I'm in the process of buying a house and the lower level is an
unfinished basement. There is NM cable drooping unsupported
under the joists to single bulb light fixtures. Naturally I want
to get this fixed as soon as possible. I've been told to just
staple the wire to the bottom of the joists, but I believe this
violates NEC 334.15(C). Even if it didn't, it would look awful
and possibly cause problems someday when I finish the basement.

So the solution is to drill holes in the joists and rewire.
However, there is a hot air duct (uninsulated) that runs parallel
to and between the joists that the wiring has to cross.

How should this be handled? Does NM cable have to protected from
the potentially hot duct? Should it be run in a conduit? How
should I route the cable around the duct?

Thanks
-T

"Tara Lynn" wrote in message
...
I'm in the process of buying a house and the lower level is an
unfinished basement. There is NM cable drooping unsupported
under the joists to single bulb light fixtures. Naturally I want
to get this fixed as soon as possible. I've been told to just
staple the wire to the bottom of the joists, but I believe this
violates NEC 334.15(C). Even if it didn't, it would look awful
and possibly cause problems someday when I finish the basement.

So the solution is to drill holes in the joists and rewire.
However, there is a hot air duct (uninsulated) that runs parallel
to and between the joists that the wiring has to cross.

How should this be handled? Does NM cable have to protected from
the potentially hot duct? Should it be run in a conduit? How
should I route the cable around the duct?

Thanks
-T

Stapling the wire up with the proper staples is done every day and is the
accepted method of straping NM. As to the bottom of the joists, I would not.
Every time I put something on the bottom of a joist I had to move it. Drill
a 3/4 inch hole in the center of the joist and run the cable there. NM
should never touch something hot. A couple of inches clearance is fine.

In article oKKUc.66948$Lj.39636@fed1read03, "SQLit" wrote:

"Tara Lynn" wrote in message
...
I'm in the process of buying a house and the lower level is an
unfinished basement. There is NM cable drooping unsupported
under the joists to single bulb light fixtures. Naturally I want
to get this fixed as soon as possible. I've been told to just
staple the wire to the bottom of the joists, but I believe this
violates NEC 334.15(C). Even if it didn't, it would look awful
and possibly cause problems someday when I finish the basement.

So the solution is to drill holes in the joists and rewire.
However, there is a hot air duct (uninsulated) that runs parallel
to and between the joists that the wiring has to cross.

How should this be handled? Does NM cable have to protected from
the potentially hot duct? Should it be run in a conduit? How
should I route the cable around the duct?

Thanks
-T

Stapling the wire up with the proper staples is done every day and is the
accepted method of straping NM.

Not when it *crosses* the joists, it's not. The NEC _specifically_prohibits_
that practice. Stapling NM that runs parallel to a joist, to the face of that
joist, is fine.

As to the bottom of the joists, I would not.
Every time I put something on the bottom of a joist I had to move it. Drill
a 3/4 inch hole in the center of the joist and run the cable there. NM
should never touch something hot. A couple of inches clearance is fine.


And how does he get around the duct?

"Doug Miller" wrote in message
m...
In article oKKUc.66948$Lj.39636@fed1read03, "SQLit"
wrote:

"Tara Lynn" wrote in message
...
I'm in the process of buying a house and the lower level is an
unfinished basement. There is NM cable drooping unsupported
under the joists to single bulb light fixtures. Naturally I want
to get this fixed as soon as possible. I've been told to just
staple the wire to the bottom of the joists, but I believe this
violates NEC 334.15(C). Even if it didn't, it would look awful
and possibly cause problems someday when I finish the basement.

So the solution is to drill holes in the joists and rewire.
However, there is a hot air duct (uninsulated) that runs parallel
to and between the joists that the wiring has to cross.

How should this be handled? Does NM cable have to protected from
the potentially hot duct? Should it be run in a conduit? How
should I route the cable around the duct?

Thanks
-T

Stapling the wire up with the proper staples is done every day and is the
accepted method of straping NM.

Not when it *crosses* the joists, it's not. The NEC
_specifically_prohibits_
that practice. Stapling NM that runs parallel to a joist, to the face of
that
joist, is fine.

