I put a pdf file on my website which shows my current thinking
about making an HTTN run through conduit. Evidentally, Rigid (EMT)
is a better choice than Flexible Metal Conduit. BTW, the EMT that is not
vertical will be on the ceiling; my SketchUp skills still need more
work. Please take a peek:
http://web.newsguy.com/MySite/
As you can see from my pictures, there are 3 electrical boxes--the
switch box mounted behind the wall and the other 2 bexes which are
surface mounted. The pictures basically show my current idea. I am left
with a question or two (if you would be so kind):
1. How is the weight of the vertical piece of EMT supported? It seems
that there would be quite a bit of weight on the switch box on the
bottom as I don't think the typical clamps that I've seen are designed
to prevent the EMT from sliding underneath them. Maybe I need special
clamps, extra support for the switch box, or something else?
2. I assume, that to attach the 2nd box (the one on the wall), that the
end of the EMT (bent at 90 degrees) is pushed through a hole, connected
to the box (with a screw-type connector) and then the box is screwed to
the stud through the wall. Please correct me if I am missing anything here.
At least I came up with a way to avoid working at the top-plate near the
eave (which I could not figure out how to deal with)!!! Thank you for
your patience!
Bill
P.S. Doug taught me a little about LL (and LB,LR) conduit body
connectors. These do not seem to make sense here unless you're want to
run the wire before you finish the drywall. No one would use one of
those in this model, would they?
Bill <[email protected]> writes:
>Scott Lurndal wrote:
>
>> --- Begin Quote ---
>>
>> Section 410-31 of the NEC (1999 Edition) states:
>>
>> Fixtures shall not be used as a raceway for circuit conductors.
>>
>> Exception #1: Fixtures listed for use as a raceway
>> Exception #2: Fixtures designed for end-to-end assembly to
>> form a continuous raceway or fixtures connected
>> together by recognized wiring methods shall be permitted
>> to carry through conductors of a 2-wire or multiwire
>> branch circuit supplying the fixtures.
>> Exception #3: One additional 2-wire branch circuit separately supplying
>> one or more of the connected fixtures described in exception
>> #2 shall be permitted to be carried through the fixtures.
>>
>> Branch-circuit conductors within 3 inches of a ballast within the ballast
>> compartment shall have an insulation temperature rating not lower than
>> 90 degrees C such as Types RHH, THW, THHN, THHW, FEP, FEPB, SA and XHHW.
>>
>> --- End Quote ---
>>
>> Most consumer grade flourescents aren't listed as raceways. That pretty
>> much leaves exception #2 as the guidance for this application. It also limits
>> you to 2 two-wire or 1 three-wire and 1 two-wire branch circuits for the
>> string of fixtures.
>>
>
>Scott.
>
>There is only 1 15A branch circuit. However, I had planned for it to
>"split" through 3 switches in the switchbox and pass the resultant 5
>wires--3 hot, 1 neutral, 1 ground, through the fixtures as necessary to
>power them. If I understand correctly, this would qualify as a single
>2-wire branch circuit, wouldn't it?
Yes. The extra wires in this case do not matter[*], since they'll sum to the
maximum branch circuit current (15a, in this case). This is would not be
considered a multiwire branch circuit, however, per article 100 and 210-4, which
requires a potential difference between the ungrounded conductors.
In other words, you have multiple paths for the same branch circuit.
scott
[*] subject to raceway fill guidlines.
On Tue, 23 Aug 2011 10:29:40 -0400, "Mike Marlow"
<[email protected]> wrote:
>Bill wrote:
>
>>
>> *This is neither an offer to sell nor a solicitation of an offer to
>> buy the light fixtures described above. An offering is made only by
>> the prospectus. The sales and advertising literature, and in
>> particular the LOW numbers, must be read in conjunction with the
>> prospectus in order to fully understand all of the implications and
>> risks of the fixtures to which the prospectus relates.
>>
>> A copy of the prospectus must be made available to you in
>> connection with any sale. No sale is made except by a prospectus filed
>> with the Department of Law of the State of New York. Neither Home
>> Depot, the Attorney-General of the State of New York nor any other
>> state commissions has approved or disapproved of these
>> fixtures or determined if the corresponding prospectus is truthful or
>> complete. Any representation to the contrary is a criminal offense.
>> (!)
>
>Huh???
Looks like a faulty cut-n-paste from the Lithonia website. OR, señor
Bill could have included it for fun.
--
It is characteristic of all deep human problems that they are
not to be approached without some humor and some bewilderment.
-- Freeman Dyson
Bill wrote:
> I put a pdf file on my website which shows my current thinking
> about making an HTTN run through conduit. Evidentally, Rigid (EMT)
> is a better choice than Flexible Metal Conduit. BTW, the EMT that is
> not vertical will be on the ceiling; my SketchUp skills still need
> more work. Please take a peek:
THHN - Not HTTN...
>
> http://web.newsguy.com/MySite/
>
> As you can see from my pictures, there are 3 electrical boxes--the
> switch box mounted behind the wall and the other 2 bexes which are
> surface mounted. The pictures basically show my current idea. I am
> left with a question or two (if you would be so kind):
So am I - why one flush box and two surface mounted boxes? If you're going
to run EMT, it's much easier to run it all surface mount. You can get
extensions to bring your existing flush mount box out so that it's the same
as your surface mounts if that's the issue.
>
>
> 1. How is the weight of the vertical piece of EMT supported? It seems
> that there would be quite a bit of weight on the switch box on the
> bottom as I don't think the typical clamps that I've seen are designed
> to prevent the EMT from sliding underneath them. Maybe I need special
> clamps, extra support for the switch box, or something else?
The box supports the vertical run. If the box is properly installed, it
will have no trouble supporting the riser.
You should spend some time doing google searches on bending EMT. There's
quite a bit of good You Tube material out there and you'll want to view it.
Make sure you understand how to properly measure for bends using the
indicators on your bender, and make sure you get a good handle on bending
offsets - you'll be bending quite of few of them.
--
-Mike-
[email protected]
Bill wrote:
>
> *This is neither an offer to sell nor a solicitation of an offer to
> buy the light fixtures described above. An offering is made only by
> the prospectus. The sales and advertising literature, and in
> particular the LOW numbers, must be read in conjunction with the
> prospectus in order to fully understand all of the implications and
> risks of the fixtures to which the prospectus relates.
>
> A copy of the prospectus must be made available to you in
> connection with any sale. No sale is made except by a prospectus filed
> with the Department of Law of the State of New York. Neither Home
> Depot, the Attorney-General of the State of New York nor any other
> state commissions has approved or disapproved of these
> fixtures or determined if the corresponding prospectus is truthful or
> complete. Any representation to the contrary is a criminal offense.
> (!)
Huh???
--
-Mike-
[email protected]
Doug Miller wrote:
> In article <[email protected]>, "Mike Marlow"
> <[email protected]> wrote:
>
>> In a residential setting, if you're not going to surface mount, then
>> there's no reason for EMT - just use Romex. It's perfectly
>> acceptable and equally good.
>
> Sorry, Mike, I can't agree with you there. This is going in a
> combination
> garage/shop, where an electrical inspector would probably consider
> the cable
> to be subject to physical damage, thus requiring that it be installed
> in
> conduit of some sort. [2011 NEC, Article 334.15(B)]
I suppose you can find an inspector in some jurisdictions that might view
things that way, but garages are accepted with Romex every day. A homeowner
having a drill press and a table saw in his garage does not immediately
qualify it as an area under the restrictions you specify.
>
> IMO, even if enclosing it in conduit is not required, given where
> he's putting
> it, I think it's imprudent.
I disagree with that thought Doug. Romex in a wall is very well protected
for 9.999% of the shop work most people here do. Besides - he's already
wired with romex for his outlets and other devices. He's only looking a
lighting runs now, and those would be mostly up in the ceiling, where there
is almost no chance of any damage.
