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wiring methods #3300
08/15/01 07:37 AM
08/15/01 07:37 AM
K
ken m  Offline OP
Member
Joined: Aug 2001
Posts: 58
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

Work Gear for Electricians and the Trades
Re: wiring methods #3301
08/15/01 12:23 PM
08/15/01 12:23 PM
S
sparky  Offline
Member
Joined: Oct 2000
Posts: 5,360

Re: wiring methods #3302
08/15/01 01:30 PM
08/15/01 01:30 PM
K
ken m  Offline OP
Member
Joined: Aug 2001
Posts: 58
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

Re: wiring methods #3303
08/15/01 06:10 PM
08/15/01 06:10 PM
Tom  Offline
Member
Joined: Jan 2001
Posts: 1,044
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. [Linked Image]

Tom


Few things are harder to put up with than the annoyance of a good example.
Re: wiring methods #3304
08/15/01 09:02 PM
08/15/01 09:02 PM
sparky66wv  Offline
Member
Joined: Nov 2000
Posts: 2,236
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?


-Virgil
Residential/Commercial Inspector
5 Star Inspections
Member IAEI
Re: wiring methods #3305
08/15/01 09:09 PM
08/15/01 09:09 PM
S
sparky  Offline
Member
Joined: Oct 2000
Posts: 5,360
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]

Re: wiring methods #3306
08/15/01 09:11 PM
08/15/01 09:11 PM
Bill Addiss  Offline
Member
Joined: Oct 2000
Posts: 3,902
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

Re: wiring methods #3307
08/15/01 09:58 PM
08/15/01 09:58 PM
P
Phil H  Offline
Member
Joined: Apr 2001
Posts: 21
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"

Re: wiring methods #3308
08/15/01 11:03 PM
08/15/01 11:03 PM
Bill Addiss  Offline
Member
Joined: Oct 2000
Posts: 3,902
NY, USA
Good point Phil!


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