Mains wiring question (USA)

wrote:


<snip>
It sure is, inside buildings. Once you go outside it tends to be RMC (aka GRC). Though rigid PVC (aka RNC) is quite common also.

My experience is different.

I hardly ever see that used.

If you want to get specific about the case i can look it up in my copy. I have 2005 here at home and 2008 at work.

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On Tue, 24 Aug 2010 18:39:45 -0700,

This is probably what you are thinking about (300.4(A)(1) is a similar rule about bored holes)
300.4(A)(2) Notches in Wood. Where there is no objection because of weakening the building structure, in both exposed and concealed locations, cables or raceways shall be permitted to be laid in notches in wood studs, joists, rafters, or other wood members where the cable or raceway at those points is protected against nails or screws by a steel plate at least 1.6 mm (1/16 in.) thick, and of appropriate length and width, installed to cover the area of the wiring. The steel plate shall be installed before the building finish is applied.
Exception No. 1: Steel plates shall not be required to protect rigid metal conduit, intermediate metal conduit, rigid nonmetallic conduit, or electrical metallic tubing.
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I see a lot more EMT on the outside of buildings than rigid, unless you are near the ground where the pipe may be hit by cars.

I seldom saw rigid on the construction projects I was on. It is good for some uses, like hazardous - gas stations, refineries....
Digging out a construction estimator, rigid is about twice the cost, installed, as EMT.

No need to look it up - I know what the NEC says. It is what gfretwell posted, which is the same as what I said.
-- bud--
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wrote:

--
Yup, you're right.

Thanks for the reality check. :-)
  Click to see the full signature.
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John Fields wrote:

No it is not.
rigid is like water pipe..
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No, emt is 1/16" thick and uses fittings, while rigid is 1/8" thick and is threaded.
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On Mon, 23 Aug 2010 13:40:43 -0500, John Fields

John F., there is significant wall thickness differences between EMT, IMC, and GRC. NOT the same. For more see NEC articles 358 EMT, 342 IMC, and 344 RMC. Or use your favorite search engine with the added info i just provided.
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Bob E seems to have left the discussion.I Hope he uses coded mAterials and the proper conduit for the run he is attempting.... The engineering machine seems to have gotten into a piss match with the inspector. I did get it's smarts revolving the serviced entrance being the location n use.Why did he even have to ask? Who runs bare Cable, UF or Romex over a wooden surface, wasn't it outlawed in the electrical safety code updates.
RR
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Specifically Romex, UF ect. for Exterior Locations is a No No.. The Exception being Temporary Wiring for Lighting et al. RR
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Randy Type UF cable, that is Sunlight resistant, is perfectly acceptable outdoors. It is very commonly used under decks, behind gutters & downspouts, and anywhere else were it's appearance is acceptable to the owner and it is not subjected to physical damage from such things as materials handling, lawn care equipment, motor vehicle movement and so fourth. Multi conductor type UF is only available as sunlight resistant so that is seldom an issue. Single conductor type UF is only intended for use underground or in raceway when above ground and is not presently manufactured in sizes smaller than four American Wire Gage. You are correct in saying that Romex, or any other brand of Type NM cable for that matter is not permitted outdoors but running it inside a roofing assembly does not make it an outdoor use. -- Tom Horne
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The usual good information from Tom.
The usual bad information from Randy, aka Proteus, aka Roy, aka Roy Quijano.
-- bud--
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Yawnnnn... oh Budkins get a life.., Everyone is Roykins to you. You sound just like the Trolls that accosted this group..He owe you something?
RR
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Actually I have it from good authority that they have Proteus on LockDown doing surveilannce on the ISS and some thermal imagery on some classified locations, probably not on earth... Roy is a mystery, as far as I know...best left alone unless you want to see hardcore G-men in action :)
RR
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I don't want to start a pissing match over this, but It is illegal for any outdoor use in major cities, you country folk and rural or suburban home owners wouldn't know this.
It is hilarious the way they drape it over the sides of their homes., like it is ok.
RR
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OK. So don't start anything. Just site two major city codes, other than Chicago and environs which essentially forbid all cable, that forbid the use of exterior UF. -- Tom Horne
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In article

