megloff11x
Senior Member
For a motor short circuit and ground fault protection, what listings and ratings must a circuit breaker have?
We have UL489 for Branch Circuit protection and UL1077 for Supplemental protection. Recent articles have noted that UL1077 doesn't meet the requirements for motor protection unless the motor is in a machine that has been sent through the UL or similar testing & listing process. Why would UL or CE stamp such a device containing 1077 devices unless they overlooked it, or unless they passed the various tests in spite of themselves? There is also some leeway if a UL489 device is upstream, but different sides claim different things.
Many articles also note that the UL1077 devices look just like other breakers and are often called miniature circuit breakers or similar.
There is also some confusion on whether a 480/277V rate breaker is good enough for 480V. And many breakers are stamped for up to 480V use. Then we have a complexity of other ratings, where UL only says it's good to this, but the manufacurer gives you a whole bunch of special conditions that UL didn't stamp as part of their standard tests, or are certified by IEC or others, and with a wink and a nod, off you go. If you don't pour over the fine print, you might think that UL certified their "By the way" specifications too.
It would be nice if the people who made the equipment used the same ratings and terminology as the NEC, and spelled this out in their literature. It might cost them a few sales, but it also might save them a lawsuit.
Is there any good guide book or article out there that spells this all out, AND NAMES NAMES? I'd like to see a chart with manufacturer, breaker/supplemental protector model number, can it be used for (application list), what do its ratings REALLY mean (which are certified by a NRTL and which are their non-NRTL certified claims).
It would be hard for NEC to cite UL standards because UL could get a wild hair and change its numbering systme, thus changing NEC's specifications without their knowledge. This is why the military used to specify WD-numbered steels. WD8620 is the same as SAE8620, but if SAE changed its recipe, the WD8620 stayed the same. End of aside.
But back to my real question: I'm looking for a circuit breaker for protection of a 480V 3-phase servo motor & controller that draws 40A Full load current rating. Can anyone suggest a manufacturer & model that meets code and UL?
Matt
We have UL489 for Branch Circuit protection and UL1077 for Supplemental protection. Recent articles have noted that UL1077 doesn't meet the requirements for motor protection unless the motor is in a machine that has been sent through the UL or similar testing & listing process. Why would UL or CE stamp such a device containing 1077 devices unless they overlooked it, or unless they passed the various tests in spite of themselves? There is also some leeway if a UL489 device is upstream, but different sides claim different things.
Many articles also note that the UL1077 devices look just like other breakers and are often called miniature circuit breakers or similar.
There is also some confusion on whether a 480/277V rate breaker is good enough for 480V. And many breakers are stamped for up to 480V use. Then we have a complexity of other ratings, where UL only says it's good to this, but the manufacurer gives you a whole bunch of special conditions that UL didn't stamp as part of their standard tests, or are certified by IEC or others, and with a wink and a nod, off you go. If you don't pour over the fine print, you might think that UL certified their "By the way" specifications too.
It would be nice if the people who made the equipment used the same ratings and terminology as the NEC, and spelled this out in their literature. It might cost them a few sales, but it also might save them a lawsuit.
Is there any good guide book or article out there that spells this all out, AND NAMES NAMES? I'd like to see a chart with manufacturer, breaker/supplemental protector model number, can it be used for (application list), what do its ratings REALLY mean (which are certified by a NRTL and which are their non-NRTL certified claims).
It would be hard for NEC to cite UL standards because UL could get a wild hair and change its numbering systme, thus changing NEC's specifications without their knowledge. This is why the military used to specify WD-numbered steels. WD8620 is the same as SAE8620, but if SAE changed its recipe, the WD8620 stayed the same. End of aside.
But back to my real question: I'm looking for a circuit breaker for protection of a 480V 3-phase servo motor & controller that draws 40A Full load current rating. Can anyone suggest a manufacturer & model that meets code and UL?
Matt