# Free-Air THHN



## Big John (May 23, 2010)

So, we had a contractor install a feeder. 4 parallel runs of 750MCM. He ended the conduit about 4 feet above the switchgear, at which point the THHN free-airs into the the switchgear. They ran a bonding jumper from the conduit to the gear, and the holes in the gear are bushed.

I think this is a really shoddy installation, but try as I might I can't honestly find a reason it's a violation. 

I originally turned to 300.12 but that says "Metal...raceways...shall be continuous between cabinets, boxes, *fittings*, or other enclosures or outlets."

And the definition of "fitting" seems to include bond bushings. So the conduit is continuous, all the way to the bond bushing on the end, at which point the conductors free-air. 

Thoughts?

-John


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## mattsilkwood (Sep 21, 2008)

Big John said:


> So, we had a contractor install a feeder. 4 parallel runs of 750MCM. He ended the conduit about 4 feet above the switchgear, at which point the THHN free-airs into the the switchgear. They ran a bonding jumper from the conduit to the gear, and the holes in the gear are bushed.
> 
> I think this is a really shoddy installation, but try as I might I can't honestly find a reason it's a violation.
> 
> ...


 I have seen it done that way one time. There was a tray above the gear and the various feeders dropped about two feet into the gear. 
That part didn't bother me too bad but they had the service conductors done the same way. They were piped from the tranny up an outside wall, then through the wall just above the cable tray and free air into the gear. 
I have no idea if it was legal or not, it wasn't part of our work so I never really gave it a second thought.


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## McClary’s Electrical (Feb 21, 2009)

Big John said:


> So, we had a contractor install a feeder. 4 parallel runs of 750MCM. He ended the conduit about 4 feet above the switchgear, at which point the THHN free-airs into the the switchgear. They ran a bonding jumper from the conduit to the gear, and the holes in the gear are bushed.
> 
> I think this is a really shoddy installation, but try as I might I can't honestly find a reason it's a violation.
> 
> ...


 

It's illegal, and that's the key word why. If your analogy was correct, he could stop the pipe after the first coupling. That type wire IS NOT tray cable, so therefore it needs protection


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## jwjrw (Jan 14, 2010)

I've seen installs like that in pictures. I wonder why they did it that way.


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## raider1 (Jan 22, 2007)

I agree with Mcclary's electrical. 300.12 requires the raceway to be continuous from enclosure or box to enclosure or box. Terminating in a connector with a bushing and running free conductors through a bushed hole in the top of the switchgear would not meet the requirements of 300.12.

Chris


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## jwjrw (Jan 14, 2010)

I agree also but I have seen installs like that in pictures. I can think of any reason for this. Crazy if you ask me.


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## Big John (May 23, 2010)

I can guess why they did it: Because their other option would have been to offset the rigid (and they probably didn't have a 4" bender) or else use 4" flex (which they probably didn't have available.) 

The cable-tray version of this, I see all the time. But that's explicitly legal. If I remember correctly, code says 6' of unsupported cable-tray between the tray and the equipment is allowed.

I hate to argue with you guys, because I'd love to make them redo this, but it says "cabinets, boxes, fittings *or* other enclosures or outlets." If the article offers the option of "fitting or other enclosure," and they chose "fitting" instead of "enclosure," how can I seriously stand there and tell them they're wrong?

I don't like it, but I think I need to dig for a different article to throw at them.

-John


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## raider1 (Jan 22, 2007)

If raceways could just end in a connector and not be attached to an enclosure then Exception #2 to 300.12 would not be needed.

Chris


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## McClary’s Electrical (Feb 21, 2009)

raider1 said:


> If raceways could just end in a connector and not be attached to an enclosure then Exception #2 to 300.12 would not be needed.
> 
> Chris


 

I agree, and again, nobody would ever need to run pipe past the first coupling if his ananlogy were correct.

Even if somehow, someone agrees with THAT PART of the installation, you still have to protect the THHN from physical damage, and thirdly

there's still 300.18 (a) to deal with


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## Big John (May 23, 2010)

mcclary's electrical said:


> There's still 300.18 (a) to deal with


To me, 300.18 this is more of the meat-and-potatos. This is what I'm gonna site as a reference. 

