Multi-Amp/Megger CB-832 Circuit Breaker/Overload Relay Test Set

Multi-Amp/Megger CB-832 Circuit Breaker/Overload Relay Test Set
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The Megger CB-832 test set is a high-current circuit breaker and overload relay test set. The CB-832 is designed to test the circuit breaker and overload relays by means of primary current injection. The CB-832 is a self-contained test set that incorporates a variable high-current output and appropriate control circuitry and instrumentation for testing thermal, magnetic or solid-state motor overload relays; molded-case circuit breakers, and ground-fault trip devices.

One of the most common applications of the Megger / Multi-Amp CB-832 is the calibration of magnetic overload relays, such as those used for protecting air conditioning systems. By providing up to 1000 amperes to simulate overload conditions, it also is capable of testing the time-delay characteristic of magnetic overload relays rated up to 500 amperes.

In addition, the Megger / Multi-Amp CB-832 can test the time-delay characteristics of thermal motor overload relays and molded-case circuit breakers rated up to 225 amperes,when following the recommended test procedure of testing the time delay of thermal devices at three times their rating.

Higher currents are available for the short durations required to test an instantaneous trip element. For example, the test set will provide a short-duration output of 1800 amperes through a typical 225 ampere, molded case circuit breaker. Additional applications include verifying the ratio of current transformers.


  • Digital memory ammeter
  • Digital, multirange timer
  • High-current output
  • Solid-state output initiate circuit
  • Overload and short-circuit protection


(specify one)
120 V OR 240 V, 50/60 Hz, 1Ø
Output Output Ranges (Continuously adjustable in three ranges to meet a variety of test circuit impedances):
0 to 500 A at 3.5 V max.
0 to 125 A at 14 V max.
0 to 25 A at 70 V max.
Output Capacity The output circuit is designed to provide short duration overloads. The output ranges will provide several times their 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 magnetic overload relays rated to 500 A using a test current of two times their rating (1000 A)
Overload Capability
Percent Rated Current Maximum Time On MaximumTime Off
100 (1x) 30 min 30 min
200 (2x) 3 min 8 min
300 (3x) 30 s 4 min
400 (4x) 7 s 2 min
It will test the time-delay characteristic of thermal devices rated up to 225 A using the recommended test current of three times their rating (675 A).Also, to perform an instantaneous trip test, it will provide 1800 Athrough a typical 225-ampere, molded-case circuit breaker
Overload Capability</td> To increase use of the test set, it is designed so that the current ratings may be exceeded for short durations. Because the magnitude of the output current is determined by the impedance of the load circuit, the voltage rating must be sufficient to push the desired current through the device under test and the connecting test leads
Initiate Circuit
The test set uses a solid-state output initiating circuit. To increase reliability and eliminate contact maintenance, this circuit uses a triac instead of a contactor to initiate the output
Output Initiate
Control Circuit
The initiating control circuitprovides momentary and maintained modes to control outputduration.The momentary mode is used whenever the output is to be for a short duration. An example is an instantaneous trip test, or toavoid damage or overheating of the device under test while setting the test current.In the maintained mode, the output remains energized until manually turned off or, when performing timing tests, until the device under test operates this both stops the timer and deenergizes the output