--
-Mike-
[email protected]
Bill wrote:
>
> Yes, there are *lots* of knockouts on the fixture bases. I need to
> check the "wire space" of the fixture bases and of other pertinent
> specifications. If the fixture bases aren't large enough that will
> create mucho extra work.
>
Are you speaking about the flourescent light fixtures, and are you wondering
if they have enough capacity to allow for junctions and pass-throughs? If
so - don't waste your energy. They do.
--
-Mike-
[email protected]
Bill wrote:
>
> I'm not sure adding EMT for the lighting to a shops ceiling, to a shop
> that already has romex in the walls represents an overcomplication.
> I agree if one had PVC conduit, Greenfield, and EMT running across the
> ceiling so that it spelled "b-i-l-l", that it probably wouldn't look
> like the work was completed in a workmanlike manner...
That's not what I was referring to Bill. I was talking about all of the
fuss (if I understood it correctly) with hitting a flush mount box while
also having surface mount boxes right there as well. It seemed to me that
you were trying to make too much of the job by trying to get conduit into
the flush mount.
--
-Mike-
[email protected]
On Tue, 23 Aug 2011 10:27:04 -0400, "Mike Marlow"
<[email protected]> wrote:
>Bill wrote:
>
>>
>> I was thinking in terms of the "wire space" of the box (as in how many
>> wires can be in there, not how much wire can I pack in there). As you
>> know, most/all electrical boxes have their cubic inches written
>> inside. I'll have to get out my chart to do the calculation.
>
>If you feel you must...
Bill is our token _serious_ AR guy here. Of course he must. ;)
But I think the NEC wants him to mess up his ceiling further, with
individual races for each of 3 circuits. I wonder if he'd get dinged
for running the extra 2 through two of the center light fixtures...
--
It is characteristic of all deep human problems that they are
not to be approached without some humor and some bewilderment.
-- Freeman Dyson
Bill wrote:
>
> I was thinking in terms of the "wire space" of the box (as in how many
> wires can be in there, not how much wire can I pack in there). As you
> know, most/all electrical boxes have their cubic inches written
> inside. I'll have to get out my chart to do the calculation.
If you feel you must...
--
-Mike-
[email protected]
You cannot use these fluorescent fixtures for a wire raceway. Only the
wiring necessary for the fixture and other daisy-chained units, downstream,
on the same circuit, can be installed inside.
Don't forget to subtract two wires for each wirenut connection inside,in
your calculations...LOL
------------------
"Bill" wrote in message news:[email protected]...
Not finding the "wire space" of my Lithonia fixture at Lithonia.com, I
took out my ruler: The body of the fixture is 48" x 4" x 1.5" = 288
cubic inches.
This is an over-estimate becuase of the ballast, but it seems fair to
say one can pass a Lot Of Wire (LOW) through this fixture, or a similar
fixture!
Bill
On Tue, 23 Aug 2011 10:27:04 -0400, "Mike Marlow"
<[email protected]> wrote:
>Bill wrote:
>
>>
>> I was thinking in terms of the "wire space" of the box (as in how many
>> wires can be in there, not how much wire can I pack in there). As you
>> know, most/all electrical boxes have their cubic inches written
>> inside. I'll have to get out my chart to do the calculation.
>
>If you feel you must...
Bill is our token _serious_ AR guy here. Of course he must. ;)
But I think the NEC wants him to mess up his ceiling further, with
individual races for each of 3 circuits. I wonder if he'd get dinged
for running the extra 2 through two of the center light fixtures...
--
It is characteristic of all deep human problems that they are
not to be approached without some humor and some bewilderment.
-- Freeman Dyson
Larry Jaques <[email protected]> writes:
>On Mon, 22 Aug 2011 18:47:55 -0400, Bill <[email protected]>
>wrote:
>
>>Larry Jaques wrote:
>>> On Mon, 22 Aug 2011 04:17:46 -0400, Bill<[email protected]>
>>> wrote:
>>>
>>>> Larry Jaques wrote:
>>>>
>>>>> Ceiling box surface mounted with fmt to in-wall box might be my
>>>>> choice. Romex in wall, stapled to stud. http://goo.gl/UYFER
>>>>
>>>>
>>>> You would be using all of the fixtures as "electrical boxes", correct?
>>>>
>>>> So, if I understand your design correctly, I wouldn't need any more
>>>> boxes other than the "switchbox".
>>>
>>> Correctamundo. There are usually lots of knockouts in fluor fixture
>>> bases for connecting EMT fittings. Use those for runs for all three
>>> switches. Check the NEC for congestion. I think 3 pairs will be OK in
>>> 1/2" EMT with a single larger ground, but check.
>>
>>Yes, there are *lots* of knockouts on the fixture bases. I need to
>>check the "wire space" of the fixture bases and of other pertinent
>>specifications. If the fixture bases aren't large enough that will
>>create mucho extra work.
>
>I've never seen a fluor box which didn't have ample space for wiring.
>Mine are for T-12s, so there's room for about 150 extra 14ga THHNs in
>each. ;)
--- Begin Quote ---
Section 410-31 of the NEC (1999 Edition) states:
Fixtures shall not be used as a raceway for circuit conductors.
Exception #1: Fixtures listed for use as a raceway
Exception #2: Fixtures designed for end-to-end assembly to
form a continuous raceway or fixtures connected
together by recognized wiring methods shall be permitted
to carry through conductors of a 2-wire or multiwire
branch circuit supplying the fixtures.
Exception #3: One additional 2-wire branch circuit separately supplying
one or more of the connected fixtures described in exception
#2 shall be permitted to be carried through the fixtures.
Branch-circuit conductors within 3 inches of a ballast within the ballast
compartment shall have an insulation temperature rating not lower than
90 degrees C such as Types RHH, THW, THHN, THHW, FEP, FEPB, SA and XHHW.
--- End Quote ---
Most consumer grade flourescents aren't listed as raceways. That pretty
much leaves exception #2 as the guidance for this application. It also limits
you to 2 two-wire or 1 three-wire and 1 two-wire branch circuits for the
string of fixtures.
Do note the "recognized wiring methods".
Please also be aware that the temperature rating of the conductors being
passed through must be at least 90c (THHN should suffice, but never use NM or NM-B)
scott
Bill <[email protected]> wrote in
news:[email protected]:
> Doug Miller wrote:
>
>> Rigid metallic conduit (RMC) and electrical metallic tubing (EMT) are
>> not the same thing. For your application, you definitely want EMT.
>> Among other things, you can't bend RMC, and you can EMT. RMC is waaay
>> overkill.
>
> That is a nice fact to know about RMC. Thank you.
>
>> I still think that's going to prove to be the easiest route for you
>> (assuming you're still intending to surface-mount all of this).
>
> Yes, I don't doubt you that it would be the easiest way.
> And, I can't argue with your point that "it's just a garage". But
> there is no reason to skimp on this detail. You didnt surface mount
> the wiring in your new wine cellar, did you?
Bill,
Just to add a little info here: You can bend RMC conduit, but it is a
real bitch. For example, because of the increased wall thickness a 3/4"
EMT bender is used to bend 1/2" RMC. As has been mentioned, RMC is way
overkill for a garage.
Steve
m II wrote:
> You cannot use these fluorescent fixtures for a wire raceway. Only the
> wiring necessary for the fixture and other daisy-chained units,
> downstream, on the same circuit, can be installed inside.
> Don't forget to subtract two wires for each wirenut connection
> inside,in your calculations...LOL
>
That is all he is trying to do.
Bill wrote:
> Mike,
>
> Your earlier comments made me think a little more. See if you think
> the following idea makes things easier/better:
>
> I could just bend one piece of EMT to run from the switchbox, up the
> stud, and finish with a 90 degree bend coalescing with the ceiling,
> attaching one those C-type EMT connectors to the end. This eliminates
> the "middle" box in my earlier drawing (so no surface-mount boxes).