It seems like 300.12 just reads that a piece of pipe has to have _something_ on the end of it, be that thing connector or a bushing or a box, and I do think they met the requirements of that one.

I never figured that I'd ever have to look this up to prove it to someone. :wacko:

-John


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## Shorty Circuit (Jun 26, 2010)

Big John said:


> I can guess why they did it: Because their other option would have been to offset the rigid (and they probably didn't have a 4" bender) or else use 4" flex (which they probably didn't have available.)
> 
> The cable-tray version of this, I see all the time. But that's explicitly legal. If I remember correctly, code says 6' of unsupported cable-tray between the tray and the equipment is allowed.
> 
> ...


They could have run those last 4 feet in GF directly into the switchgear or into a box mounted on top of the switchgear. Did the electrical inspector pass it? What do you mean the electrical inspector? What electrical inspector? What permit? What drawings? We don't do things around here that way. We march to the beat of a different drummer!:tank:


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## Big John (May 23, 2010)

Shorty Circuit said:


> They could have run those last 4 feet in GF directly into the switchgear or into a box mounted on top of the switchgear.


Absolutely. And greenfield would have been really easy, I don't know any reason other than laziness that they didn't.


> Did the electrical inspector pass it? What do you mean the electrical inspector? What electrical inspector? What permit? What drawings? We don't do thing around here that way. We march to the beat of a different drummer!


Sounds like you work for a utility, too! :thumbup: We once had an indoor substation shut down to replace a bad 25kV PT. Somehow a city inspector got wind that there was "power off to a building for electrical repairs." He demanded to inspect the job before we re-energized. He walked in all gruff, spoiling for a fight, took one look around at all the OCBs, air-breaks and insulators; his eyes got as big as dinner-plates and he stammer _"I... I think this out of my jurisdiction!"_ I thought I was gonna die laughing. :laughing:

-John


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## Bkessler (Feb 14, 2007)

There wasn't enough room for a 90 and he could afford lb's. Seems like you should have a top hat made or installed.


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## goose134 (Nov 12, 2007)

Bkessler said:


> There wasn't enough room for a 90 and he could afford lb's. Seems like you should have a top hat made or installed.


Agreed. The only time I've seen free air conductors out of switch gear is for temps.


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## Shorty Circuit (Jun 26, 2010)

Big John said:


> Absolutely. And greenfield would have been really easy, I don't know any reason other than laziness that they didn't. Sounds like you work for a utility, too! :thumbup: We once had an indoor substation shut down to replace a bad 25kV PT. Somehow a city inspector got wind that there was "power off to a building for electrical repairs." He demanded to inspect the job before we re-energized. He walked in all gruff, spoiling for a fight, took one look around at all the OCBs, air-breaks and insulators; his eyes got as big as dinner-plates and he stammer _"I... I think this out of my jurisdiction!"_ I thought I was gonna die laughing. :laughing:
> 
> -John


Work for a utility? With a pension plan? I wish. Just a lowly inkineeeeer trying to scratch out a living.
________________________________________________

At Arc 'n Spark Electric our motto is "You dream 'em up, we put 'em up."


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## Big John (May 23, 2010)

Bkessler said:


> There wasn't enough room for a 90 and he could afford lb's. Seems like you should have a top hat made or installed.


 The funny part is that this is almost a straight shot, they don't even need 90's or LBs. If they'd designed their rack differently, they might have even been able to drop right into the gear without any offsets.

Nuts to building a top hat. 300.18 is pretty clear. If they want to get paid, they can come back and pull the conductors back out of the gear and install some greenfield on the ends.

Funny how it's never possible to do it right the first time, but the second time.... :icon_rolleyes:


Shorty Circuit said:


> Work for a utility? With a pension plan?


Don't feel too bad, the best they do for us is a 401k.

-John


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## B4T (Feb 10, 2009)

You need to take some pictures so we know what your talking about.


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## Big John (May 23, 2010)

Black4Truck said:


> You need to take some pictures so we know what your talking about.


 I can get some shots of it, but it's not gonna show you much that I haven't described: A rack of vertical 4" rigid conduit. Stops 4' feet above a piece of switchgear. The 750MCM continues out of the pipe down into the top of the gear.

