Selective main circuit breakers (SMCBs)

Selective main circuit breakers (SMCBs)

Incomparable performances to meet high demanding customer needs

Selective main circuit breakers (SMCBs) protect electrical installations from short-circuits and overloads. In addition, they offer selectivity to downstream miniature circuit breakers and upstream protective devices thanks to outstanding current-limiting selectivity.

Thanks to the selectivity SMCBs maximize availability, especially in applications like data centers, hospitals, office buildings, etc.

As SMCBs are designed for overvoltage category IV and incorporate isolation function, they are predestinated for the use in any main distribution cabinet or meter board as main protecting and isolating device. ABB SMCBs are line-independent without any connection to an external power supply or to a Neutral conductor.


Main benefits

  • Total selectivity to downstream miniature circuit-breaker
  • Outstanding selectivity to upstream protective devices due to unique current limiting selectivity
  • Can be used as main isolating device


Main features

  • Separate product ranges for DIN rail mounting or direct busbar mounting,
  • Available in all common pole variants (1p, 2p, 3p, 4p) and also as 3pole block with single pole tripping,
  • Tripping characteristics Eselective and Kselective,
  • Compliant to the product standards: VDE 0641-21, IEC/EN 60947-2, GB 24350.
  • The auxilliary contact S750DR-aux with two change-over contacts indicate the contact position of the S750DR pole(s) independently and potential-free.

Product overview


MountingDIN-Rail mountingDIN-Rail mounting
Product standardDIN VDE 0641-21IEC/EN 60947-2
Poles1P, 2P, 3P, 4P, 3 x 1-pole1P, 2P, 3P, 4P
Rated current16…63A16…100A
CharacteristicEselective Kselective

Mounting40 mm busbar system
Product standardDIN VDE 0641-21
Poles1P, 3 x 1-pole
Rated current16…63A


Furthermore ABB offers the auxiliary contact for the S750DR range. S750DR-AUX is a two change-over contact that indicates the contact position of the S750DR pole(s) independently and potential-free. This helps to easily monitor individual circuits.