Circuit breakers have safeguarded users and protected electrical equipment for more than 50 years, but until now, electricians had no reliable way to verify that the devices were safe or would perform as intended by the NEC. Rather than deenergizing and rearranging existing circuitry to provide positive branch-circuit identification, some electricians choose to work on live circuits.
“It might take you 20 minutes to find out which breaker it is and then shut it off,” says Paul Keleher, a Massachusetts electrician. “That's 20 minutes that an electrician can't spare. We work hot by default because we don't have an efficient way to shut down.”
Keleher remembers using a male cord cap connected to a light switch to shut down a line. After 25 years in the electrical industry, he searched for an engineer to help him invent a safer way to trip a circuit. On a service call, he met Chuck O'Neal, an electrical engineer experienced in product development and test instrumentation. Keleher shared his idea about branch-circuit testing while upgrading O'Neal's electrical service, and they agreed to work together on the invention. In 1998, O'Neal and Keleher earned a patent and started developing prototypes and conducting field tests for their products. Five years later, they founded KO Instruments to commercialize their flagship product — the CBA-1000 Circuit Breaker Analyzer.
The device tests the overcurrent response of any 120V/15A or 20A thermal/magnetic circuit breaker. Its microprocessor technology characterizes a circuit and then calculates the correct breaker response and time interval required for proper circuit protection. All breakers are designed to operate within safe limits, but after years of operation in damp environments, they may fail to operate in that period of time. The tester alerts users to a potentially unsafe breaker that could cause a fire. The analyzer predicts the “strength” of the circuit by measuring the circuit's voltage and current capacity. The “stronger” the circuit, the more quickly the circuit breaker needs to operate. The typical test intervals range from 60 msec for a strong circuit to upwards of 6 sec for a weak circuit.
To operate the unit, users plug the trip module into a 120V receptacle outlet, wait a few seconds for the unit to calibrate, and then press a button to qualify the circuit as safe for testing. Pressing the button a second time initiates a precisely timed test. If the breaker trips, it has passed the test, but if the circuit is still live at the conclusion of the test, the breaker has failed. When users press the button a third time, the unit will report why the breaker passed or failed and provide more information about the condition of the circuit.
The analyzer stores test results for maximum safe breaker response time, actual safe breaker response time, breaker performance, actual fault current, and series fault detection. The replaceable plug-and-play trip module is good for 1,000 operations. The product also features reporting capability software that allows users to download test data to a PC and manipulate the data to create reports.
For product specifications, click here.
Visit www.koinstruments.com for more information.