I have a 2.5 car garage with an array of flourescent lights on the ceiling.
There is one switch by the side door which turns the lights on. I want to
add a 2nd switch on a wall about 30' away on the other side of the gargage
(across the 2.5 bays). I'm clear on the wiring of the 3 way switches,
bought 2 & tested them at the existing switch with clip leads, my question
involves the proper way to run the wire across the garage to the new switch.
The garage is drywalled. My plan is to run 14/3 w/ground romex behind the
drywall to the existing switch box, replacing the current switch with a 3
way. At the ceiling above this box, the wire would exit the wall, and run
across the surface of the ceiling. Since the joists run perpendicular to
the course of the wire, it would be a pain routing the wire under the
drywall. The wire would then enter the wall across the garage and run down
behind the drywall to a box I will install there with the 2nd 3 way.
Easiest thing would be to simply staple the wire to the ceiling using the
proper fasteners. I can't imagine a scenario where this would be a hazard
or problem, but I'm not sure it would be "code", which may be an issue if I
sell the place. An alternative would be to run the wire through conduit as
it passes out of/into the 2 walls, and where it crosses the ceiling, which
of course would add expense & work. Anyone know if the staple approach
would be a code issue?
Yes, it wouldn't be code as can't have exposed Romex in habitable space.
Conduit would add some, but not a lot of work, and certainly not a
whole lot of expense.
I'd wonder that there isn't attic access above the ceiling in the garage
and why not simply go up there and pull the Romex where, one would
presume, the existing wiring is...
Thanks for the reply. There's living space above the garage, no attic. A
garage is considered habitable space? In my previous house the garage had
unfinished walls, no drywall just studs. The wire was all exposed. Same
with the basement ceiling (walls were block, wiring to outlets was in
conduit) A factor of its age, I guess (built mid-50's).
I have about 100' of 3/4" PVC pipe which I could use instead of the conduit.
Would this be considered sufficient?
Rules are different these days. And drilling thru studs makes
Not unless it's PVC electrical conduit. The grey stuff with appropriate
markings. It's < $10 per 10' length IIRC.
[We can reduce wire burial depth by enclosing in CSA approved black
flexible PVC tubing (the higher pressure irrigation stuff), but that
doesn't apply here, and that's a Canadian, not US, rule also.]
Age and Treachery will Triumph over Youth and Skill
Garages are not generally considered habitable spaces, however,
electrical code fairly specifically addresses the use of exposed
romex where it's subject to snagging. Surface mount on a garage
ceiling would be normally considered to be a snag hazard.
As dpb says, plastic PVC electrical conduit is cheap and easy to work
with. I used it for surface wiring on walls in a workshop, and
the inspector was quite happy with it. On the ceiling, since
the ceiling had lathe on it for later applying drywall, it was
okay to run it parallel to the lathe across the bottom of the joists,
where it had to cross lathe, I simply had to put a short length
of more lathe above the existing lathe to get the wire > 1.25" away
from the nailing surface.
Attic wiring has rules of its own, eg: in areas with more than 36"
(IIRC) of headroom you're not supposed to have the wire snaggable
(by running over the joists or under the rafters), the preferred
approach is along side the joists/rafters, and going across the
joist line at where the roof is lower, or protect it somehow.
Conduit is probably a whole lot easier.
Age and Treachery will Triumph over Youth and Skill
The use of PVC conduit exposed inside a building is generally a
violation of the building code. The "Smoke Contributed" rating of PVC
is far too high for this kind of use. Metallic conduit or Electro
Metallic Tubing using factory made bends is nearly as easy to work with
and provides better protection to the conductors. I would think that
the simplest way to do what the OP wants to do is to install an
extension ring over the existing switch box and use a knock out in the
extension ring to begin a run of EMT to a surface mount switch box on
the other side of the garage. If the ceiling is smooth it will only
take two box offsets and two ninety degree bends to route the EMT which
should make for a fairly easy wire pull.
But what are the restrictions on where exposed work is allowed?
My understanding which may be wrong was that normally accessible areas
on finished walls, ceilings etc., wasn't allowed to be openly exposed
w/o protection....somebody else noted there's alternate for high
headroom that the garage might be but iiuc it still would need
protection of some sort...
Thanks for the continued input on this. The ceiling height is 8'. About 2'
to the side of the straight-line path across the ceiling between the 2
switch locations is an enclosed beam about 8" wide which protrudes down 14".
I could run the wire at the 90 degree junction where this beam meets the
ceiling, providing additional protection. It's hard to imagine any
real-life situation where a cable so located might be damaged.
