"Romex" is a brand name. The 12-2 NM-B specification is more important
than the brand name. (12-2 will support up to 20 amps for typical runs).
I used the term Romex as that's how most folks refer to it, even though
it may be made by other manufacturers. Just like tissues are often
called "Kleenex", even though many other companies make them.
That sounds OK to me. Based on the correction "Bud" supplied, you could
run a single NM-B cable in the large conduit now. If you ever need to
run additional lines, you could pull that cable, install junction boxes
top and bottom, and run individual wires in the conduit. Or, go ahead and
transition now to save future work.
Better yet, dedicate the 1-1/2 inch line to data needs, and install
additional 3/4" conduit runs for future power runs. I would cap any
unused lines to keep out insects and drafts.
Oh, and just for clarification, make sure you use grey colored PVC
"conduit" and not white PVC water pipe. You wouldn't want someone cutting
into what they think is a water line, only to cut into power or data
I mounted in-wall speakers in our living room, but did not use conduit
for those lines. It's unlikely I would ever need to relocate the
speakers, and if I did it would involve drywall work anyway. But, if you
plan to move things around often, or future access would be difficult,
the conduit will really make things easier.
Note: If you run speaker cables in the wall, make sure you use speaker
cables listed for that purpose. I think it's "CL-2" cable with a fire
retardant outer jacket that also makes it easier to pull.
I installed a double-gang sized box on each wall of our living room and
every bedroom, with two 3/4" conduits running to our crawlspace. These
are for data purposes only. It's not always easy to forsee how furniture
might be moved around, and it's not a big cost to add a few more boxes to
simplify changes later.
A few of the boxes have gone unused, but I've been surprised how much
I've needed most of them. I've run cat5 cables through most of them to
connect the computers in various rooms. Two other cat5 cables run to our
living room for my blu-ray player and a network media streamer (lets me
watch TV shows recorded on the PC in my office).
Install blank cover plates on the boxes you don't use. Special plates
with "keystone" jacks let you run all sorts of connections. For
instance, the box in my office has two cable lines (one from cable TV,
one from an outdoor antenna), two phone lines, and two cat5 ethernet
There isn't anyplace in the house I regret installing the boxes, but I do
wish I had installed additional boxes in the home-office, our bedroom,
and even the kitchen. I quickly ran out of ports for my home network, so
I worked around that by installing a network switch in the crawlspace (I
was fortunate to have a power outlet available there). I didn't forsee
the need to run much data to the bedroom, so I didn't plan ahead well
enough there. I've already had to fish a couple of extra cables in the
last five years. A box and conduit would have made things much easier.
Of course, about a month after I ran network cables to every room, I
bought a wireless router and don't need the wired connections for my
laptop now. :) But the wired connections are still used between desktop
PC's and the media devices in our living room. Nice thing about the
conduit, I can easily pull out the unused network cables and feed
something else in if my needs change later.
Thanks for all that information.
Heck, I was going to run 4 of the 12-2 NB wires through that 1-1/2
inch by 10 ft long pipe. It is the gray pipe used for electrical runs,
btw. Looks like that could be a problem, eh?
(4) is the maximum number of 12-2 NM-B cables you can bundle together
(e.g. run through a sleeve like you are doing) and still maintain the
20 amp capacity (assuming no other correction factors, like elevated
ambient temperature). So you are fine, just don't put a 5th one in
there. As for the sleeve, you can use whatever material is
Oops, I need to amend that. The one wrinkle is that you normally have
to support your NM cable every 4.5 feet (NEC 334.30). The allowable
exceptions are (1) you are doing remodel work and fishing the cable
(NEC 334.30(B)(1)) or (2) you are running the cable inside a raceway
(the NEC term for conduit) that provides protection from physical
So, if your wall is open, and you are installing a sleeve and running
NM cable in the sleeve, then you have to use a raceway, like PVC
electrical conduit. But if you are doing remodel work, and come
across an existing unused pipe in a finished wall, you can fish your
wire down it without regard to what the sleeve is made of.
OK, so running four 12-2 NM B cables in the 1-1/2 inch conduit. Again,
I already have the gray conduit specifically meant for electrical.
I am not sure how I can support the wire every 4 1/2 feet inside the
conduit. How is that done? The whole of the 10 feet of conduit will be
Also, what is a good way to tag the wires so I would know what each
wire goes to as they exit the conduit?
"344 Non-metallic sheathed cable: Types NM, .... [commonly called Romex]
344.30 Securing and Supporting.
...4 1/2 ft...12 inches....
Sections of cable protected from physical damage by raceway shall not be
required to be secured withing the raceway."
I would think an inspector would view a raceway used to fish cables the
same as one used for physical protection.
Can't remember if "raceway" has been defined in this thread, but it is a
hollow wiring method installed without wires that wires are added to -
like PVC conduit.
A sharpie pen works great for writing identifications on the outer covering
of NM-B cables. If you're feeding multiple cables at once, you can write
the ID on the cables first, then feed them through the conduit, something
that wouldn't work well with adhered tags or labels.
You do not usually need to support cables in a conduit, certainly not
every 4 1/2 feet. There are rules about vertical runs but for copper
18ga thru 8 ga it is a vertical run over 100' that needs supplemental
Electricians usually use different colors of tape to identify cables
Maybe I missed something here, but based on what Wayne and Bud said,
it sounds to me like you could run four 14-2 Romex through a single
"In terms of overheating, you need to watch how many current carrying
conductors (CCCs) you run together for a significant length. If you
have too many together you have to "derate" each conductor so that it
carries less current, or alternatively upsize the conductor for a
given current. The rules are complicated, and derating potentially
starts at 4 CCCs. However, for NM cable in #14 and #12 sizes, you can
run up to 9 CCCs and still maintain the usual 15A and 20A capacities,
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