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#3300 - 08/15/01 04:37 AM wiring methods
ken m Offline
Member
Registered: 08/14/01
Posts: 61
Loc: south carolina
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
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#3301 - 08/15/01 09:23 AM Re: wiring methods
sparky Offline
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Registered: 10/18/00
Posts: 5545
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#3302 - 08/15/01 10:30 AM Re: wiring methods
ken m Offline
Member
Registered: 08/14/01
Posts: 61
Loc: south carolina
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
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#3303 - 08/15/01 03:10 PM Re: wiring methods
Tom Offline
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Registered: 01/01/01
Posts: 1069
Loc: Shinnston, WV USA
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.

Tom
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#3304 - 08/15/01 06:02 PM Re: wiring methods
sparky66wv Offline
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Registered: 11/17/00
Posts: 2342
Loc: West Virginia
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?
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#3305 - 08/15/01 06:09 PM Re: wiring methods
sparky Offline
Member
Registered: 10/18/00
Posts: 5545
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.
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#3306 - 08/15/01 06:11 PM Re: wiring methods
Bill Addiss Offline
Member
Registered: 10/07/00
Posts: 4196
Loc: NY, USA
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
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#3307 - 08/15/01 06:58 PM Re: wiring methods
Phil H Offline
Member
Registered: 04/14/01
Posts: 24
Loc: Tujunga, CA
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"
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#3308 - 08/15/01 08:03 PM Re: wiring methods
Bill Addiss Offline
Member
Registered: 10/07/00
Posts: 4196
Loc: NY, USA
Good point Phil!
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