I know the conduit is relatively cheap, but even at ~$1/foot it would
probably add around $40-$50 to the project when all is said & done. Hardly
enough to break the bank, but if it's an unnecessary expense, why spend it?
Because it's the right way? :)
I agree there's not likely to be any safety issue but as you already
noted, come time you decide to sell, you can almost count that the
inspector will jump on exposed wire. While again, it wouldn't take much
to fix it at that point, that's a time likely it will be even less
convenient to deal with it. Besides, imo, it just looks tacky...
imo, $0.02, etc., etc., etc., ...
Well I guess I should actually PRICE the material before griping about it!
;-) Was expeceting more like $1/foot. I have to pick up the wire, will
look at the conduit options when I do. Thanks again for all the helpful
The Code doesn't say that. It says, "In exposed work ... cable shall be
protected from physical damage where necessary by rigid metal conduit,
intermediate metal conduit, [etc.]" and does *not* define any particular
locations where such protection is necessary.
[2005 NEC, Article 334.15(B)]
334.15(A) requires that exposed cable "closely follow the surface of the
building finish or of running boards". Seems to me that as long as it's
stapled securely to the ceiling of the garage, it's compliant.
That probably depends on the local inspector's judgement of the necessity of
protecting the cable from physical damage.
Doug Miller (alphageek at milmac dot com)
So it becomes a local inspector's opinion of whether this is "necessary"
or not. Might as well go ahead and make the neat installation from the
git-go, but I'll agree he _might_ get away with it...
Not explicitly required by code... ;-)
This may be of interest, from the electrical wiring FAQ
Protection for cable in concealed locations: where NM or AC cable
is run through studs, joists or similar wooden members, the outer
surface of the cable must be kept at least 32mm/1.25" (CEC & NEC)
from the edges of the wooden members, or the cable should be protected
from mechanical injury. This latter protection can take the form of
metal plates (such as spare outlet box ends) or conduit.
[Note: inspector-permitted practice in Canada suggests that armored
cable, or flexible conduit can be used as the mechanical protection,
but this is technically illegal.]
Additional protection recommendations: [These are rules in the
Canadian codes. The 1993 NEC has many changes that bring
it close to these rules. These are reasonable answers to the
vague "exposed to mechanical damage" in both the NEC and CEC.]
- NM cable should be protected against mechanical damage
where it passes through floors or on the surface of walls
in exposed locations under 5 feet from the floor.
Ie: use AC instead, flexible conduit, wooden guards etc.
- Where cable is suspended, as in, connections to furnaces
or water heaters, the wire should be protected. Canadian
practice is usually to install a junction or outlet
box on the wall, and use a short length of AC cable
or NM cable in flexible conduit to "jump" to the appliance.
Stapling NM to a piece of lumber is also sometimes used.
- Where NM cable is run in close proximity to heating
ducts or pipe, heat transfer should be minimized by
means of a 25mm/1" air space, or suitable insulation
material (a wad of fiberglass).
- NM cable shall be supported within 300mm/1' of every box
or fitting, and at intervals of no more than 1.5m/5'.
Holes in joists or studs are considered "supports".
Some slack in the cable should be provided adjacent to
each box. [while fishing cable is technically in violation,
it is permitted where "proper" support is impractical]
- 2 conductor NM cable should never be stapled on edge.
[Knight also insists on only one cable per staple, referring
to the "workmanship" clause, but this seems more honoured
in the breach...]
- cable should never be buried in plaster, cement or
similar finish, except were required by code [Ie: cable
burial with shallow bedrock.].
- cable should be protected where it runs behind baseboards.
- Cable may not be run on the upper edge of ceiling joists
or the lower edges of rafters where the headroom is more
than 1m (39").
[the last item applies to basements ceiling joists too]
BX is sometimes a good idea in a work shop unless covered by
solid wall coverings.
In places where damage is more likely (like on the back wall of
a garage ;-), you may be required to use conduit, a
UL- (or CSA-) approved metal pipe. You use various types of
fittings to join the pipe or provide entrance/exit for the
From another section:
Note that some jurisdictions have a "no horizontal wiring"
rule in workshops or other unfinished areas that are used
for working. What this means is that all wiring must be
run along structural members. Ie: stapled to studs.
Age and Treachery will Triumph over Youth and Skill
Why dfon't you simply do the job in Wiremold? Any box store has it,
it's neat, simple, tidy, looks professional and it's quick to install.
Price is reasonable and best of, it's code! Look around in many
commercial buildings, you'll see it used as a problem solver for new
equipment and remodels. Odds are you've looked right at it and never
really noticed. Many journeyman have it on the truck for those
aggravating problems that need to be solved yesterday. HTH
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