MSHA has been made aware of a hazardous condition that may exist in 600 volt and 1000 volt circuit breakers.
This includes all frame sizes. The circuit breakers may appear to be new or rebuilt, but they have been changed from the manufacturer’s original design. These mining circuit breakers, originally manufactured by Eaton Cutler-Hammer, may have been purchased either directly from the 3rd party or through a mining supply company. There is evidence that some of these circuit breakers have been modified by a 3rd party rebuilder with knock-off 600 volt and 1000 volt covers. The covers are of unknown construction and were not manufactured by Eaton. The labeling affixed to the breakers was also reproduced by the 3rd party rebuilder in an effort to make the circuit breakers look new and legitimate.
Because these covers do not meet manufacturer specifications, it is possible that they will not contain an event within any of these circuit breakers, such as phase to phase or grounded phase. In addition, the frames that the 1000 volt covers were assembled onto may only be rated at 600 volts. Also, the frames used for both 600 volt and 1000 volt have been rebuilt and may contain parts, such as tips and springs, of unknown origin and specifications. Because of the potential for injury and/or death from the failure one of these circuit breakers can cause, they should be removed from service immediately.
The simplest way to determine if you have one of these circuit breakers installed or in your supply house is to run your finger nail down the square portion of the cover where the circuit breaker handle is installed (See illustration below). If the cover is very smooth in this area, you probably have one of the hazardous circuit breakers. If the circuit breaker is in use, it must be removed from service immediately. After the breaker has been removed or if a breaker is found in supply, contact Mr. Tom Grace of Eaton/Cutler-Hammer at 412-418-2169 for further instructions on how to dispose of the breaker. You may also contact Mr. Grace by email at [email protected].