As to the bottom of the joists, I would not.
Every time I put something on the bottom of a joist I had to move it.
Drill
a 3/4 inch hole in the center of the joist and run the cable there. NM
should never touch something hot. A couple of inches clearance is fine.


And how does he get around the duct?

I had a house like that. The "duct" was the space between the joists with
sheet metal nailed to the bottom of the joists. I hired an electrician to
wire from one side to the other. He went all the way around the cellar, said
there was no other way to cross the duct.

Bob

"rck" wrote:

I had a house like that. The "duct" was the space between the joists with
sheet metal nailed to the bottom of the joists. I hired an electrician to
wire from one side to the other. He went all the way around the cellar, said
there was no other way to cross the duct.

Must be a recent code change in your area or overkill. Those types of ducts are
usually return air so temp is not a concern. There wouldn't have been any
problem drilling a hole on each side and running the romex straight through.
Caulk the holes when done.

In article k.net, "rck" wrote:

I had a house like that. The "duct" was the space between the joists with
sheet metal nailed to the bottom of the joists. I hired an electrician to
wire from one side to the other. He went all the way around the cellar, said
there was no other way to cross the duct.

Yes, there was: nail a 1x4 across the joists below the duct, and staple the
NM cable to the 1x4. This *does* comply with the NEC.

In article , Tara Lynn wrote:
I'm in the process of buying a house and the lower level is an
unfinished basement. There is NM cable drooping unsupported
under the joists to single bulb light fixtures. Naturally I want
to get this fixed as soon as possible. I've been told to just
staple the wire to the bottom of the joists, but I believe this
violates NEC 334.15(C). Even if it didn't, it would look awful
and possibly cause problems someday when I finish the basement.

Correct, that *is* a code violation. However, the code does explicitly permit
NM cable to be stapled to running boards that cross the joists. So wherever
you need to cross joists, nail a 1x4 to the joists and staple the cable to the
1x4. When the cable runs parallel to a joist, code permits (requires, in fact)
that it be fastened to the face of the joist.

So the solution is to drill holes in the joists and rewire.
However, there is a hot air duct (uninsulated) that runs parallel
to and between the joists that the wiring has to cross.

How should this be handled? Does NM cable have to protected from
the potentially hot duct? Should it be run in a conduit? How
should I route the cable around the duct?

A 1x4 across the joists solves *all* of those issues.

"Clark W. Griswold, Jr." 73115 dot 1041 at compuserve dot com wrote in
message ...
"rck" wrote:

I had a house like that. The "duct" was the space between the joists with
sheet metal nailed to the bottom of the joists. I hired an electrician to
wire from one side to the other. He went all the way around the cellar,
said
there was no other way to cross the duct.

Must be a recent code change in your area or overkill. Those types of
ducts are
usually return air so temp is not a concern. There wouldn't have been any
problem drilling a hole on each side and running the romex straight
through.
Caulk the holes when done.

While the NEC does allow one to pass a Romex type cable straight through a
cold air return as described, a safer method, and also permited by code,
would be to install a 1/2" EMT with a connector attached at each end (to
serve as bushings) and pass the Romex through the conduit.

then the conduit has to be bonded
"volts500" wrote in message
...

"Clark W. Griswold, Jr." 73115 dot 1041 at compuserve dot com wrote in
message ...
"rck" wrote:

I had a house like that. The "duct" was the space between the joists
with
sheet metal nailed to the bottom of the joists. I hired an electrician
to
wire from one side to the other. He went all the way around the cellar,
said
there was no other way to cross the duct.

Must be a recent code change in your area or overkill. Those types of
ducts are
usually return air so temp is not a concern. There wouldn't have been
any
problem drilling a hole on each side and running the romex straight
through.
Caulk the holes when done.

While the NEC does allow one to pass a Romex type cable straight through a
cold air return as described, a safer method, and also permited by code,
would be to install a 1/2" EMT with a connector attached at each end (to
serve as bushings) and pass the Romex through the conduit.

From: "Shake-Hull"

then the conduit has to be bonded

So use PVC

"volts500" wrote in message
m...

"Clark W. Griswold, Jr." 73115 dot 1041 at compuserve dot com wrote in
message ...
"rck" wrote:

I had a house like that. The "duct" was the space between the joists
with
sheet metal nailed to the bottom of the joists. I hired an electrician
to
wire from one side to the other. He went all the way around the cellar,
said
there was no other way to cross the duct.