>
> What do you think; pretty good, no? There's power in numbers
> (working together)!
>
So, am I understanding that you'd remove the current flush mount box and
install a gang box there and run the conduit up the inside of the wall,
along the stud, and then break through at the ceiling? I'm not sure I have
that right because that would pretty much require you cut out sheetrock in
that stud pocket and then refinish it afterwards - not necessarily the worst
solution though. Just don't know that I'm understanding your plan
correctly.
--
-Mike-
[email protected]
Bill wrote:
> Doug Miller wrote:
>
>> Rigid metallic conduit (RMC) and electrical metallic tubing (EMT)
>> are not the same thing. For your application, you definitely want
>> EMT. Among other things, you can't bend RMC, and you can EMT. RMC is
>> waaay overkill.
>
> That is a nice fact to know about RMC. Thank you.
>
>> I still think that's going to prove to be the easiest route for you
>> (assuming you're still intending to surface-mount all of this).
>
> Yes, I don't doubt you that it would be the easiest way.
> And, I can't argue with your point that "it's just a garage". But
> there is no reason to skimp on this detail. You didnt surface mount
> the wiring in your new wine cellar, did you?
In a residential setting, if you're not going to surface mount, then there's
no reason for EMT - just use Romex. It's perfectly acceptable and equally
good. If you're going to use EMT, then do yourself a favor and look at how
it is done every day by the professionals. Look in commercial structures
the next time you're in one. Notice how they don't overcomplicate and mix
concepts the way you are doing? What you call not skimping on details is
really convoluting a very simple practice.
--
-Mike-
[email protected]
Doug Miller wrote:
>
> I think I misunderstood you, Mike. I took you to be recommending
> using Romex *exposed*, and I don't think that's a good idea here. But
> Romex *in* the wall,
> instead of *on* the wall, is perfectly fine.
Sorry if my wording caused that Doug. I don't even like Romex in exposed
raceways such as floor joists in this kind of environment, if I can avoid
it. I do it, because sometimes you have to, but I prefer not to. I'd
rather secure it to joists and make longer runs, than to just chase through
holes in shops.
--
-Mike-
[email protected]
On Mon, 22 Aug 2011 04:17:46 -0400, Bill <[email protected]>
wrote:
>Larry Jaques wrote:
>
>> Ceiling box surface mounted with fmt to in-wall box might be my
>> choice. Romex in wall, stapled to stud. http://goo.gl/UYFER
>
>
>You would be using all of the fixtures as "electrical boxes", correct?
>
>So, if I understand your design correctly, I wouldn't need any more
>boxes other than the "switchbox".
Correctamundo. There are usually lots of knockouts in fluor fixture
bases for connecting EMT fittings. Use those for runs for all three
switches. Check the NEC for congestion. I think 3 pairs will be OK in
1/2" EMT with a single larger ground, but check.
--
It is characteristic of all deep human problems that they are
not to be approached without some humor and some bewilderment.
-- Freeman Dyson
It would be a little ridiculous to worry about the little protection EMT
provides over Romex when you have surface mounted lighting fixtures exposed
to bashing with lumber. Things need to match and not get ridiculous. Like
Mike says...put Romex in the ceiling and forget all the fuss. A little
surface exposure is not a big deal. If you listened to Dougy you won't be
getting an inspection anyway.
Be sure the Inspector doesn't class your sawdust environment as explosive
(I've seen it blow doors off switches) and you would be running real
conduit....LOL
1--------------------
"Mike Marlow" wrote in message
news:[email protected]...
That's not what I was referring to Bill. I was talking about all of the
fuss (if I understood it correctly) with hitting a flush mount box while
also having surface mount boxes right there as well. It seemed to me that
you were trying to make too much of the job by trying to get conduit into
the flush mount.
2---------------
Bill wrote:
I'm not sure adding EMT for the lighting to a shops ceiling, to a shop
that already has romex in the walls represents an overcomplication.
I agree if one had PVC conduit, Greenfield, and EMT running across the
ceiling so that it spelled "b-i-l-l", that it probably wouldn't look
like the work was completed in a workmanlike manner...
Bill wrote:
>
> Thank you for your interest. Yes, that just what I am prepared to do.
> I've still working with drywall compound anyway, and I haven't primed
> anything yet, so that part is no big deal. The only thing left about
> it that seems unorthodox to me is having the EMT come through the
> wall (6 inches before the ceiling) without some sort of fixture to
> guide it. However, it will be securely clamped to the stud befind the
> wall and to the ceiling after it exits. You could think of it as an
> "all EMT" solution--except part of the EMT lies behind the wall.
That would be a fine solution.
--
-Mike-
[email protected]
Larry Jaques wrote:
> On Sun, 21 Aug 2011 23:50:43 -0400, Bill<[email protected]>
> wrote:
>
>>
>> I put a pdf file on my website which shows my current thinking
>> about making an HTTN run through conduit. Evidentally, Rigid (EMT)
>> is a better choice than Flexible Metal Conduit. BTW, the EMT that is not
>> vertical will be on the ceiling; my SketchUp skills still need more
>> work. Please take a peek:
>>
>> http://web.newsguy.com/MySite/
>>
>> As you can see from my pictures, there are 3 electrical boxes--the
>> switch box mounted behind the wall and the other 2 bexes which are
>> surface mounted. The pictures basically show my current idea. I am left
>> with a question or two (if you would be so kind):
>
> Show your wiring and conduit maps, too, eh?
I did those in pencil several times, except for necessary revisions.
I'll update my SketchUp drawings. The drawings do force one to address
the tough questions!
>
>
>> 1. How is the weight of the vertical piece of EMT supported? It seems
>> that there would be quite a bit of weight on the switch box on the
>> bottom as I don't think the typical clamps that I've seen are designed
>> to prevent the EMT from sliding underneath them. Maybe I need special
>> clamps, extra support for the switch box, or something else?
>
> The nearly-a-pound is taken up by a strap screwed into the stud. ;)
> http://goo.gl/5AQO6 Or switch to stapled romex?
Stapled romex runs to the switchbox and HTTN in EMT runs up (behind the
wall). Running romex after the switchbox may be unthinkable--UNLESS I
color-coded the 3 cables (or use your long FMT solution). It also raises
the wire count in the destination box.
>
>
>> 2. I assume, that to attach the 2nd box (the one on the wall), that the
>> end of the EMT (bent at 90 degrees) is pushed through a hole, connected
>> to the box (with a screw-type connector) and then the box is screwed to
>> the stud through the wall. Please correct me if I am missing anything here.
>
> Ceiling box surface mounted with fmt to in-wall box might be my
> choice. Romex in wall, stapled to stud. http://goo.gl/UYFER
I was thinking along these lines until I read: FMT is not intended to
run farther than about 48", and that EMT was preferred to FMT.
Your idea seems quite acceptable to me... Does the FMT just enter the
wall through a hole in the drywall? That just cannot be right, can it?
White, right???
Bill
Larry Jaques wrote:
> Ceiling box surface mounted with fmt to in-wall box might be my
> choice. Romex in wall, stapled to stud. http://goo.gl/UYFER
You would be using all of the fixtures as "electrical boxes", correct?
So, if I understand your design correctly, I wouldn't need any more
boxes other than the "switchbox".
In article <[email protected]>, Bill <[email protected]> wrote:
>
>I put a pdf file on my website which shows my current thinking
>about making an HTTN
THHN
> run through conduit. Evidentally, Rigid (EMT)
Rigid metallic conduit (RMC) and electrical metallic tubing (EMT) are not the
same thing. For your application, you definitely want EMT. Among other things,
you can't bend RMC, and you can EMT. RMC is waaay overkill.
