Protecting wiring in walls
 

I know about the plates that one installs onto a stud where wiring
passes through it, but that is possible only on the side that is not yet
finished. What about the other side, the already-finished side? My
brother-in-law says that in Canada they use metal sleeves through the
studs, and the wiring then goes through the sleeve and is protected from
both sides. When I've asked here in the US, people say it sounds like a
great idea but they've never seen such a thing.

Are these available, and if so where?

--
MB

Whether you vote Democrat or Republican in November, the country will
still be run from boardrooms in the USA and elsewhere, not by your
elected representatives.

In the US, code says you don't need a metal plate unless the wire is less
than 1 1/4 inches from the edge of the stud. There are no circumstances in a
regular 2x4 wall that would require a plate on both sides. Most of the time
you don't need one at all, if you drill your hole in the middle of the stud.
Usually people use these when you have to notch to run the wire near the
edge for some reason.

"Minnie Bannister" wrote in message
...
I know about the plates that one installs onto a stud where wiring
passes through it, but that is possible only on the side that is not yet
finished. What about the other side, the already-finished side? My
brother-in-law says that in Canada they use metal sleeves through the
studs, and the wiring then goes through the sleeve and is protected from
both sides. When I've asked here in the US, people say it sounds like a
great idea but they've never seen such a thing.

Are these available, and if so where?

Minnie Bannister wrote:
I know about the plates that one installs onto a stud where wiring
passes through it, but that is possible only on the side that is not yet
finished. What about the other side, the already-finished side? My
brother-in-law says that in Canada they use metal sleeves through the
studs, and the wiring then goes through the sleeve and is protected from
both sides. When I've asked here in the US, people say it sounds like a
great idea but they've never seen such a thing.

Are these available, and if so where?


If the holes are drilled at least 1&1/4" from the face of the stud on
both sides then there is little likelihood of damage to the cable.
Drywall screws are 1&1/4" long so even if over driven clean through the
drywall they cannot reach a hole that is at least that far from the face
of the stud. 3/4" holes that are drilled in the center of the stud
should work fine.
--
Tom H

So people never drive screws or nails longer than 1 1/4" long into a
wall? I certainly have.

--
MB

Whether you vote Democrat or Republican in November, the country will
still be run from boardrooms in the USA and elsewhere, not by your
elected representatives.


On 10/11/04 11:10 am J T put fingers to keyboard and launched the
following message into cyberspace:

In the US, code says you don't need a metal plate unless the wire is less
than 1 1/4 inches from the edge of the stud. There are no circumstances in a
regular 2x4 wall that would require a plate on both sides. Most of the time
you don't need one at all, if you drill your hole in the middle of the stud.
Usually people use these when you have to notch to run the wire near the
edge for some reason.

I know about the plates that one installs onto a stud where wiring
passes through it, but that is possible only on the side that is not yet
finished. What about the other side, the already-finished side? My
brother-in-law says that in Canada they use metal sleeves through the
studs, and the wiring then goes through the sleeve and is protected from
both sides. When I've asked here in the US, people say it sounds like a
great idea but they've never seen such a thing.

Are these available, and if so where?

Here in Canada, I have never seen such a thing as a metal sleeve to fit
studs. Where is he located and where has he seen such things being used?

"Minnie Bannister" wrote in message
...
I know about the plates that one installs onto a stud where wiring
passes through it, but that is possible only on the side that is not yet
finished. What about the other side, the already-finished side? My
brother-in-law says that in Canada they use metal sleeves through the
studs, and the wiring then goes through the sleeve and is protected from
both sides. When I've asked here in the US, people say it sounds like a
great idea but they've never seen such a thing.

Are these available, and if so where?

--
MB

Whether you vote Democrat or Republican in November, the country will
still be run from boardrooms in the USA and elsewhere, not by your
elected representatives.

There's also at least 3/8" of drywall between you and that wire... and
chances are the wire is really more like 1.5-1.75" from the edge if it's in
the middle. So you're talking a minimum of 1 5/8" and probably over 2".

This is the code... it's how every house in the U.S. is built. I wouldn't
get in the habit of pounding 3" framing nails into finished walls. You'd
probably go through any wire protection with that anyway.

"Minnie Bannister" wrote in message
...
So people never drive screws or nails longer than 1 1/4" long into a
wall? I certainly have.

--
MB

Whether you vote Democrat or Republican in November, the country will
still be run from boardrooms in the USA and elsewhere, not by your
elected representatives.


On 10/11/04 11:10 am J T put fingers to keyboard and launched the
following message into cyberspace:

In the US, code says you don't need a metal plate unless the wire is
less
than 1 1/4 inches from the edge of the stud. There are no circumstances
in a
regular 2x4 wall that would require a plate on both sides. Most of the
time
you don't need one at all, if you drill your hole in the middle of the
stud.
Usually people use these when you have to notch to run the wire near the
edge for some reason.

