277/480 Arc Flash

Status
Not open for further replies.
Z

zapped 1

Member
Location
north port fl
These pics are from a 1200 amp, 277/480 switch gear with single-phase 600 and 500 amp I-line breakers feeding boat marina; Engineer says that main breaker failure is reason for explosion. Anyone ever seen anything like this or have any feedback to offer?
 

Attachments

  • IMG_20120430_195149.jpg
    IMG_20120430_195149.jpg
    140.6 KB · Views: 0
  • IMG_20120430_183412.jpg
    IMG_20120430_183412.jpg
    141.7 KB · Views: 0
  • IMG_20120430_194839.jpg
    IMG_20120430_194839.jpg
    141.7 KB · Views: 0
  • IMG_20120430_195128.jpg
    IMG_20120430_195128.jpg
    134.6 KB · Views: 0
i agree but hard to prove now breakers are 6 yrs old poco said no problem with x former marina up and running off temp x former while we wait on new gear to arrive
 
Looks like corrosion of the buss leading to a flashover, what is the system voltage? Being in Florida, I don't know if your on the coast or inland, but salt is your enemy when it comes to electrical parts.
 
Just re-read your post, you did say it was 277/480, I would say with pretty good certainty that it was a flashover. Are there any conduits comming in at the top? Or evidence the door was left open for a period of time? (Assuming this is a 3R enclosure located outdoors)
 
zapped 1 said:
i agree but hard to prove now breakers are 6 yrs old poco said no problem with x former marina up and running off temp x former while we wait on new gear to arrive
Click to expand...

Why would the assumption made that something was wrong with the XF? Just out of curiosity, what stopped the arc, fuse on high side of POCO XF?
 
fuses were blown at poco x former, no damage visible at downstream gear speculation only that maybe poco had fault. a poco engineer has checked x former no fault on them
 
fuses were blown at poco ,no visible damage at downstream x former, speculation only that poco may of had fault engineer has cleared poco x former different engineer outsourced by marina owners says main breaker went bad , but no real reason why yet
 
Hard to say if that is a main breaker failure or just a poor protection system design. I do alot of forensic studies for arc flash and there is a lot of missing info to find the cause but "main breaker failure" is a pretty lame reason, what is he basing that on?
 
Is the connection on the line side of the breakers fingers gripping a bus? If so we have had the connections fail and arc, enough to make the bus at that location and the breaker unusable. Nothing as spectacular as the failure you picture.
 
Status
Not open for further replies.
Top