>is a better choice than Flexible Metal Conduit.
Agreed.
>BTW, the EMT that is not
>vertical will be on the ceiling; my SketchUp skills still need more
>work. Please take a peek:
>
>http://web.newsguy.com/MySite/
>
>As you can see from my pictures, there are 3 electrical boxes--the
>switch box mounted behind the wall and the other 2 bexes which are
>surface mounted. The pictures basically show my current idea. I am left
>with a question or two (if you would be so kind):
>
>
>1. How is the weight of the vertical piece of EMT supported? It seems
>that there would be quite a bit of weight on the switch box on the
>bottom as I don't think the typical clamps that I've seen are designed
>to prevent the EMT from sliding underneath them. Maybe I need special
>clamps, extra support for the switch box, or something else?
Just secure it to the wall in a couple of places. It really doesn't weigh all
that much, not enough that you need to worry about it.
>
>2. I assume, that to attach the 2nd box (the one on the wall), that the
>end of the EMT (bent at 90 degrees) is pushed through a hole, connected
>to the box (with a screw-type connector) and then the box is screwed to
>the stud through the wall. Please correct me if I am missing anything here.
Depends on what type of box you're using.
>
>At least I came up with a way to avoid working at the top-plate near the
>eave (which I could not figure out how to deal with)!!! Thank you for
>your patience!
>
>Bill
>
>P.S. Doug taught me a little about LL (and LB,LR) conduit body
>connectors. These do not seem to make sense here unless you're want to
>run the wire before you finish the drywall. No one would use one of
>those in this model, would they?
I still think that's going to prove to be the easiest route for you (assuming
you're still intending to surface-mount all of this).
Mike Marlow wrote:
> Bill wrote:
>> I put a pdf file on my website which shows my current thinking
>> about making an HTTN run through conduit. Evidentally, Rigid (EMT)
>> is a better choice than Flexible Metal Conduit. BTW, the EMT that is
>> not vertical will be on the ceiling; my SketchUp skills still need
>> more work. Please take a peek:
>
> THHN - Not HTTN...
Mike, Thank you for your good comments (and for correcting my spelling)!
As of this moment, I'm planning to go with LarryJ's suggestion of
running FMT to the switchbox, though things like this can change like
the weather. I haven't read the other messages in this thread yet.
Bill
>
>>
>> http://web.newsguy.com/MySite/
>>
>> As you can see from my pictures, there are 3 electrical boxes--the
>> switch box mounted behind the wall and the other 2 bexes which are
>> surface mounted. The pictures basically show my current idea. I am
>> left with a question or two (if you would be so kind):
>
> So am I - why one flush box and two surface mounted boxes? If you're going
> to run EMT, it's much easier to run it all surface mount. You can get
> extensions to bring your existing flush mount box out so that it's the same
> as your surface mounts if that's the issue.
>
>
>>
>>
>> 1. How is the weight of the vertical piece of EMT supported? It seems
>> that there would be quite a bit of weight on the switch box on the
>> bottom as I don't think the typical clamps that I've seen are designed
>> to prevent the EMT from sliding underneath them. Maybe I need special
>> clamps, extra support for the switch box, or something else?
>
> The box supports the vertical run. If the box is properly installed, it
> will have no trouble supporting the riser.
>
> You should spend some time doing google searches on bending EMT. There's
> quite a bit of good You Tube material out there and you'll want to view it.
> Make sure you understand how to properly measure for bends using the
> indicators on your bender, and make sure you get a good handle on bending
> offsets - you'll be bending quite of few of them.
>
Scott Lurndal wrote:
> Bill<[email protected]> writes:
>>
>> I put a pdf file on my website which shows my current thinking
>> about making an HTTN run through conduit. Evidentally, Rigid (EMT)
>
> EMT and Rigid conduit are two different things. EMT uses setscrew or
> compression fittings, while rigid conduit is threaded and uses threaded
> fittings.
I didn't know that. Thank you!
>
>> 1. How is the weight of the vertical piece of EMT supported? It seems
>> that there would be quite a bit of weight on the switch box on the
>> bottom as I don't think the typical clamps that I've seen are designed
>> to prevent the EMT from sliding underneath them. Maybe I need special
>> clamps, extra support for the switch box, or something else?
>
> Use EMT conduit clamps of the appropriate size. Check the NEC for
> the appropriate spacing (iirc, 3' from junction box, and every 6').
>
> Or use unistrut and unistrut conduit clamps.
>
>>
>> 2. I assume, that to attach the 2nd box (the one on the wall), that the
>> end of the EMT (bent at 90 degrees) is pushed through a hole, connected
>> to the box (with a screw-type connector) and then the box is screwed to
>> the stud through the wall. Please correct me if I am missing anything here.
>
> Either bend an offset in the emt (requires skill), or buy an offset
> setscrew connector to connect the box to the conduit (unless you're
> using the unistrut solution).
>
> scott
Doug Miller wrote:
> Rigid metallic conduit (RMC) and electrical metallic tubing (EMT) are not the
> same thing. For your application, you definitely want EMT. Among other things,
> you can't bend RMC, and you can EMT. RMC is waaay overkill.
That is a nice fact to know about RMC. Thank you.
> I still think that's going to prove to be the easiest route for you (assuming
> you're still intending to surface-mount all of this).
Yes, I don't doubt you that it would be the easiest way.
And, I can't argue with your point that "it's just a garage". But there
is no reason to skimp on this detail. You didnt surface mount the
wiring in your new wine cellar, did you?
In article <[email protected]>, "Mike Marlow" <[email protected]> wrote:
>In a residential setting, if you're not going to surface mount, then there's
>no reason for EMT - just use Romex. It's perfectly acceptable and equally
>good.
Sorry, Mike, I can't agree with you there. This is going in a combination
garage/shop, where an electrical inspector would probably consider the cable
to be subject to physical damage, thus requiring that it be installed in
conduit of some sort. [2011 NEC, Article 334.15(B)]
IMO, even if enclosing it in conduit is not required, given where he's putting
it, I think it's imprudent.
In article <[email protected]>, Bill <[email protected]>
wrote:
>Doug Miller wrote:
>
>> Rigid metallic conduit (RMC) and electrical metallic tubing (EMT) are not the
>> same thing. For your application, you definitely want EMT. Among other
> things,
>> you can't bend RMC, and you can EMT. RMC is waaay overkill.
>
>That is a nice fact to know about RMC. Thank you.
>
>> I still think that's going to prove to be the easiest route for you (assuming
>> you're still intending to surface-mount all of this).
>
>Yes, I don't doubt you that it would be the easiest way.
>And, I can't argue with your point that "it's just a garage". But there
>is no reason to skimp on this detail.
There's also no reason (IMHO) to go to great lengths to conceal wiring in
utility areas such as garages and workshops.
>You didnt surface mount the
>wiring in your new wine cellar, did you?
Nope. But I did surface-mount nearly all of the wiring that I added to my
workshop. Only the new walls got concealed wiring and flush-mounted switches
and receptacles. And what little new wiring I've added in my garage has *all*
been surface-mounted. On the other hand, new wiring in my kitchen is entirely
concealed.
My decision tree looks like this:
Is the wall new construction?
Yes -- use concealed wiring and flush-mounted boxes.
No -- Would concealed wiring and flush-mounted boxes be easy to install?
Yes -- do it.
No -- Would surface-mounted conduit and boxes look out of place?
Yes -- use concealed wiring and flush-mounted boxes.
No -- surface-mount everything.
Wine cellar: Yes. Stop there. Concealed.
Workshop (old walls): No, No, No. Surface mount.
Workshop (new walls): Yes. Stop there. Concealed.
Garage: No, No, No. Surface mount.
Kitchen: No, No, Yes. Concealed.
