Outdoor 480V Buss Duct

[wanderer20001us]

Looking for opinions.

I have always been against installing buss duct in outdoor application. I have a site that has had two seperate failures on the same 2500A buss duct on an existing system. The buss is served by a outdoor 2500A BPS w/ GFR, runs up the outside wall of the buidling, across the roof, and down into the electrical room. I am proposing a complete redo of the 2500A feed inside the building as the solution. This feeds 'critical' Data Center infrastructure and should have never been installed as it was (IMHO).

This is not the first time I have been involved with the failure of outdoor buss duct. I've seen failures on just about ever buss duct manufucturer out there in outdoor applications.

What is the experience of others? Am I just lucky to have seen these failures or am I correct in my assesment of this practice as unreliabile and prone to failure? Could these be installation problems (Note: The failures in my present situation occured in the middle of 10' sections)? This is in Michigan so it would be nice to hear from others around the country.

 

[steve66]

Re: Outdoor 480V Buss Duct

The only outdoor bus duct I have seen also failed. It was a 2000A 208V duct to a school that also ran down an exterior wall.

We were getting ready to remodel a school, and I took a look at it since it was the first outdoor bus duct I had seen up close. It didn't really seem watertight, and it seemed to have holes in the bottom of it. I wondered if someone could stick their finger in and make contact with one of the buses.

Before the remodel got under way, the bus shorted and started a fire shutting down the school until the duct could be replaced.

By the way, this is in Central Illinois.

Steve

[ July 02, 2004, 03:10 PM: Message edited by: steve66 ]

 

[rbalex]

Re: Outdoor 480V Buss Duct

Non segregated phase outdoor bus duct is a staple for petrochem and many other large campus-style industrial facilities. (Its virtually switchgear without the breakers ) It has a very reliable history. "Sandwich" or isolated-phase style is all but prohibited outdoors. (Google search: "non-segregated bus duct)

You might also look at cable-bus (duct bank in the sky). It also has an excellence service record in the industries I work with. (Google search: "calvert cable-bus")