Arc Flash Study - FPE Breakers

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I am doing an arc flash study on a facility that has an old switchgear unit from the 1970s with Federal Pacific Electric breakers. Since the company is out of business, is there any hope of me finding the Time Current Curves for these breakers? And if not, is it acceptable for me to just plug in a similar type Molded Case Circuit breaker into my model for the calculations?
 

chris kennedy

Senior Member
Location
Miami Fla.
Occupation
60 yr old tool twisting electrician
Thats an interesting question.

FPEWarning.jpg
 

GearMan

Member
Location
WI
Chris, great response, you made my day. I was a Westinghouse rep. at that time when FPE handed out the warning labels. Quite the stir in the industry. I still have one in my desk drawer.
 

zog

Senior Member
Location
Charlotte, NC
I am doing an arc flash study on a facility that has an old switchgear unit from the 1970s with Federal Pacific Electric breakers. Since the company is out of business, is there any hope of me finding the Time Current Curves for these breakers? And if not, is it acceptable for me to just plug in a similar type Molded Case Circuit breaker into my model for the calculations?

Which is it, switchgear or molded case breakers? I should have the curves, for any FPE breakers you would find in switchgear, and some MCCB ones.

What software are you using?
 
Wow, if you really have these curves, you would be a life saver.

I believe the breakers are molded case breakers. I have frame numbers: NN, HFJ, HEF, HJL, NFJ & NEF.

I was able to find to find the submittal from IEM for the switchgear and all the distribution panelboards they provided back in 1974 and it has all the breaker catalog numbers in there. So, that helped a lot, but yea if you have the curves please let me know and I can PM you to get them.

I am using SKM, but I also have EasyPower if need be.

Thanks!
 

charlie b

Moderator
Staff member
Location
Lockport, IL
Occupation
Retired Electrical Engineer
I hesitate to bring this up, but wouldn't an arc flash study be a wasted effort? If I correctly remember this brand of panel having a reputation for failures, then knowing what the curves say about trip times may have nothing to do with the reality of when, if ever, they would trip in a real fault situation. Any kind of failure, or even a short delay in tripping, would significantly alter the amount of arc flash energy that could be released. Therefore, any information posted on the board, with regard to PPE requirements, would be, at best, a guess. As a professional engineer, I would not want to sign off on a study that involved unreliable equipment.
 

zog

Senior Member
Location
Charlotte, NC
I hesitate to bring this up, but wouldn't an arc flash study be a wasted effort? If I correctly remember this brand of panel having a reputation for failures, then knowing what the curves say about trip times may have nothing to do with the reality of when, if ever, they would trip in a real fault situation. Any kind of failure, or even a short delay in tripping, would significantly alter the amount of arc flash energy that could be released. Therefore, any information posted on the board, with regard to PPE requirements, would be, at best, a guess. As a professional engineer, I would not want to sign off on a study that involved unreliable equipment.

That is true for any arc flash study, which is why the 70E added the requirements to test OCPD's. These breakers have about the same failure rates as anything else out there the same age. (I think you are refering to stab-lok breakers, they had issues)
 

ATSman

ATSman
Location
San Francisco Bay Area
Occupation
Electrical Engineer/ Electrical Testing & Controls
FPE Legacy

FPE Legacy

I hesitate to bring this up, but wouldn't an arc flash study be a wasted effort? If I correctly remember this brand of panel having a reputation for failures, then knowing what the curves say about trip times may have nothing to do with the reality of when, if ever, they would trip in a real fault situation. Any kind of failure, or even a short delay in tripping, would significantly alter the amount of arc flash energy that could be released. Therefore, any information posted on the board, with regard to PPE requirements, would be, at best, a guess. As a professional engineer, I would not want to sign off on a study that involved unreliable equipment.

I agree with you 100%. Reminds me of the time when I was a junior field service engr for Westinghouse in the late 70's. I was racking out a 4000A LV FPE main breaker from a double-ended sub with the line side energized (2500KVA xfmr.) FPE sold a LOT of equipment to governmental agencies back then because of their LOW BID policy. Back then no one ever heard of PPE. As I was struggling to rack the breaker out we heard a loud KLUNK! We all looked at each other puzzled, but I had to continue the racking. With the breaker out of the cell we found that the phase B line side round pole piece fell off the back of the breaker; broken weld. Had this big 24" long "thick copper pipe" gone phase to phase on the line side you would not be reading about this story :eek:
Charlie, can you tell us the available short circuit fault current at the line side with
a percent impedance of 5% ?
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
Charlie, can you tell us the available short circuit fault current at the line side with
a percent impedance of 5% ?

no one can tell you what it really is. you can calculate it based on an infinite bus but that is the maximum and in the real world the actual SCC will likely be a lot less.
 
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