Larry Jaques wrote:
> On Mon, 22 Aug 2011 04:17:46 -0400, Bill<[email protected]>
> wrote:
>
>> Larry Jaques wrote:
>>
>>> Ceiling box surface mounted with fmt to in-wall box might be my
>>> choice. Romex in wall, stapled to stud. http://goo.gl/UYFER
>>
>>
>> You would be using all of the fixtures as "electrical boxes", correct?
>>
>> So, if I understand your design correctly, I wouldn't need any more
>> boxes other than the "switchbox".
>
> Correctamundo. There are usually lots of knockouts in fluor fixture
> bases for connecting EMT fittings. Use those for runs for all three
> switches. Check the NEC for congestion. I think 3 pairs will be OK in
> 1/2" EMT with a single larger ground, but check.
Yes, there are *lots* of knockouts on the fixture bases. I need to
check the "wire space" of the fixture bases and of other pertinent
specifications. If the fixture bases aren't large enough that will
create mucho extra work.
>
> --
> It is characteristic of all deep human problems that they are
> not to be approached without some humor and some bewilderment.
> -- Freeman Dyson
Mike Marlow wrote:
> Bill wrote:
>> Doug Miller wrote:
>>
>>> Rigid metallic conduit (RMC) and electrical metallic tubing (EMT)
>>> are not the same thing. For your application, you definitely want
>>> EMT. Among other things, you can't bend RMC, and you can EMT. RMC is
>>> waaay overkill.
>>
>> That is a nice fact to know about RMC. Thank you.
>>
>>> I still think that's going to prove to be the easiest route for you
>>> (assuming you're still intending to surface-mount all of this).
>>
>> Yes, I don't doubt you that it would be the easiest way.
>> And, I can't argue with your point that "it's just a garage". But
>> there is no reason to skimp on this detail. You didnt surface mount
>> the wiring in your new wine cellar, did you?
>
> In a residential setting, if you're not going to surface mount, then there's
> no reason for EMT - just use Romex. It's perfectly acceptable and equally
> good. If you're going to use EMT, then do yourself a favor and look at how
> it is done every day by the professionals. Look in commercial structures
> the next time you're in one. Notice how they don't overcomplicate and mix
> concepts the way you are doing? What you call not skimping on details is
> really convoluting a very simple practice.
>
I'm not sure adding EMT for the lighting to a shops ceiling, to a shop
that already has romex in the walls represents an overcomplication.
I agree if one had PVC conduit, Greenfield, and EMT running across the
ceiling so that it spelled "b-i-l-l", that it probably wouldn't look
like the work was completed in a workmanlike manner...
All of the trades people who show up at my house take things as they
find them. None have said, "Let me redo this so it matches..." I have
heard (last week), "Let me save you some money..."
I do respect uniformity, and you'll see it inherent in my design decisions.
Regards,
Bill
Doug Miller wrote:
>> You didnt surface mount the
>> wiring in your new wine cellar, did you?
>
> Nope. But I did surface-mount nearly all of the wiring that I added to my
> workshop. Only the new walls got concealed wiring and flush-mounted switches
> and receptacles. And what little new wiring I've added in my garage has *all*
> been surface-mounted. On the other hand, new wiring in my kitchen is entirely
> concealed.
>
> My decision tree looks like this:
>
> Is the wall new construction?
> Yes -- use concealed wiring and flush-mounted boxes.
> No -- Would concealed wiring and flush-mounted boxes be easy to install?
> Yes -- do it.
> No -- Would surface-mounted conduit and boxes look out of place?
> Yes -- use concealed wiring and flush-mounted boxes.
> No -- surface-mount everything.
>
> Wine cellar: Yes. Stop there. Concealed.
> Workshop (old walls): No, No, No. Surface mount.
> Workshop (new walls): Yes. Stop there. Concealed.
> Garage: No, No, No. Surface mount.
> Kitchen: No, No, Yes. Concealed.
Your decision tree makes a lot of sense.
Artistic endeavers that people do out of passion (like boat-building,
for instance), don't have to make sense. They are, perhaps, just an
outlet for expression. One man's Red Rock plane is another man's
door-stop...
Regards,
Bill
Bill wrote:
> Doug Miller wrote:
>
>>> You didnt surface mount the
>>> wiring in your new wine cellar, did you?
>>
>> Nope. But I did surface-mount nearly all of the wiring that I added to my
>> workshop. Only the new walls got concealed wiring and flush-mounted
>> switches
>> and receptacles. And what little new wiring I've added in my garage
>> has *all*
>> been surface-mounted. On the other hand, new wiring in my kitchen is
>> entirely
>> concealed.
>>
>> My decision tree looks like this:
>>
>> Is the wall new construction?
>> Yes -- use concealed wiring and flush-mounted boxes.
>> No -- Would concealed wiring and flush-mounted boxes be easy to install?
>> Yes -- do it.
>> No -- Would surface-mounted conduit and boxes look out of place?
>> Yes -- use concealed wiring and flush-mounted boxes.
>> No -- surface-mount everything.
>>
>> Wine cellar: Yes. Stop there. Concealed.
>> Workshop (old walls): No, No, No. Surface mount.
>> Workshop (new walls): Yes. Stop there. Concealed.
>> Garage: No, No, No. Surface mount.
>> Kitchen: No, No, Yes. Concealed.
>
> Your decision tree makes a lot of sense.
> Artistic endeavers that people do out of passion (like boat-building,
> for instance), don't have to make sense. They are, perhaps, just an
> outlet for expression. One man's Red Rock plane is another man's
> door-stop...
Oops: That should be Bed Rock plane.... Thought it's not too terrible
of an expression for a rusty one. ; )
>
> Regards,
> Bill
>
>
>
>
Bill wrote:
> Bill wrote:
>> Doug Miller wrote:
>>
>>>> You didnt surface mount the
>>>> wiring in your new wine cellar, did you?
>>>
>>> Nope. But I did surface-mount nearly all of the wiring that I added
>>> to my
>>> workshop. Only the new walls got concealed wiring and flush-mounted
>>> switches
>>> and receptacles. And what little new wiring I've added in my garage
>>> has *all*
>>> been surface-mounted. On the other hand, new wiring in my kitchen is
>>> entirely
>>> concealed.
>>>
>>> My decision tree looks like this:
>>>
>>> Is the wall new construction?
>>> Yes -- use concealed wiring and flush-mounted boxes.
>>> No -- Would concealed wiring and flush-mounted boxes be easy to install?
>>> Yes -- do it.
>>> No -- Would surface-mounted conduit and boxes look out of place?
>>> Yes -- use concealed wiring and flush-mounted boxes.
>>> No -- surface-mount everything.
>>>
>>> Wine cellar: Yes. Stop there. Concealed.
>>> Workshop (old walls): No, No, No. Surface mount.
>>> Workshop (new walls): Yes. Stop there. Concealed.
>>> Garage: No, No, No. Surface mount.
>>> Kitchen: No, No, Yes. Concealed.
>>
>> Your decision tree makes a lot of sense.
>> Artistic endeavers that people do out of passion (like boat-building,
>> for instance), don't have to make sense. They are, perhaps, just an
>> outlet for expression. One man's Bed Rock plane is another man's
>> door-stop...
I'm in favor of removing the word "just" above.
>
>>
>> Regards,
>> Bill
>>
>>
>>
>>
>
Larry Jaques wrote:
> On Mon, 22 Aug 2011 18:47:55 -0400, Bill<[email protected]>
> wrote:
>
>> Larry Jaques wrote:
>>> On Mon, 22 Aug 2011 04:17:46 -0400, Bill<[email protected]>
>>> wrote:
>>>
>>>> Larry Jaques wrote:
>>>>
>>>>> Ceiling box surface mounted with fmt to in-wall box might be my
>>>>> choice. Romex in wall, stapled to stud. http://goo.gl/UYFER
>>>>
>>>>
>>>> You would be using all of the fixtures as "electrical boxes", correct?
