Multi-Amp/Megger CB-845 Circuit Breaker Test Set

Multi-Amp/Megger CB-845 Circuit Breaker Test Set
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Multi-Amp CB-845
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The Model CB-845 test set is a high-current circuit breaker test set consisting of a control unit that incorporates the latest in solid-state metering, control technology and a high-current output unit. The lightweight, two-section design of Model CB-845 enables the user to easily transport the unit into areas previously inaccessible to high-current test equipment such as elevated or subsurface load centers, shipboard power panels, elevator machinery rooms and other isolated locations.


  • Digital memory ammeter: High-accuracy, directreading instrument features read-and-hold memory for
  • measurement of short-duration currents.
  • Digital, multirange timer: Crystal controlled, highaccuracy instrument measures operating time to 1 ms.
  • Lightweight and portable: Two-section unit has a total weight of only 175 lb (80 kg).
  • High output current: Provides instantaneous current up to 5000 amperes through a 500 ampere circuit breaker.
  • Solid-state output initiate circuitry: Solid-state output circuit switching eliminates need for contact maintenance.
  • Protection: Overload and short- circuit protection is incorporated.
  • Enclosure: The test set is housed in two stackable, interlocking, rugged, metal enclosures with convenient carrying handles. The control unit comes with a lid for protection of the controls during transportation. The unit is easily transported by and/or on a standard hand truck.


Model CB-845 is suitable for a wide variety of testing requirements including molded-case circuit breakers; thermal, magnetic or solid-state motor overload relays and other overcurrent protective devices. Additional applications include verifying the ratio of current transformers and testing ground-fault trip devices. The time-delay characteristics of motor overload relays and molded-case circuit breakers rated up to 500 amperes can be tested with Model CB-845, when following the recommended test procedure of testing the time delay of thermal devices at three times their rating.  Instantaneous trip elements can be tested with the higher currents required for these tests. For example, the test set will provide short-duration output of 5000 amperes through a typical 500 ampere, molded-case circuit breaker.


Voltage (switch-selected) 208 and 240 V, 1φ, 30 A
Input Frequency (specify one) 50 Hz OR 60 Hz
Output Range: the output is continuously adjustable to accommodate a variety of test circuit impedances: 0 to 1200 A at 6 V max.

Output Capacity: the output circuit is designed to provide short-duration overloads. The above output range will provide several times its current rating, provided the output voltage is sufficient to push the desired current through the impedance of the test circuit. The test set is capable of testing the time-delay characteristics of devices rated up to 500 A using a test current of three times their rating (1500 A). Additionally, to perform an instantaneous trip test, it will provide 5000 A through a typical 500 A, molded-case circuit breaker connected with the 4 ft (1.2 m) test-leads provided.