided (linked) contacts (EN 50205).

Note: Welding cannot be pulled apart.

(1) Main Safety Relay Requirements


  • The gap between contacts must be at least 0.5 mm during normal operation or when a fault occurs.
  • Contact load switching must conform to AC-15 and DC-13 (IEC 60947-5-1).
  • The mechanical service life must be at least 10 million operations.


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    If at least one normally open contact is welded, when the coil is de-energized, all normally closed contacts maintain a gap of at least 0.5 mm. Even if a normally closed contact is welded, all normally open contacts maintain a gap of at least 0.5 mm in the coil energized mode (in accordance with EN 50205).


    Relays that use forcibly guided contacts for all of the contacts are called Class A and indicated by the mark.


    (2) Structural Comparison of General Relays and Relays with Forcibly Guided Contacts


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