-John


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## B4T (Feb 10, 2009)

Big John said:


> I can get some shots of it, but it's not gonna show you much that I haven't described: A rack of vertical 4" rigid conduit. Stops 4' feet above a piece of switchgear. The 750MCM continues out of the pipe down into the top of the gear.
> 
> -John


 
A picture is worth a thousand words, the guys on this site just love going over a pic looking for even one blade of grass out of wack :jester:


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## 480sparky (Sep 20, 2007)

Black4Truck said:


> .......even one blade of grass out of wack :jester:


'Specially when there's grass where there shouldn't be. :laughing:


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## B4T (Feb 10, 2009)

480sparky said:


> 'Specially when there's grass where there shouldn't be. :laughing:


 
My point exactly


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## Innovative (Jan 26, 2010)

480sparky said:


> 'Specially when there's grass where there shouldn't be. :laughing:


The grass is ok, its the boxes that are not supposed to be where they are.


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## danickstr (Mar 21, 2010)

Thhn has to be enclosed. Not just hung in free air. That is what enclosures means. The reason the word fitting is in there is because a fitting is a part of the enclosure.


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## RIVETER (Sep 26, 2009)

danickstr said:


> Thhn has to be enclosed. Not just hung in free air. That is what enclosures means. The reason the word fitting is in there is because a fitting is a part of the enclosure.


I agree here. I have only run triplex from cable trays to cabinets. Individual conductors should be in raceways.


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## John Valdes (May 17, 2007)

So, Whats the contractor got to say about this? Are you going to let it go? I am curious as to how this will be explained.


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## Big John (May 23, 2010)

John Valdes said:


> So, Whats the contractor got to say about this? Are you going to let it go? I am curious as to how this will be explained.


 Yeah, you and me both. I haven't tackled it, yet. Tuesday I'll probably be getting in there to take some photos, and I'll upload a couple for you guys as well as any sufficiently funny excuses from this EC. 

EDIT: I have a theory about what they'll tell me: We have some very old generators in the plant where this was run, and when those gennys were installed in 1930-whatever, this was the connection method: Stop the pipe before above each unit and just free-air. 

I'll bet these guys took one look at that and just latched onto it as a cheap and easy way of installing this. Problem is, regardless of whether _we're_ required to follow code, their job scope called for a code-complaint install, and they're a licensed EC. 

Do not pass Go, do not collect $200.

-John


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## 10492 (Jan 4, 2010)

I have seen Thhn in cable trays.

Motor centers were below with pipe or selatite ran up to the tray with connectors and bushings on them. The Thhn was neatly spaced and secured to the tray.


This was in a pretty decent size lumber mill that produces pallets.

Beautiful tray and pipe work. all inspected I'm sure.

After reading this thread, why is this non code compliant?


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## jwjrw (Jan 14, 2010)

Dnkldorf said:


> I have seen Thhn in cable trays.
> 
> Motor centers were below with pipe or selatite ran up to the tray with connectors and bushings on them. The Thhn was neatly spaced and secured to the tray.
> 
> ...


 

Cable trays are a different animal and have their own rules to follow.


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## Mogie (May 26, 2010)

Big John said:


> Yeah, you and me both. I haven't tackled it, yet. Tuesday I'll probably be getting in there to take some photos, and I'll upload a couple for you guys as well as any sufficiently funny excuses from this EC.
> 
> EDIT: I have a theory about what they'll tell me: We have some very old generators in the plant where this was run, and when those gennys were installed in 1930-whatever, this was the connection method: Stop the pipe before above each unit and just free-air.
> 
> ...


I'm interested to see these photos. Did you get any yet? I have done something similar myself, but had high hats fabricated for the purpose, and ran the diagrams by the inspector first for approval. He agreed that the high hats themselves would then be an integral part of the switch gear, as the top plates were permanently removed. In my case, however, the conduits were buried in 20" of concrete, and 90'd down over the gear in the only space that was available to me (rebar mats, drain lines, etc.), with very little clearance above the gear. It was physically impossible to install nipples or Greenfield between the riser 90s and the gear.
I would never install what you describe from a cable tray or ladder rack.


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## cdnelectrician (Mar 14, 2008)

What is a "high hat"???


