Stapling wiring and electrical code.

I'm re-wiring some outlets etc. in an old house I own. The basement has an open ceiling and the old wiring is stapled along the bottom surfaces of the joists to get to the service panel.
For the new wiring, it is okay to staple the new wires the same way along the bottom surfaces of the joists adjacent to the existing wires that are already stapled there, or does the new wiring need to go through the joists?
And, for stapling wires in general, is it okay to staple two runs of wire using one staple, or does each run of wire have to be stapled separately?
I am trying to find out what the National Electrical Code (or whatever the national code is for the U.S.) says for both of these situations, but I can't seem to find anything on the Internet.
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No, yes, but...
Code prohibits exposed surface-mount wiring in habitable space. The existing isn't up to current Code either, of course. New should either be in conduit if run under or through or have a protective 1x on either side of the run to make a (upside down) cable tray for the protection is also still (I believe) compliant.

AFAIK, it's still ok if use properly sized staples.
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Just out of curiosity, does this follow the current derating rule about number of wires in a conduit? Say if you have three 14AWG 2- wire w/ ground cables stapled together, then that would count as 6 current-carrying conductors in the same conduit, etc?
Ken
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Yes, that's right, derating would apply.
But for the purposes of derating, you can start with the 90 degree ampacity of the conductors (for modern NMB), although the final ampacity can not exceed the 60 degree rating or for most circuits the small conductor limits (15 amps for #14, 20 amps for #12, 30 amps for #10). So the upshot is that unless you have 10 or more current carrying conductors, the #12 is still good for 20 amps and the #14 is still good for 15 amps.
Cheers, Wayne
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Thanks.
I just found a cool website that answers the question about wiring in an unfinished basement. I'm still searching regarding the stapling question and whether there is a code about whether 2 or more NM runs can be stapled with one staple.
The cool part about the website that I found is that it provides direct links to the National Electrical Code.
Here's the website link I found regarding the basement wiring:
http://www.howtowireahouse.com/House_Wiring_Electrical_Codes_Basement.html
Their main website is:
http://www.howtowireahouse.com

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As long as you don't squeeze the conductors, it should be fine to put two cables under one staple. For example, the insulated staple gun I use specifically says it is good for (2) 14/2 or (2) 12/2, although only one 14/3 or 12/3, since they are typically round.
One thing to know is that if you staple them together for a run of over 24", then most would consider them "bundled" and so derating would apply. However as my other post mentions, for small conductors in NMB cable, this has no effect until you reach 10 current carrying conductors.
Cheers, Wayne
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The same derating is required for an NM-style cable anyway since they're not single-wire in free air...
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The issue you raise is whether one can use NEC Table 310.17 for ampacity (Allowable ampacities ... in Free Air) as opposed to Table 310.16 (Allowable Ampacities ... in Raceway, Cable, or Earth).
The issue I'm referring to is when the derating factors in Table 310.15(B)(2)(a) apply, and then whether the derating factors make any difference, given the restrictions in 240.4(D) "Small Conductors".
Cheers, Wayne
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wrote:

Cite that
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IIRC, there is a height minimum so people don't use them as clothes lines. May be other exceptions also.
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? For the new wiring, it is okay to staple the new wires the same way along

Doesn't your Black and Decker book cover that?
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cavedweller wrote:

So far, I haven't found the answers in the B&D book. It does say in the 2-page section on common code requirements that one should not staple wires to the bottom of joists. But, it doesn't elaborate on what the options are for various wire sizes etc. I haven't found anything yet in the book regarding the question of whether 2 or more NM wire runs can be stapled with the same staple.
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It doesn't matter what the NEC says UNLESS your local codes say to adhere to the NEC and have not added their own little goodies to it. Call your code enforcement office; only they have the final answer for you, regardless of waht anyone here says.
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Through the joist is an option, often the best choice. You can nail a furring strip across the joists then attach the Romex to that. Or, you can use conduit across the bottom of the joists. If a clothes hanger (or work light) can be hooked onto the wire with the wire providing the support, then it is not properly installed.

You can staple multiple wires. There are various size staples.

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RonABC wrote:

Careful, I had an inspector fail my rough inspection because I had stapled the cables to the studs with wiring stapler. He said they were not UL listed. I showed him the box with the UL seal, and that just pissed him off and he said I still couldn't use them because they just weren't safe. (Why didn't he say that to begin with instead of lying to me about UL?)
I had to pull them all out and use plastic staples. It was a small job, and it was easier to do that than to appeal to a supervisor who might have also shot me down -- they don't like homeowners doing their own work here.
Bob
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