Limitations of electrical enclosures

Lost_RFTech

Member
Location
IL., Ia., Mo.
That is a good article and I like that they address the issue of resetting circuit breakers without performing adequate tests to insure that you are not closing in to a fault.

I work in a large and aged facility (>>4000 motors up to 1500HP, some 1957 vintage switch gear) that has been poorly designed, maintained, and up until recently, operated with a policy that stated that a single reset of a tripped OCPD was acceptable - even encouraged - without first doing any sort of fault analysis.
Little or no consideration is given to the concern of things like a welded starter contact that would remove 1/2 of the fault handling capability of a series rated bucket, etc...

I like that this article is found on the web site of a safety organization rather than a regulatory agency or a PPE manufacturer, hopefully it would carry a bit more weight with the safety folks around here who are largely ignorant of any electrical safety concerns based on common sense and sound engineering practice.

I'm new to this industrial electricity world, having spent the first 30-ish years of my working life in the electronics world. I hope I don't step on any toes, but to make a pretty broad generalization here, I see a lot more lax engineering approach both at this facility and with system and equipment vendors than I'm used to.
I read this site diligently, one of the biggest reasons why being that I have seen a display of safety and sound engineering practice consciousness that is sorely needed in the industrial world.
 

zog

Senior Member
Location
Charlotte, NC
That is a good article and I like that they address the issue of resetting circuit breakers without performing adequate tests to insure that you are not closing in to a fault.

I work in a large and aged facility (>>4000 motors up to 1500HP, some 1957 vintage switch gear) that has been poorly designed, maintained, and up until recently, operated with a policy that stated that a single reset of a tripped OCPD was acceptable - even encouraged - without first doing any sort of fault analysis.
Little or no consideration is given to the concern of things like a welded starter contact that would remove 1/2 of the fault handling capability of a series rated bucket, etc...
That comes from a commonly ignored OSHA regulation that has been in place for decades.

1910.334 (b)(2) "Reclosing circuits after protective device operation." After a circuit is deenergized by a circuit protective device, the circuit protective device, the circuit may not be manually reenergized until it has been determined that the equipment and circuit can be safely energized. The repetitive manual reclosing of circuit breakers or reenergizing circuits through replaced fuses is prohibited.

Note: When it can be determined from the design of the circuit and the overcurrent devices involved that the automatic operation of a device was caused by an overload rather than a fault condition, no examination of the circuit or connected equipment is needed before the circuit is reenergized.

I like that this article is found on the web site of a safety organization rather than a regulatory agency or a PPE manufacturer, hopefully it would carry a bit more weight with the safety folks around here who are largely ignorant of any electrical safety concerns based on common sense and sound engineering practice.

I'm new to this industrial electricity world, having spent the first 30-ish years of my working life in the electronics world. I hope I don't step on any toes, but to make a pretty broad generalization here, I see a lot more lax engineering approach both at this facility and with system and equipment vendors than I'm used to.
I read this site diligently, one of the biggest reasons why being that I have seen a display of safety and sound engineering practice consciousness that is sorely needed in the industrial world.
That is pretty typical in the industrial world, the problem is IMO that the safety people have little or no technical background and often do not work in harmony with the people in the company that have the technical knowledge and experience for that specific equipment.
 

cornbread

Senior Member
Thanks... I have our next safety meeting topic.... Again, really appreciate you and this forum for sharing informantion;:thumbsup:
 
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