Air Circuit Breakers (ACB)


We are introducing new ACB generation with the solutions from 800A to 6300A  to suit any application. The ultimate in compactness and operational capability.

The TemPower 2 ACB is extremely reliable in service. All models have a short-time withstand rating equal to the service breaking capacity. This guarantees discrimination, or selectivity, without further calculation because it allows short-circuit protection to be time-delayed, even at the maximum prospective short-circuit current.

Breaking Contacts

TemPower2 is the world’s first DoubleBreak ACB, having two breaking contacts per phase. The unique pole structure means that the short-time withstand rating (Icw) is equal to the service short-circuit breaking capacity (Ics) for all models.

Packing Density

You can increase switchboard packing density using the smallest one-second rated ACB on the market. The fixed version is 290mm deep, the drawout version is 345mm deep.


DoubleBreak contacts increase service life. Electrical and mechanical endurance ratings are the best available, and exceed the requirements of IEC 60 947-2.

Double Quick Opening

TemPower2 ACBs clear short-circuit faults in less than 30ms. That’s twice as fast as most ACBs.

Zone Interlocking

During a fault; considerable thermal and mechanical stresses are placed on the entire system. With the TemPower2 Z Interlock system, the breaker nearest the fault will trip first, irrespective of the short time delay setting.

Protection Characteristics

TemPower2 is the only ACB which offers time-current characteristics to 3 different standards:

  • IEC 60 947-2 (low voltage circuit breakers)
  • IEC 60 255-3 (electrical relays)
  • Lloyds Register of Shipping (for marine generator protection)

All models have LSI protection.

Double Neutrals

How do you make a system harmonic proof in the face of increasing triple-N harmonic currents? Terasaki have launched the first Double Neutral ACB. The AH-60DN will carry 10,000A of neutral current.

ReduceTime to Repair

Modular construction means that each pole of the TemPower2 ACB can be replaced in about 15 minutes – by the user. This unique feature will reduce downtime for end-users.

Control and Monitoring Options

Circuit breaker control and monitoring can be implemented either by hard wiring or digital data transmission. The TemPower2 ACB can support Modbus communication protocol.

NEW AR440SB and AR6 ACBs

Terasaki are committed to the progressive innovation of the TemPower 2 AR ACB. With this in mind we are introducing our new AR440SB 4000A ACB which is based on the AR3 frame size, and new AR6 - 5000A and 6300A ACBs. Our new ACBs come with the same excellent performance expected from all Terasaki products; delivering innovative circuit protection with built in reliability and safety. The introduction of these ACBs provide a solution from 800A to 6300A with the same front cover dimension and standardised accessories.

Double Ground Fault Protection

Restricted and Unrestricted Ground Fault Protection. The AGR-B Protection Relay offers Ground Fault Protection on the line/transformer side (Restricted) and load side (Unrestricted) of the ACB.

How to INCREASE the lifetime of an electrical installation...


These features offer practical methods of increasing reliability in mission-critical installations like:

  • data centres
  • financial centres
  • UPS circuits
  • large sites
  • industrial hospitals

Guide to ACB selection


Guide to selection of protection relays





Contact Us:

Moscow, Russia
Stroitel'nyy proyezd 7А, corpus 7, office 10
Phone/fax: +7 (495) 492-00-97



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