I know about the plates that one installs onto a stud where wiring
passes through it, but that is possible only on the side that is not yet
finished. What about the other side, the already-finished side? My
brother-in-law says that in Canada they use metal sleeves through the
studs, and the wiring then goes through the sleeve and is protected from
both sides. When I've asked here in the US, people say it sounds like a
great idea but they've never seen such a thing.

Are these available, and if so where?

He's in Woodstock, Ontario, and I saw him using them in a partition wall
he was building in his basement. Where he saw them being used I have no
idea -- perhaps when his new condo was still under construction.

--
MB

Whether you vote Democrat or Republican in November, the country will
still be run from boardrooms in the USA and elsewhere, not by your
elected representatives.


On 10/11/04 11:43 am Eric Tonks put fingers to keyboard and launched the
following message into cyberspace:

Here in Canada, I have never seen such a thing as a metal sleeve to fit
studs. Where is he located and where has he seen such things being used?

I know about the plates that one installs onto a stud where wiring
passes through it, but that is possible only on the side that is not yet
finished. What about the other side, the already-finished side? My
brother-in-law says that in Canada they use metal sleeves through the
studs, and the wiring then goes through the sleeve and is protected from
both sides. When I've asked here in the US, people say it sounds like a
great idea but they've never seen such a thing.

Are these available, and if so where?

Way back in the 20th century before the Florida Unified Building Code most
local AHJs wanted to see cables sleeved in EMT if the 1.25" could not be
maintained in any dimension. Now they are OK if the cable is secured 1.25"
horizontally from the furring strip, even if the void (to the block) is only
3/4" deep. It is fairly unlikely that a sheetrock installer will miss by that
far but a homeowner will just start driving nails when they hang pictures and
such.

But he lived in BC previously. Perhaps he saw them used there.

--
MB

Whether you vote Democrat or Republican in November, the country will
still be run from boardrooms in the USA and elsewhere, not by your
elected representatives.


I wrote:

He's in Woodstock, Ontario, and I saw him using them in a partition wall
he was building in his basement. Where he saw them being used I have no
idea -- perhaps when his new condo was still under construction.

On Mon, 11 Oct 2004 08:28:22 -0700, Minnie Bannister wrote
(in article ):

So people never drive screws or nails longer than 1 1/4" long into a
wall? I certainly have.



The code is concerned with protecting the wiring from sheetrock screws. As
other posters have observed, a standard 1-5/8" drywall screw driven through
1/2" drywall and indented 1/8" will penetrate the stud 1". There is no
reqirement to protect NM cable (or AC or MC for that matter) from every
eventality, such as someone hanging a heavy wall-shelf or similar with 3-1/2"
screws. It's just common sense to check for hidden electrical or plumbing
when using long fasteners. You can't be expected to take that precaution
when hanging sheetrock, due to the number of screws involved.

If you expect the wiring is going to be subject to damage, the code requires
that it be protected in an EMT or similar sleeve. For example, if you knew
that a set of shelving was going to be hung right over the wiring run this
precaution would make sense.

I suppose you could use 1-1/2" long sections of 3/4" or 1/2" EMT press-fit
into the holes in the studs, but I have never done this. It seems an
unnecessary amount of work. Where damage to concealed NM was a concern, I
have sleeved it in EMT or steel flex.

I would even go so far as to say running NM through sections of EMT could
increase the overall risk because of the potential for damaging the wire
during installation. You'd probably have to flare the ends of each section
in order to safely pull NM through a run of several studs, because otherwise
you'd risk gouging the cable as you pulled it through the sharp edges of the
EMT pieces. It would be a lot of work to do it properly, probably much
easier/cheaper to just use MC instead.

And, you'd probably be violating code if you used 1/2" EMT technically,
since you can't legally install 12/2 (and probably not even 14/2) in 1/2"
EMT due to fill limits.

Anyway your basic point is the same.. the code can't protect against
everything. There is a balance between reasonable precautions, common sense,
and cost of installation.

"KJS" wrote in message
obal.net...
I suppose you could use 1-1/2" long sections of 3/4" or 1/2" EMT press-fit
into the holes in the studs, but I have never done this. It seems an
unnecessary amount of work. Where damage to concealed NM was a concern, I
have sleeved it in EMT or steel flex.

On 2004-10-11, J T wrote:

And, you'd probably be violating code if you used 1/2" EMT technically,
since you can't legally install 12/2 (and probably not even 14/2) in 1/2"
EMT due to fill limits.

Actually, I don't believe this is true. With a single cable, the NEC
allows 53% conduit fill, and 1/2" EMT has an interior diameter of
about 5/8". This yields 0.161 in^2 of usable area. The 12/2 NMB
cable sample I measured is 0.39" x 0.18", and it has to be treated as
a circle of diameter 0.39". This yields a cross-sectional area of
0.119 in^2, which is less than 0.161 in^2. BTW, my sample of 12/3 NMB
cable has a diameter of 0.37", so a single 12/3 NMB cable is OK too.
I don't have a sample of 12/4 here.