For actual protection you want EMT or armored cable. While this roof is a foam roof, there's no telling what the next roofing job (quite possibly not done by you) will put over it...
To make the inspector happy you ask the inspector what the inspector wants to see. As described by you, a 50 foot roll (or as many as you need) of 4-6" aluminum flashing ("sheet metal") would apparently suit the inspector, while providing no protection to speak of (and the delightful possibility that you manage to staple into the cable while trying to staple the sheet metal over the cable). Of course, if you do that without getting a specific clearance from the inspector that this is what he wants to see, he might come back and indicate that he actually wanted galvanized steel, not aluminum, and make you rip it all up. At which point using EMT looks a whole lot easier, as well as more effective.
--
Cats, coffee, chocolate...vices to live by

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EMT (electrical metallic tubing) is not considered protection for wiring, just tubing.
Use some square metal roof conduit designed for the job. It will probably stick up and not have anything stapled on top of it, Or put the wiring under the roof sheeting.
wrote:

For actual protection you want EMT or armored cable. While this roof is a foam roof, there's no telling what the next roofing job (quite possibly not done by you) will put over it...
To make the inspector happy you ask the inspector what the inspector wants to see. As described by you, a 50 foot roll (or as many as you need) of 4-6" aluminum flashing ("sheet metal") would apparently suit the inspector, while providing no protection to speak of (and the delightful possibility that you manage to staple into the cable while trying to staple the sheet metal over the cable). Of course, if you do that without getting a specific clearance from the inspector that this is what he wants to see, he might come back and indicate that he actually wanted galvanized steel, not aluminum, and make you rip it all up. At which point using EMT looks a whole lot easier, as well as more effective.
--
Cats, coffee, chocolate...vices to live by



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Bob E. wrote:

Where some types of wiring is near the edge of a stud and may be hit by a drywall screw the wiring needs to be protected by a 1/16" steel plate. I suggest you ask the inspector how heavy the "sheet metal" has to be. I don't know of a standard electrical item for the protection you need. I would ask at a company that makes ventilating ducts.
--
bud--

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On 8/16/2010 10:00 PM, Bob E. wrote:

The inspector is not crazy, just following the arcane rules like the good droid he is. You're looking for something like these:
http://www.garvinindustries.com/Electrical-Junction-Boxes/Cable-Protection/Cable-Protection-Plates/SP-3
They are typically used to protect cables and copper water pipes from drywall nails/screws. Probably find them at the local mega hardware store for not much money -- 19 cents each at the link above.
Like a few others, I'd vote for whatever type of conduit rocks your boat unless you're sure there will never again be the need for wiring mods.
Ken
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From the 2008 edition of the NEC: 300.4 Protection Against Physical Damage ...
(A) Cables and Raceways Through Wood Members.
(1) Bored Holes. In both exposed and concealed locations, where a cable- or raceway-type wiring method is installed through bored holes in joists, rafters, or wood members, holes shall be bored so that the edge of the hole is not less than 32 mm (1 in.) from the nearest edge of the wood member. Where this distance cannot be maintained, the cable or raceway shall be protected from penetration by screws or nails by a steel plate(s) or bushing(s), at least 1.6 mm (1/16 in.) thick, and of appropriate length and width installed to cover the area of the wiring.
Exception No. 1: Steel plates shall not be required to protect rigid metal conduit, intermediate metal conduit, rigid non-metallic conduit, or electrical metallic tubing.
Exception No. 2: A listed and marked steel plate less than 1.6 mm (1/16 in.) thick that provides equal or better protection against nail or screw penetration shall be permitted.
There is no provision to exempt type AC cable ("bx") from the nail-plate protection requirements.
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