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## 76nemo (Aug 13, 2008)

mattsilkwood said:


> I have seen it done that way one time. There was a tray above the gear and the various feeders dropped about two feet into the gear.
> That part didn't bother me too bad but they had the service conductors done the same way. They were piped from the tranny up an outside wall, then through the wall just above the cable tray and free air into the gear.
> I have no idea if it was legal or not, it wasn't part of our work so I never really gave it a second thought.


No freakin' way, service supply in free air???????????????????????????????


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## Mogie (May 26, 2010)

cdnelectrician said:


> What is a "high hat"???


 A high hat is sort of a generic term referring to a custom prefabricated sheet metal piece equivalent to the gauge the gear is made from. It's purpose is to extend the plane of the gear for the purpose of conductor protection,or is sometimes used for aesthetic reasons.


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## Big John (May 23, 2010)

So, I promised photos, and photos you shall have:

















There are a couple of different of ways to legally run cable exposed like that. These guys just didn't pick one of them. (Yeah, I know the place is a wreck. The station has been out-of-commission for years, this is part of the attempt to get it operational again.)

-John


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## McClary’s Electrical (Feb 21, 2009)

Big John said:


> So, I promised photos, and photos you shall have:
> 
> 
> 
> ...


 

Thanks John, a picture is worth a thousand words. I thought the conduits were running horizontally. I can't believe they didn't just finish the run in GF. 

Is that rope supporting the cable after it leaves conduit?


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## Bkessler (Feb 14, 2007)

wow, looks like he was just short 4 couplings and about 16' of pipe and needed to make his tee time. That's terrible.


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## oldtimer (Jun 10, 2010)

Big John said:


> So, I promised photos, and photos you shall have:
> 
> 
> 
> ...


 Pics are great. Do you have a pic showing the cables entering the equipment? Everything was done neatly, I just wonder why it was not finished.


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## Big John (May 23, 2010)

mcclary's electrical said:


> I can't believe they didn't just finish the run in GF.


That was my reaction, too. I'm sure it the look on my face was priceless when I first saw that.


> Is that rope supporting the cable after it leaves conduit?


There's no rope involved (thank god) but you might be seeing the bonding jumper they ran from the gear to the bond-bushings.


oldtimer said:


> Do you have a pic showing the cables entering the equipment? Everything was done neatly, I just wonder why it was not finished.


I can get them (and I'll probably have to if the EC disputes the change) but I didn't feel like hauling myself up there this morning.

It's "neat" but it's pretty mediocre electrical work, even ignoring this hiccup. I'm not a fan of the way they supported the pipes, either, but I'm willing to let that slide: The outside row of pipes is actually attached to the inside row, and the inside row is attached to the wall.

-John


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## 10492 (Jan 4, 2010)

Wow..

I'd be afraid them pipes are gonna fall, the way it appears to be supported. That's a bit of weight there with 750's in them.


That work is just soooooooo wrong.


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## 10492 (Jan 4, 2010)

Mogie said:


> A high hat is sort of a generic term referring to a custom prefabricated sheet metal piece equivalent to the gauge the gear is made from. It's purpose is to extend the plane of the gear for the purpose of conductor protection,or is sometimes used for aesthetic reasons.


 
A big custom made J-Box?


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## Shorty Circuit (Jun 26, 2010)

The wire looks like it came out of a salvage yard with about 20 years of dust and grime on it. I'd guess it had been used on a previous job somehow. It also looks like the installer used bonding jumpers to ground the conduit to the enclosure for the load. My specs always call for new material unless it is unavailable or supplied by the owner which in this case doesn't apply.


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## John Valdes (May 17, 2007)

Looks easy enough to fix. The conductors look long enough.


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## Mogie (May 26, 2010)

Dnkldorf said:


> A big custom made J-Box?


Kind of - but the area from the conduits to the gear itself is usually open, often with a removable cover.


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## Mogie (May 26, 2010)

Big John said:


> So, I promised photos, and photos you shall have:
> 
> 
> 
> ...


 Thanks for the photos, John. This does seem unbelievably lazy to me. With the 90s above, it's not like they'd be working both ends against the middle...


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## Big John (May 23, 2010)

Shorty Circuit said:


> The wire looks like it came out of a salvage yard with about 20 years of dust and grime on it.


That dirt is the result of work going on in the station, but it re-enforces the need for that raceway to be complete: If the conductors were protected they wouldn't be getting covered in crap.

-John


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