Please help identify this wiring system

[MBeach]

First post here, lurked for a while. I would appreciate any help you guys can give.

Yesterday I was asked to look at a couple of old industrial buildings that had been partially vandalized with wiring removed. I am tasked with determining whether the existing wiring is usable. If not, the owners would like to remove the wiring and scrap the wire. For the life of me, I have never seen a system like this, so I don't know where to begin to research on whether it may be usable or not.

The buildings were built around 1900-1920. When originally built, they were home to a railcar manufacturer. The buildings range from 1000-2500 feet long by 100-200 feet wide.

The wiring in question comes directly from the transformer, up the wall, and enters the building above the bottom of the ceiling joists. In some spots, there are up to 21 what appears to be 250 MCM wires running perpendicular to the length of the building. These wires are supported in groups of 3 by porcelain disc insulators. At various intervals, these wires tap groups of 3 500 mcm wires that run the length of the building. At each end of the run, there is a tensioning mechanism that pulls the wire tight. These wires also are supported by porcelain insulators. The wire itself appears to be insulated via a woven fabric over a rubber type insulation.

It appears that wherever power was needed throughout the building, taps were made on the 500s using either split bolts or soldering, and the wire ran into a pipe down the wall to the various switchgear, which usually consisted of a fusable disconnect. From there, it branched off like any other older style electrical installation.

In my opinion, this appears to be some sort of knob and tube configuration, but I honestly am not sure. I have never come across anything like this, which is why I am humbly asking the opinion of this board.

One building has not been touched by thieves, the wiring is completely intact. Another has had portions cut out. Would it be possible to repair the wiring that has been disturbed? Would it be possible to repower the building that has not been touched without problem? Is this systems still acceptable under the current NEC?

Thanks, and I appreciate any help you could provide.

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[Dennis Alwon]

Looks like Knob & Tube wiring. Where are the breaker boxes? IMO this system needs to go.

 

[fmtjfw]

--or--

--or--

Try 398 Open Wiring on Insulators.

 

[MBeach]

Looks like Knob & Tube wiring. Where are the breaker boxes? IMO this system needs to go.

I had been leaning towards a knob and tube system as well, but this is the first time I have ever run across it in an industrial 3 phase environment. It is really neat.

There are no breaker panels I have found, unless there is some sort of breaker type system in the transformer itself. I wasn't able to inspect any of the transformers yesterday. I plan on going back out there this morning.

At various places where machinery used to be, they just tapped the 500s, and ran it down the wall to a disconnect.

 

[MBeach]

Sorry, Posted pics twice. Please delete

 

[fmtjfw]

From your pictures

From your pictures

It is 398

 

[augie47]

fmtjfw nailed in. Art 398. Still a legal wiring method in specified locations and very common in this area in large indutrail facilities. 240.21(B)(4) if often used in conjunction with this method.

 

[GoldDigger]

fmtjfw nailed in. Art 398. Still a legal wiring method in specified locations and very common in this area in large indutrail facilities. 240.21(B)(4) if often used in conjunction with this method.

So for purposes of detailed analysis, is this a "mill type" building?

 

[MBeach]

So for purposes of detailed analysis, is this a "mill type" building?

Yes, but I have to admit I had to look up the definition of "mill type" building before I could answer.

 

[augie47]

Yes, but I have to admit I had to look up the definition of "mill type" building before I could answer.

That's kinda funny coming from a Birmingham resident..... as an outsider, when I think Birmingham, I think of mills.
Of course, the closest major City to my area was also known for foundries and textile mills most all of which are gone now but there was a time when I often worked with Art 398 wiring... seldom had a short, but when you did it was pretty easy to find

 

[MBeach]

That's kinda funny coming from a Birmingham resident..... as an outsider, when I think Birmingham, I think of mills.
Of course, the closest major City to my area was also known for foundries and textile mills most all of which are gone now but there was a time when I often worked with Art 398 wiring... seldom had a short, but when you did it was pretty easy to find

I am a recent transplant from Kentucky. I have only been here a couple of years. I live outside of Birmingham, and to be honest know very little to nothing about the city itself. I only recently have been hearing about the old steel mills, textile mills and the like.

I had never been inside any industrial building near this age, much less in Alabama.

 

[don_resqcapt19]

In some old plants around here, the tap was made by wraping a #12 around a roofing nail and driving that into the 500 kcmil. The 12s would drop down to a disconnect below.

 

[augie47]

In some old plants around here, the tap was made by wraping a #12 around a roofing nail and driving that into the 500 kcmil. The 12s would drop down to a disconnect below.

Early fault-current protection a high surge could blow the nail free

 

[USMC1302]

Don:
Quite a few locals tried what you described to tap power when I was in Iraq, didn't work out too well for them...