Not a storage space!

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tread

tread

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I was called to a ice arena for a disconnect problem. This is what I found. A 600 amp 600v rated switch, with 600 amp fuses had experienced an arc flash. The source is unknown, but I can tell you I megged everything and found no problems. This switch runs refrigeration compressors mounted on a skid. The skid has overcurrent protection via fused disconnect, with 300 amp fuses. All 600A fuses were open and no other fuses were failed. Looks like there was an arc drawn to the cover or chassis of the 600 amp switch. The switch has been sent to Square "D" for analysis. A new switch was installed and no further issues were found. The burnt up stuff in front of the panel was a box with pvc plumbing fittings. Good thing it wasn't a larger box.
http://forums.mikeholt.com/attachme...ment.php?attachmentid=2883&stc=1&d=1235236196
 
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KentAT

Senior Member
Location
Northeastern PA
Boy, if someone was walking from right to left, carrying a box of PVC fittings, accidentally hooked the switch handle that is in the "ON" position while lots of amps were flowing, would that explain it?

(Look for the white-as-a-ghost employee who went home sick that day...)

kent
 
tread

tread

Member
The load was about 50 amps, there was only 1 compressor running. The only person in the building at the time was the clerk in the office.The power went out and came back on in the building. She then went to restart the refrigeration equipment and discovered the problem. The power went out all over town,( small town, pop.2000) and then came back on in less than a minute. The power co. verified the outage. The main was not tripped in this building and no other problems were found.
 
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charlietuna

Senior Member
Could you explain what the second photo shows?? How did that material get out of the switch and onto the floor??? The enclosure is supposed to contain the explosion or burnt materials. I agree, someone didn't fully explain what caused this problem ?? The cover of the disconnect must have been open when the fault accurred!
 
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