Must be a recent code change in your area or overkill. Those types of
ducts are
usually return air so temp is not a concern. There wouldn't have been
any
problem drilling a hole on each side and running the romex straight
through.
Caulk the holes when done.

While the NEC does allow one to pass a Romex type cable straight through a
cold air return as described, a safer method, and also permited by code,
would be to install a 1/2" EMT with a connector attached at each end (to
serve as bushings) and pass the Romex through the conduit.

According to volts500 :
While the NEC does allow one to pass a Romex type cable straight through a
cold air return as described, a safer method, and also permited by code,
would be to install a 1/2" EMT with a connector attached at each end (to
serve as bushings) and pass the Romex through the conduit.

In Canada, the CEC does not permit you to do that. Hint: if the wire
ever overheats, it's injecting noxious fumes _directly_ into your air
handling. I'm surprised the NEC permits it.

[That said, I _have_ seen it in older homes at least.]

There's an exception for teflon coated wire (certain types of CAT-5 for
example). And conduit of course. If you use EMT, you could probably
get away with strapping it to the ducting for ground.
--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.

In sci.engr.electrical.compliance Doug Miller wrote:
| In article k.net, "rck" wrote:
|
|I had a house like that. The "duct" was the space between the joists with
|sheet metal nailed to the bottom of the joists. I hired an electrician to
|wire from one side to the other. He went all the way around the cellar, said
|there was no other way to cross the duct.
|
| Yes, there was: nail a 1x4 across the joists below the duct, and staple the
| NM cable to the 1x4. This *does* comply with the NEC.

On the side of the 1x4, right?

--
-----------------------------------------------------------------------------
| Phil Howard KA9WGN | http://linuxhomepage.com/ http://ham.org/ |
| (first name) at ipal.net | http://phil.ipal.org/ http://ka9wgn.ham.org/ |
-----------------------------------------------------------------------------

In sci.engr.electrical.compliance Chris Lewis wrote:
| According to volts500 :
| While the NEC does allow one to pass a Romex type cable straight through a
| cold air return as described, a safer method, and also permited by code,
| would be to install a 1/2" EMT with a connector attached at each end (to
| serve as bushings) and pass the Romex through the conduit.
|
| In Canada, the CEC does not permit you to do that. Hint: if the wire
| ever overheats, it's injecting noxious fumes _directly_ into your air
| handling. I'm surprised the NEC permits it.
|
| [That said, I _have_ seen it in older homes at least.]
|
| There's an exception for teflon coated wire (certain types of CAT-5 for
| example). And conduit of course. If you use EMT, you could probably
| get away with strapping it to the ducting for ground.

I wouldn't trust ducting for ground. How about a PVC conduit throught
the duct?

--
-----------------------------------------------------------------------------
| Phil Howard KA9WGN | http://linuxhomepage.com/ http://ham.org/ |
| (first name) at ipal.net | http://phil.ipal.org/ http://ka9wgn.ham.org/ |
-----------------------------------------------------------------------------

According to :
| There's an exception for teflon coated wire (certain types of CAT-5 for
| example). And conduit of course. If you use EMT, you could probably
| get away with strapping it to the ducting for ground.

I wouldn't trust ducting for ground. How about a PVC conduit throught
the duct?

If the wire overheated or in case of a fire, you'd get toxic fumes in
the plenum from the PVC and shortly thereafter, from the romex too.
That's why (we) ban bare romex in air plenums in the first place - toxic
fumes from plastic sheathing...

Given it's only a short sleeve buried _inside_ the ducting, as long as
it had the proper bushings at either end, I doubt that an inspector
would care if it was grounded or not.

Better still, use a PVC conduit sleeve to route the wire _under_ the plenum.
Just don't go _through_ the plenum. The PVC conduit is sufficient physical
protection for bridging the joists, even without the sheet metal on the
bottom of the plenum.
--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.

On Wed, 18 Aug 2004 21:37:13 GMT, someone wrote:

I had a house like that. The "duct" was the space between the joists with
sheet metal nailed to the bottom of the joists. I hired an electrician to
wire from one side to the other. He went all the way around the cellar, said
there was no other way to cross the duct.