Cheers,
Wayne

Interesting... I was guessing 12/2 was 1/2 inch wide. Long ago I did once
try to pull a 12/2 through a 1/2" EMT and while it can be done, that stuff
is very, very difficult to get around any sort of bend in a tube that tight.
Even if it is allowed you'd be hard pressed to have a good reason to go to
that kind of trouble, far easier to use single conductors. I imagine 12/3 is
even tougher.

"Wayne Whitney" wrote in message
...
On 2004-10-11, J T wrote:

And, you'd probably be violating code if you used 1/2" EMT technically,
since you can't legally install 12/2 (and probably not even 14/2) in
1/2"
EMT due to fill limits.

Actually, I don't believe this is true. With a single cable, the NEC
allows 53% conduit fill, and 1/2" EMT has an interior diameter of
about 5/8". This yields 0.161 in^2 of usable area. The 12/2 NMB
cable sample I measured is 0.39" x 0.18", and it has to be treated as
a circle of diameter 0.39". This yields a cross-sectional area of
0.119 in^2, which is less than 0.161 in^2. BTW, my sample of 12/3 NMB
cable has a diameter of 0.37", so a single 12/3 NMB cable is OK too.
I don't have a sample of 12/4 here.

Cheers,
Wayne

Long ago I did once
try to pull a 12/2 through a 1/2" EMT and while it can be done...

Newer NM-b is smaller than the old TW NM but whenever I have seen EMT sleeves
the run was a single straight section with no bends so it is pretty easy to do.
You do have to ream the burrs off the EMT to avoid damage but you should really
be using a Romex to EMT connector on the end.

Right... of course I still wonder what kind of situation lends itself to a
half-EMT, half-exposed romex installation between boxes? Why not just go EMT
the whole way, or, if it's too complicated for pipe bending, just use MC.

"Greg" wrote in message
...
Long ago I did once
try to pull a 12/2 through a 1/2" EMT and while it can be done...

Newer NM-b is smaller than the old TW NM but whenever I have seen EMT
sleeves
the run was a single straight section with no bends so it is pretty easy
to do.
You do have to ream the burrs off the EMT to avoid damage but you should
really
be using a Romex to EMT connector on the end.

On 2004-10-11, J T wrote:

Right... of course I still wonder what kind of situation lends itself to a
half-EMT, half-exposed romex installation between boxes? Why not just go EMT
the whole way, or, if it's too complicated for pipe bending, just use MC.

In may case, I have an unfinished basement, and I ran NMB between the
floor joists above for a lighting circuit. I used EMT sleeve risers
on the boxes I installed for switches.

Cheers, Wayne

On Mon, 11 Oct 2004 11:40:32 -0700, J T wrote
(in article ):

Interesting... I was guessing 12/2 was 1/2 inch wide. Long ago I did once
try to pull a 12/2 through a 1/2" EMT and while it can be done, that stuff
is very, very difficult to get around any sort of bend in a tube that tight.
Even if it is allowed you'd be hard pressed to have a good reason to go to
that kind of trouble, far easier to use single conductors. I imagine 12/3 is
even tougher.

"Wayne Whitney" wrote in message
...
On 2004-10-11, J T wrote:

And, you'd probably be violating code if you used 1/2" EMT technically,
since you can't legally install 12/2 (and probably not even 14/2) in
1/2"
EMT due to fill limits.

Actually, I don't believe this is true. With a single cable, the NEC
allows 53% conduit fill, and 1/2" EMT has an interior diameter of
about 5/8". This yields 0.161 in^2 of usable area. The 12/2 NMB
cable sample I measured is 0.39" x 0.18", and it has to be treated as
a circle of diameter 0.39". This yields a cross-sectional area of
0.119 in^2, which is less than 0.161 in^2. BTW, my sample of 12/3 NMB
cable has a diameter of 0.37", so a single 12/3 NMB cable is OK too.
I don't have a sample of 12/4 here.

Cheers,
Wayne




"Nipples" meaning pipe segments less than 24" are exempt from conduit fill
limitations. You can sleeve 12/3 NM for short straight lengths in 1/2" EMT
or Rigid for that matter without difficulty. This is often done (and
required) when running NM up through a floor.

And yes, you have to carefully ream the cut ends so you don't damage the
cable, but you're always required to do that...

- Kenneth

According to J T :
Interesting... I was guessing 12/2 was 1/2 inch wide. Long ago I did once
try to pull a 12/2 through a 1/2" EMT and while it can be done, that stuff
is very, very difficult to get around any sort of bend in a tube that tight.
Even if it is allowed you'd be hard pressed to have a good reason to go to
that kind of trouble, far easier to use single conductors. I imagine 12/3 is
even tougher.

You can pull 10/2 thru 1/2" PVC. Fortunately, it was _real_ short, without
any bends.
--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.