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1 members (Scott35),
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Joined: Feb 2005
Posts: 219
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Thanks Bob.
The pic does not show whats being fed.
Rob
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Joined: Feb 2003
Posts: 288
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Quote: "How many beginners would get to make decisions about this size installation anyway?"
It's not necessarily the beginners I'm worried about. I've had countless guys with 20+ years experience insist that there was nothing wrong with separating phases in parallel conduits. They had never heard of inductive heating.
The young ones aren't so bad. Set 'em straight once, and they believe you, especially if you make them find it in the book. If nobody sets them straight, 10 years later they're sure they know everything.
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Joined: Jun 2004
Posts: 206
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I took the picture during an Infrared inspection of the electrical distribution equipment for a small manufacturing facility. It is a 2500 amp 480/277 service. It was installed 25 years ago. The picture shows the point of entrance from the utility transformer to the CT cabinet. The service is hot sequence metering. The lugs shown are the line side of the CT's. The 1 1/4" PVC carries the wires between the CT's & the remote utility meter. The small conductor zip tied on the left was for the neutral connection for GFP of the main disconnect.
Al
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Joined: Feb 2005
Posts: 219
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thanks Al
That explains the lack of visible grounding in this section.
Rob
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Joined: Feb 2003
Posts: 288
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Hot sequence metering? I guess I don't know what that is.
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Joined: Jun 2003
Posts: 681
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How about 230.8, this is one item that I see missing in a lot of installations. Don't forget 300.5(G) and 300.7(A).
With that installation being installed 25 years ago, I can see the size of the neutral conductor, but with todays concerns for neutral capacity, I doubt you will see neutrals that size.
BTW - for a 25 year old installation, it looks to be in very fine shape. That is why Capt Al's infrared inspection is so important.
Pierre Belarge
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Joined: Jun 2004
Posts: 206
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Yaktx, basically hot sequence metering: The current transformers for the utility meter are before the Main disconnect switch. The only way to to service the CT's is for a utility shutdown. Most services in my area have gone to cold sequence metering which puts the main disconnect ahead of the CT's.
Al
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Joined: Feb 2003
Posts: 288
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OK, I get it. Hot sequence, that's the way it's done around here. However, I know of one municipality nearby where even two-family dwellings have a main disco ahead of the metering.
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Posts: 57
Joined: August 2003
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