>>>>
>>>> So, if I understand your design correctly, I wouldn't need any more
>>>> boxes other than the "switchbox".
>>>
>>> Correctamundo. There are usually lots of knockouts in fluor fixture
>>> bases for connecting EMT fittings. Use those for runs for all three
>>> switches. Check the NEC for congestion. I think 3 pairs will be OK in
>>> 1/2" EMT with a single larger ground, but check.
>>
>> Yes, there are *lots* of knockouts on the fixture bases. I need to
>> check the "wire space" of the fixture bases and of other pertinent
>> specifications. If the fixture bases aren't large enough that will
>> create mucho extra work.
>
> I've never seen a fluor box which didn't have ample space for wiring.
> Mine are for T-12s, so there's room for about 150 extra 14ga THHNs in
> each. ;)
>
> Even in the little T-5 HO boxes, there's probably enough room for a
> dozen extra wires. The further addition of half a dozen extra
> wirenuts is doubtful, though.
I was thinking in terms of the "wire space" of the box (as in how many
wires can be in there, not how much wire can I pack in there). As you
know, most/all electrical boxes have their cubic inches written inside.
I'll have to get out my chart to do the calculation.
Bill wrote:
>>> Yes, there are *lots* of knockouts on the fixture bases. I need to
>>> check the "wire space" of the fixture bases and of other pertinent
>>> specifications. If the fixture bases aren't large enough that will
>>> create mucho extra work.
>>
Larry Jaques wrote:
>> I've never seen a fluor box which didn't have ample space for wiring.
>> Mine are for T-12s, so there's room for about 150 extra 14ga THHNs in
>> each. ;)
>>
>> Even in the little T-5 HO boxes, there's probably enough room for a
>> dozen extra wires. The further addition of half a dozen extra
>> wirenuts is doubtful, though.
>
> I was thinking in terms of the "wire space" of the box (as in how many
> wires can be in there, not how much wire can I pack in there). As you
> know, most/all electrical boxes have their cubic inches written inside.
> I'll have to get out my chart to do the calculation.
Not finding the "wire space" of my Lithonia fixture at Lithonia.com, I
took out my ruler: The body of the fixture is 48" x 4" x 1.5" = 288
cubic inches.
This is an over-estimate becuase of the ballast, but it seems fair to
say one can pass a Lot Of Wire (LOW) through this fixture, or a similar
fixture!
Bill
*This is neither an offer to sell nor a solicitation of an offer to buy
the light fixtures described above. An offering is made only by the
prospectus. The sales and advertising literature, and in particular the
LOW numbers, must be read in conjunction with the prospectus in order
to fully understand all of the implications and risks of the fixtures to
which the prospectus relates.
A copy of the prospectus must be made available to you in
connection with any sale. No sale is made except by a prospectus filed
with the Department of Law of the State of New York. Neither Home Depot,
the Attorney-General of the State of New York nor any other state
commissions has approved or disapproved of these
fixtures or determined if the corresponding prospectus is truthful or
complete. Any representation to the contrary is a criminal offense. (!)
On 8/23/2011 9:05 AM, m II wrote:
> You cannot use these fluorescent fixtures for a wire raceway. Only the
> wiring necessary for the fixture and other daisy-chained units,
> downstream, on the same circuit, can be installed inside.
That's all he's *planning* to put in there -- what made you think otherwise?
In article <[email protected]>, "Mike Marlow" <[email protected]> wrote:
>Doug Miller wrote:
>> In article <[email protected]>, "Mike Marlow"
>> <[email protected]> wrote:
>>
>>> In a residential setting, if you're not going to surface mount, then
>>> there's no reason for EMT - just use Romex. It's perfectly
>>> acceptable and equally good.
>>
>> Sorry, Mike, I can't agree with you there. This is going in a combination
>> garage/shop, where an electrical inspector would probably consider the cable
>> to be subject to physical damage, thus requiring that it be installed in
>> conduit of some sort. [2011 NEC, Article 334.15(B)]
>
>I suppose you can find an inspector in some jurisdictions that might view
>things that way, but garages are accepted with Romex every day. A homeowner
>having a drill press and a table saw in his garage does not immediately
>qualify it as an area under the restrictions you specify.
>
>>
>> IMO, even if enclosing it in conduit is not required, given where
>> he's putting
>> it, I think it's imprudent.
>
>I disagree with that thought Doug. Romex in a wall is very well protected
>for 9.999% of the shop work most people here do.
I think I misunderstood you, Mike. I took you to be recommending using Romex
*exposed*, and I don't think that's a good idea here. But Romex *in* the wall,
instead of *on* the wall, is perfectly fine.
On 8/23/2011 11:02 AM, m II wrote:
> It would be a little ridiculous to worry about the little protection EMT
> provides over Romex when you have surface mounted lighting fixtures
> exposed to bashing with lumber. Things need to match and not get
> ridiculous. Like Mike says...put Romex in the ceiling and forget all the
> fuss. A little surface exposure is not a big deal. If you listened to
> Dougy you won't be getting an inspection anyway.
What on earth are you talking about? I never recommended omitting an
inspection.
Scott Lurndal wrote:
> --- Begin Quote ---
>
> Section 410-31 of the NEC (1999 Edition) states:
>
> Fixtures shall not be used as a raceway for circuit conductors.
>
> Exception #1: Fixtures listed for use as a raceway
> Exception #2: Fixtures designed for end-to-end assembly to
> form a continuous raceway or fixtures connected
> together by recognized wiring methods shall be permitted
> to carry through conductors of a 2-wire or multiwire
> branch circuit supplying the fixtures.
> Exception #3: One additional 2-wire branch circuit separately supplying
> one or more of the connected fixtures described in exception
> #2 shall be permitted to be carried through the fixtures.
>
> Branch-circuit conductors within 3 inches of a ballast within the ballast
> compartment shall have an insulation temperature rating not lower than
> 90 degrees C such as Types RHH, THW, THHN, THHW, FEP, FEPB, SA and XHHW.
>
> --- End Quote ---
>
> Most consumer grade flourescents aren't listed as raceways. That pretty
> much leaves exception #2 as the guidance for this application. It also limits
> you to 2 two-wire or 1 three-wire and 1 two-wire branch circuits for the
> string of fixtures.
>
Scott.
There is only 1 15A branch circuit. However, I had planned for it to
"split" through 3 switches in the switchbox and pass the resultant 5
wires--3 hot, 1 neutral, 1 ground, through the fixtures as necessary to
power them. If I understand correctly, this would qualify as a single
2-wire branch circuit, wouldn't it?
TYVM!
Bill
> Do note the "recognized wiring methods".
>
> Please also be aware that the temperature rating of the conductors being
> passed through must be at least 90c (THHN should suffice, but never use NM or NM-B)
>
> scott
Mike Marlow wrote:
> That's not what I was referring to Bill. I was talking about all of the
> fuss (if I understood it correctly) with hitting a flush mount box while
> also having surface mount boxes right there as well. It seemed to me that
> you were trying to make too much of the job by trying to get conduit into
> the flush mount.
>
>
Mike,
Your earlier comments made me think a little more. See if you think the
following idea makes things easier/better:
I could just bend one piece of EMT to run from the switchbox, up the
stud, and finish with a 90 degree bend coalescing with the ceiling,
attaching one those C-type EMT connectors to the end. This eliminates
the "middle" box in my earlier drawing (so no surface-mount boxes).
What do you think; pretty good, no? There's power in numbers (working
together)!
Bill
In article <[email protected]>, Bill <[email protected]> wrote:
>Scott Lurndal wrote:
>
>> --- Begin Quote ---
>>
>> Section 410-31 of the NEC (1999 Edition) states:
>>
>> Fixtures shall not be used as a raceway for circuit conductors.
