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Re: 4000A 480V Duct #124487 10/15/06 08:59 AM
Joined: May 2001
Posts: 717
G
George Corron Offline
Member
I once had to help the Fire Dept remove 2 bodies of my friends so I could piece together the Pringle and restore power. If you have Pringle switches please treat them carefully. BTW VAelec this was about 20-25 years ago on K street in DC, can't be too far from your "ooops".

I notice this was AL duct?

I've had to repair way too many buss duct messes in my years, and as often as not, it was a factory connection, not a field joint.

Nowadays it only gets designed in IF there is NO other way, and there usually is.

Glad to hear there were no personnel injuries.

Tools for Electricians:
Re: 4000A 480V Duct #124488 10/16/06 11:33 PM
Joined: Jul 2005
Posts: 49
V
VAElec Offline
Member
I have tried to find a few more answers to how this happened but have not found much. I did hear that the tap section at the top of the riser had some "field engineering" modifications. I don't know exactly what was modified but I would assume it didn't help.

George, oddly enough this seems to be the opposite of what you have seen, it was field modification that seems to have failed. Now I don't want to say that it was the actual modification that was the cause of this failure, especially because numerous factory 90's blew out, but the field mod did not stand up to the fault. And yes to a few things you asked. This is an aluminum bus and also pretty close to K street. The building is on N. Fairfax Dr. in Ballston.

mxslick, I truly do not know the cause of the fault. I do know that the final line in protection for the building opened and it was closed without troubleshooting the fault. What has been said is that water caused the fault but I don't know. Seems like a huge fault to blame on water alone.

Pete


Pete
Re: 4000A 480V Duct #124489 10/17/06 03:59 PM
Joined: Mar 2004
Posts: 391
B
BigJohn Offline
Member
Quote
...the final line in protection for the building opened and it was closed without troubleshooting the fault.
That sounds like pure genuis right there.

-John

Re: 4000A 480V Duct #124490 11/03/06 04:19 PM
Joined: Jul 2002
Posts: 8,379
Trumpy Offline
Member
That hasn't been happy at all.
One thing that never fails to amaze me, is the huge electro-mechanical forces involved with any fault in large current installations.
I've seen busbars that you would think were pretty solid, twisted like they were tin foil.

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