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Disconnect distances #9552 05/02/02 07:23 PM
Joined: Jan 2002
Posts: 38
BrianSparky Offline OP
Okay all you inspectors,
Can anyone site me a code reference that requires placing a disconnect for a roof top unit at least 3' away from a gas line?
We recently had someone gigged for this and now I'm having to hook up 4 RTU's.
Second question: coming up out of the old pipe (thru roof jack), I'm going to set a Nema 3 j-box on top of the old pipe (which I'll cut at approx 2') which will then feed the new disconnect with sealtight. My question is: Do I need to secure the j-box independtly from the 2' pipe to the roof?
Thanks and spark on!

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Re: Disconnect distances #9553 05/03/02 02:08 PM
Joined: Apr 2002
Posts: 2,527
Bjarney Offline
“…disconnect for a roof top unit at least 3' away from a gas…” Blame it on “Regional Variations.” Then, ask for a citation.

…secure the j-box independently from the 2' pipe… That’s a good use for framing channel, with color-coordinated brackets and spring nuts. I’ll bet for a moment someone even toyed with the idea of putting splices in the floating box too. Article 370…–23(e).

Re: Disconnect distances #9554 05/04/02 08:42 AM
Joined: Jul 2001
Posts: 311
Frank Cinker Offline
Who is requesting that your disconnect be located at least 3ft. from gas line? What NEC article did he quote?

Re: Disconnect distances #9555 05/04/02 09:22 AM
Joined: Jan 2001
Posts: 1,044
Tom Offline
This has to be a mechanical code thing 'cause it sure isn't a problem with the NEC, provided, of course, that the pipe in question is outside the work space.

Few things are harder to put up with than the annoyance of a good example.
Re: Disconnect distances #9556 05/04/02 09:45 AM
Joined: Jan 2002
Posts: 38
BrianSparky Offline OP
Thanks for the replies!
Upon further research, I found this was enforced in another city/jurisdiction, (wasn't my job, my apprentice told me about this instance).
A little more history: I built unistrut racks to mount on the flat roof (concrete with rubber membrane) and was going to use hollow wall anchors to bolt the bases to the roof...when I had my helper start bolting these to the roof, we found out that the anchors wouldn't set and pulled out! [Linked Image]
I finally called the local inspector for the city I was working in and he told me it was okay to mount the disconnect directly to the RTU providing I didn't cover any access panels! (Some people do have common sense after all!) [Linked Image]. Anyway, he didn't have any problem with gas line distances, etc.
As far as supporting the j-boxes, any suggestions?
I thought of using pipe stands (you know, the aluminum ones) and strapping the j-box pipe to them, but this seems more cosmetic than anything, a strong wind would seem to just blow this over.
And further on, I have a big disconnect to mount later on (3phase 150A) and I don't see any available space on the RTU.
Any suggestions would be greatly appreciated, but remember the problem with the roof top. Now if I can sweet talk the roofers so they don't kill me....

Re: Disconnect distances #9557 05/05/02 09:33 PM
Joined: Jan 2002
Posts: 163
dana1028 Offline
Brian -

you said something about needing a nice place for your upcoming panel install...and there will be a new roof?

Get with the roofers about sticking some nice 'sleepers' up there (4x4x10 ft press. treated)...the roofers will finish the sleeper curbing when they do the roof and you have a nice base for plenty of panel work...we have (6) 480v, 200A boards on our roof, all mounted to sleepers using strut & diagonal strut bracing.

Re: Disconnect distances #9558 05/06/02 11:23 PM
Joined: Jan 2002
Posts: 38
BrianSparky Offline OP
Thanks for all your replies...
Dana, great idea, I'll try it sometime in the future, but this isn't a new roof.
Anyway, we came up with a solution for the 150A 3 phase panel.. we mounted 2 pieces of deep strut on the front of a panel and extended it out beyond the RTU, enough to mount the panel on spring nuts, worked great!..lets see if the inspector likes it!
Thanks again..


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