>>
>> Exception #1: Fixtures listed for use as a raceway
>> Exception #2: Fixtures designed for end-to-end assembly to
>> form a continuous raceway or fixtures connected
>> together by recognized wiring methods shall be permitted
>> to carry through conductors of a 2-wire or multiwire
>> branch circuit supplying the fixtures.
>> Exception #3: One additional 2-wire branch circuit separately supplying
>> one or more of the connected fixtures described in
> exception
>> #2 shall be permitted to be carried through the fixtures.
>>
>> Branch-circuit conductors within 3 inches of a ballast within the ballast
>> compartment shall have an insulation temperature rating not lower than
>> 90 degrees C such as Types RHH, THW, THHN, THHW, FEP, FEPB, SA and XHHW.
>>
>> --- End Quote ---
>>
>> Most consumer grade flourescents aren't listed as raceways. That pretty
>> much leaves exception #2 as the guidance for this application. It also
> limits
>> you to 2 two-wire or 1 three-wire and 1 two-wire branch circuits for the
>> string of fixtures.
>>
>
>Scott.
>
>There is only 1 15A branch circuit. However, I had planned for it to
>"split" through 3 switches in the switchbox and pass the resultant 5
>wires--3 hot, 1 neutral, 1 ground, through the fixtures as necessary to
>power them. If I understand correctly, this would qualify as a single
>2-wire branch circuit, wouldn't it?
Absolutely. It's still one circuit, and it's still a "two-wire branch circuit"
despite there being four wires (the ground is not counted) because your three
hots are derived from the same point.
In any event, since the exception permits a multi-wire branch circuit, that
particular point is moot anyway. It's clearly a single circuit: there's only
one single-pole breaker.
>TYVM!
>Bill
>
>
>> Do note the "recognized wiring methods".
Which would include, presumably, being connected by a properly-installed
section of EMT.
>>
>> Please also be aware that the temperature rating of the conductors being
>> passed through must be at least 90c (THHN should suffice, but never use NM or
> NM-B)
>>
>> scott
>
Mike Marlow wrote:
> Bill wrote:
>
>> Mike,
>>
>> Your earlier comments made me think a little more. See if you think
>> the following idea makes things easier/better:
>>
>> I could just bend one piece of EMT to run from the switchbox, up the
>> stud, and finish with a 90 degree bend coalescing with the ceiling,
>> attaching one those C-type EMT connectors to the end. This eliminates
>> the "middle" box in my earlier drawing (so no surface-mount boxes).
>>
>> What do you think; pretty good, no? There's power in numbers
>> (working together)!
>>
>
> So, am I understanding that you'd remove the current flush mount box and
> install a gang box there and run the conduit up the inside of the wall,
> along the stud, and then break through at the ceiling? I'm not sure I have
> that right because that would pretty much require you cut out sheetrock in
> that stud pocket and then refinish it afterwards - not necessarily the worst
> solution though. Just don't know that I'm understanding your plan
> correctly.
Thank you for your interest. Yes, that just what I am prepared to do.
I've still working with drywall compound anyway, and I haven't primed
anything yet, so that part is no big deal. The only thing left about it
that seems unorthodox to me is having the EMT come through the wall (6
inches before the ceiling) without some sort of fixture to guide it.
However, it will be securely clamped to the stud befind the wall and to
the ceiling after it exits. You could think of it as an "all EMT"
solution--except part of the EMT lies behind the wall.
Doug Miller wrote:
> In article<[email protected]>, Bill<[email protected]> wrote:
>> Scott Lurndal wrote:
>>
>>> --- Begin Quote ---
>>>
>>> Section 410-31 of the NEC (1999 Edition) states:
>>>
>>> Fixtures shall not be used as a raceway for circuit conductors.
>>>
>>> Exception #1: Fixtures listed for use as a raceway
>>> Exception #2: Fixtures designed for end-to-end assembly to
>>> form a continuous raceway or fixtures connected
>>> together by recognized wiring methods shall be permitted
>>> to carry through conductors of a 2-wire or multiwire
>>> branch circuit supplying the fixtures.
>>> Exception #3: One additional 2-wire branch circuit separately supplying
>>> one or more of the connected fixtures described in
>> exception
>>> #2 shall be permitted to be carried through the fixtures.
>>>
>>> Branch-circuit conductors within 3 inches of a ballast within the ballast
>>> compartment shall have an insulation temperature rating not lower than
>>> 90 degrees C such as Types RHH, THW, THHN, THHW, FEP, FEPB, SA and XHHW.
>>>
>>> --- End Quote ---
>>>
>>> Most consumer grade flourescents aren't listed as raceways. That pretty
>>> much leaves exception #2 as the guidance for this application. It also
>> limits
>>> you to 2 two-wire or 1 three-wire and 1 two-wire branch circuits for the
>>> string of fixtures.
>>>
>>
>> Scott.
>>
>> There is only 1 15A branch circuit. However, I had planned for it to
>> "split" through 3 switches in the switchbox and pass the resultant 5
>> wires--3 hot, 1 neutral, 1 ground, through the fixtures as necessary to
>> power them. If I understand correctly, this would qualify as a single
>> 2-wire branch circuit, wouldn't it?
>
> Absolutely. It's still one circuit, and it's still a "two-wire branch circuit"
> despite there being four wires (the ground is not counted) because your three
> hots are derived from the same point.
>
> In any event, since the exception permits a multi-wire branch circuit, that
> particular point is moot anyway. It's clearly a single circuit: there's only
> one single-pole breaker.
>
>> TYVM!
>> Bill
Thank you for your confirmation Doug!
>>
>>
>>> Do note the "recognized wiring methods".
>
> Which would include, presumably, being connected by a properly-installed
> section of EMT.
>>>
>>> Please also be aware that the temperature rating of the conductors being
>>> passed through must be at least 90c (THHN should suffice, but never use NM or
>> NM-B)
>>>
>>> scott
>>
Mike Marlow wrote:
> Bill wrote:
>
>>
>> Thank you for your interest. Yes, that just what I am prepared to do.
>> I've still working with drywall compound anyway, and I haven't primed
>> anything yet, so that part is no big deal. The only thing left about
>> it that seems unorthodox to me is having the EMT come through the
>> wall (6 inches before the ceiling) without some sort of fixture to
>> guide it. However, it will be securely clamped to the stud befind the
>> wall and to the ceiling after it exits. You could think of it as an
>> "all EMT" solution--except part of the EMT lies behind the wall.
>
> That would be a fine solution.
>
TYVM, I con't get too many replies to my posts like that! : )
Bill <[email protected]> writes:
>
>I put a pdf file on my website which shows my current thinking
>about making an HTTN run through conduit. Evidentally, Rigid (EMT)
EMT and Rigid conduit are two different things. EMT uses setscrew or
compression fittings, while rigid conduit is threaded and uses threaded
fittings.
>is a better choice than Flexible Metal Conduit. BTW, the EMT that is not
Flexible metal conduit is more often subject to local jurisdictional
restrictions and is not suitable to be used as a grounding conductor.
>1. How is the weight of the vertical piece of EMT supported? It seems
>that there would be quite a bit of weight on the switch box on the
>bottom as I don't think the typical clamps that I've seen are designed
>to prevent the EMT from sliding underneath them. Maybe I need special
>clamps, extra support for the switch box, or something else?
Use EMT conduit clamps of the appropriate size. Check the NEC for
the appropriate spacing (iirc, 3' from junction box, and every 6').
Or use unistrut and unistrut conduit clamps.
>
>2. I assume, that to attach the 2nd box (the one on the wall), that the
>end of the EMT (bent at 90 degrees) is pushed through a hole, connected
>to the box (with a screw-type connector) and then the box is screwed to
>the stud through the wall. Please correct me if I am missing anything here.
