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#3300 08/15/01 06:37 AM
Joined: Aug 2001
Posts: 58
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ken m Offline OP
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i worked the industrial side of the business most of my life (30yrs) and doing the residential on weekends and such. finally decided to retire into res. only. suprise! anyway, i have a question regarding a post in the photo section of the forum. why can't the header above the dist panel (flush mount) be drilled to allow a conduit with branch circuit cables to pass through?
another question; is there a size limit on the nm feeder cable, to a panel that is run between 2x4 studs unprotected by conduit? (top or bottom entrance to the panel)
thx for any feedback. ken m

#3301 08/15/01 11:23 AM
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#3302 08/15/01 12:30 PM
Joined: Aug 2001
Posts: 58
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ken m Offline OP
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hey sparky, yes that is the one. i have seen different methods. i.e., several holes drilled in the header and individual clamps at the box, like the photo portrays and a 2' or a 2-1/4" pvc or emt conduit run from the panel thru the header an the branch cables passing thru. i'm familiar with the 24" nipple rule and max # of cables. are there any other reasons why the conduit thru the header is not nec worthy?
providing the cables are secured prior to entry into the conduit and a sealer is used. thx., ken m

#3303 08/15/01 05:10 PM
Joined: Jan 2001
Posts: 1,044
Tom Offline
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Ken,

373-5(c) requires that "cables shall be secured to the cabinet..."

There is an exception for surface mounted cabinets, but there are 7 items that must be complied with to do it right.

As far as the max size cable is concerned, you have 1 inch in the center of a 2x4 to use without needing nail protection, see 300-4(a). You might, if you hold your mouth just right, get #2 aluminum SER cable to go through a 1" hole. I certainly wouldn't want to run this size cable through too many holes, my back hurts just thinking about it. [Linked Image]

Tom


Few things are harder to put up with than the annoyance of a good example.
#3304 08/15/01 08:02 PM
Joined: Nov 2000
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Uh...

We're allowed to go larger then 1" if we use "anti-nail plates" though, right? I get mine at a hardware store, the type plumbers use...

What about protection between the framing members (in the stud-bay voids) ? Do we have to sheet the entire run with 1/16" Galvanized steel?


-Virgil
Residential/Commercial Inspector
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#3305 08/15/01 08:09 PM
Joined: Oct 2000
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are there any other reasons why the conduit thru the header is not nec worthy?
providing the cables are secured prior to entry into the conduit and a sealer is used.


I don't know the rationale behind this particular code. It would seem a captive panel would be accessible if it were so.
[Linked Image]

#3306 08/15/01 08:11 PM
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Good point Virgil,

We should use diamondplate on the outside to protect from the siding guys !
More than once I've seen them nail right through the panelboard into the Busbars! And once put a screw into the SE cable (Underground service). Like the 4th of July!!

Bill


Bill
#3307 08/15/01 08:58 PM
Joined: Apr 2001
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Be careful about using a plumber's nailplates. They may be too thin. UPC requires steel plates to be not less than 18 gauge.That's .0478" instead of .0625"

#3308 08/15/01 10:03 PM
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Good point Phil!


Bill

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