Either bend an offset in the emt (requires skill), or buy an offset
setscrew connector to connect the box to the conduit (unless you're
using the unistrut solution).
scott
On Mon, 22 Aug 2011 09:34:03 -0500, Swingman <[email protected]> wrote:
>On 8/22/2011 6:11 AM, Mike Marlow wrote:
>
>> THHN - Not HTTN...
>
>THANK YOU!!
Good catch, guys.
--
It is characteristic of all deep human problems that they are
not to be approached without some humor and some bewilderment.
-- Freeman Dyson
On Mon, 22 Aug 2011 03:47:12 -0400, Bill <[email protected]>
wrote:
>Larry Jaques wrote:
>> On Sun, 21 Aug 2011 23:50:43 -0400, Bill<[email protected]>
>> wrote:
>>
>>>
>>> I put a pdf file on my website which shows my current thinking
>>> about making an HTTN run through conduit. Evidentally, Rigid (EMT)
>>> is a better choice than Flexible Metal Conduit. BTW, the EMT that is not
>>> vertical will be on the ceiling; my SketchUp skills still need more
>>> work. Please take a peek:
>>>
>>> http://web.newsguy.com/MySite/
>>>
>>> As you can see from my pictures, there are 3 electrical boxes--the
>>> switch box mounted behind the wall and the other 2 bexes which are
>>> surface mounted. The pictures basically show my current idea. I am left
>>> with a question or two (if you would be so kind):
>>
>> Show your wiring and conduit maps, too, eh?
>
>I did those in pencil several times, except for necessary revisions.
>I'll update my SketchUp drawings. The drawings do force one to address
>the tough questions!
>
>>
>>
>>> 1. How is the weight of the vertical piece of EMT supported? It seems
>>> that there would be quite a bit of weight on the switch box on the
>>> bottom as I don't think the typical clamps that I've seen are designed
>>> to prevent the EMT from sliding underneath them. Maybe I need special
>>> clamps, extra support for the switch box, or something else?
>>
>> The nearly-a-pound is taken up by a strap screwed into the stud. ;)
>> http://goo.gl/5AQO6 Or switch to stapled romex?
>
>Stapled romex runs to the switchbox and HTTN in EMT runs up (behind the
>wall). Running romex after the switchbox may be unthinkable--UNLESS I
>color-coded the 3 cables (or use your long FMT solution). It also raises
>the wire count in the destination box.
Right, get a deep one or use a duplex box for the room. But it's only
3 pieces of 14/2(grounded) romex and 7 14ga HTTNs (lone larger ground
if OK by the NEC?)
I use very large needle nose pliers with heatshrink on the tips to
bend wiring in breakout boxes, then stuff it so the lid closes without
any problems. It works especially well with the dadgummed 10ga wire.
That stuff might as well be steel, as far as bending it with human
fingers goes. My fingers are like vise grips until it comes to stiff
wire.
>>> 2. I assume, that to attach the 2nd box (the one on the wall), that the
>>> end of the EMT (bent at 90 degrees) is pushed through a hole, connected
>>> to the box (with a screw-type connector) and then the box is screwed to
>>> the stud through the wall. Please correct me if I am missing anything here.
>>
>> Ceiling box surface mounted with fmt to in-wall box might be my
>> choice. Romex in wall, stapled to stud. http://goo.gl/UYFER
>
>I was thinking along these lines until I read: FMT is not intended to
>run farther than about 48", and that EMT was preferred to FMT.
>Your idea seems quite acceptable to me... Does the FMT just enter the
>wall through a hole in the drywall? That just cannot be right, can it?
Ayup, but it plugs into fittings, then into a box. I've seen gray
underground style PVC conduit used by itself, hanging into midair with
wiring coming out. To code? Prolly not. ;) ENT is blue plastic
conduit for use indoors. Time to research it, Bill! <evil grinne>
>White, right???
Walls, ceiling, and floor, yes. FMT/ENT? Up to you, but I thought
you'd want color coordination in your EMT and FMT, so I mentioned
painting the conduit and connectors. But the blue is awfully pretty.
I'd leave it.
--
It is characteristic of all deep human problems that they are
not to be approached without some humor and some bewilderment.
-- Freeman Dyson
On Mon, 22 Aug 2011 18:47:55 -0400, Bill <[email protected]>
wrote:
>Larry Jaques wrote:
>> On Mon, 22 Aug 2011 04:17:46 -0400, Bill<[email protected]>
>> wrote:
>>
>>> Larry Jaques wrote:
>>>
>>>> Ceiling box surface mounted with fmt to in-wall box might be my
>>>> choice. Romex in wall, stapled to stud. http://goo.gl/UYFER
>>>
>>>
>>> You would be using all of the fixtures as "electrical boxes", correct?
>>>
>>> So, if I understand your design correctly, I wouldn't need any more
>>> boxes other than the "switchbox".
>>
>> Correctamundo. There are usually lots of knockouts in fluor fixture
>> bases for connecting EMT fittings. Use those for runs for all three
>> switches. Check the NEC for congestion. I think 3 pairs will be OK in
>> 1/2" EMT with a single larger ground, but check.
>
>Yes, there are *lots* of knockouts on the fixture bases. I need to
>check the "wire space" of the fixture bases and of other pertinent
>specifications. If the fixture bases aren't large enough that will
>create mucho extra work.
I've never seen a fluor box which didn't have ample space for wiring.
Mine are for T-12s, so there's room for about 150 extra 14ga THHNs in
each. ;)
Even in the little T-5 HO boxes, there's probably enough room for a
dozen extra wires. The further addition of half a dozen extra
wirenuts is doubtful, though.
--
It is characteristic of all deep human problems that they are
not to be approached without some humor and some bewilderment.
-- Freeman Dyson
On Sun, 21 Aug 2011 23:50:43 -0400, Bill <[email protected]>
wrote:
>
>I put a pdf file on my website which shows my current thinking
>about making an HTTN run through conduit. Evidentally, Rigid (EMT)
>is a better choice than Flexible Metal Conduit. BTW, the EMT that is not
>vertical will be on the ceiling; my SketchUp skills still need more
>work. Please take a peek:
>
>http://web.newsguy.com/MySite/
>
>As you can see from my pictures, there are 3 electrical boxes--the
>switch box mounted behind the wall and the other 2 bexes which are
>surface mounted. The pictures basically show my current idea. I am left
>with a question or two (if you would be so kind):
Show your wiring and conduit maps, too, eh?
>1. How is the weight of the vertical piece of EMT supported? It seems
>that there would be quite a bit of weight on the switch box on the
>bottom as I don't think the typical clamps that I've seen are designed
>to prevent the EMT from sliding underneath them. Maybe I need special
>clamps, extra support for the switch box, or something else?
The nearly-a-pound is taken up by a strap screwed into the stud. ;)
http://goo.gl/5AQO6 Or switch to stapled romex?
>2. I assume, that to attach the 2nd box (the one on the wall), that the
>end of the EMT (bent at 90 degrees) is pushed through a hole, connected
>to the box (with a screw-type connector) and then the box is screwed to
>the stud through the wall. Please correct me if I am missing anything here.
Ceiling box surface mounted with fmt to in-wall box might be my
choice. Romex in wall, stapled to stud. http://goo.gl/UYFER
>At least I came up with a way to avoid working at the top-plate near the
>eave (which I could not figure out how to deal with)!!! Thank you for
>your patience!
>
>P.S. Doug taught me a little about LL (and LB,LR) conduit body
>connectors. These do not seem to make sense here unless you're want to
>run the wire before you finish the drywall. No one would use one of
>those in this model, would they?
http://goo.gl/mKpvn
--
It is characteristic of all deep human problems that they are
not to be approached without some humor and some bewilderment.
-- Freeman Dyson