But that should be for reasons of physical protection as from puncture
& abrasion, not heat? (Same reason as not to run it under the
joists.) Because a "hot" air duct is just "warm", its not hot enought
to melt the cable. I'd think a "hot" thing would be like smoke pipe
from a conventional furnace.

But it still doesn't get him under the duct. Can he furr and go
between the furring strips? Does he really need flush clear to bottom
of joist, or could the future (speculative if ever) finish go on the
furring or on tracks anyway? What's more important to him, or will he
insist on a combo that can't be done?

-v.

In sci.engr.electrical.compliance Chris Lewis wrote:
| According to :
| | There's an exception for teflon coated wire (certain types of CAT-5 for
| | example). And conduit of course. If you use EMT, you could probably
| | get away with strapping it to the ducting for ground.
|
| I wouldn't trust ducting for ground. How about a PVC conduit throught
| the duct?
|
| If the wire overheated or in case of a fire, you'd get toxic fumes in
| the plenum from the PVC and shortly thereafter, from the romex too.
| That's why (we) ban bare romex in air plenums in the first place - toxic
| fumes from plastic sheathing...

So what non-metallic can be used?


| Given it's only a short sleeve buried _inside_ the ducting, as long as
| it had the proper bushings at either end, I doubt that an inspector
| would care if it was grounded or not.

But if the code requires it be grounded, then this is not the course I
would take.


| Better still, use a PVC conduit sleeve to route the wire _under_ the plenum.
| Just don't go _through_ the plenum. The PVC conduit is sufficient physical
| protection for bridging the joists, even without the sheet metal on the
| bottom of the plenum.

Then you're committing space between any future ceiling finish and the
joists, in which case the crossmember could do the job, too.

--
-----------------------------------------------------------------------------
| Phil Howard KA9WGN | http://linuxhomepage.com/ http://ham.org/ |
| (first name) at ipal.net | http://phil.ipal.org/ http://ka9wgn.ham.org/ |
-----------------------------------------------------------------------------

According to :
In sci.engr.electrical.compliance Chris Lewis wrote:
| According to :
| | There's an exception for teflon coated wire (certain types of CAT-5 for
| | example). And conduit of course. If you use EMT, you could probably
| | get away with strapping it to the ducting for ground.

| I wouldn't trust ducting for ground. How about a PVC conduit throught
| the duct?

| If the wire overheated or in case of a fire, you'd get toxic fumes in
| the plenum from the PVC and shortly thereafter, from the romex too.
| That's why (we) ban bare romex in air plenums in the first place - toxic
| fumes from plastic sheathing...

So what non-metallic can be used?

Essentially none. Consumer-available non-metallic conduit is pretty well
all PVC. Almost all plastics have a noxious fumes issue anyway.

| Better still, use a PVC conduit sleeve to route the wire _under_ the plenum.
| Just don't go _through_ the plenum. The PVC conduit is sufficient physical
| protection for bridging the joists, even without the sheet metal on the
| bottom of the plenum.

Then you're committing space between any future ceiling finish and the
joists,

For the most part you'd be at least strapping the bottoms of the joists for
a ceiling finish, no matter how you routed the wire, so, you're losing that
3/4" of headroom anyway.

in which case the crossmember could do the job, too.

True enough.
--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.

(Chris Lewis) wrote:

| If the wire overheated or in case of a fire, you'd get toxic fumes in
| the plenum from the PVC and shortly thereafter, from the romex too.
| That's why (we) ban bare romex in air plenums in the first place - toxic
| fumes from plastic sheathing...

So what non-metallic can be used?

Essentially none. Consumer-available non-metallic conduit is pretty well
all PVC. Almost all plastics have a noxious fumes issue anyway.


A little bit of reality goes a long ways in this situation. While I wouldn't run
romex for any length inside a plenum, crossing 18" of floor joist is not a major
threat to the occupants of the building. If there is enough flame to burn
through the plenum and vaporize 18 inches of plastic, the occupants have far
worse problems to deal with.

In sci.engr.electrical.compliance Chris Lewis wrote:
| According to :
| So what non-metallic can be used?
|
| Essentially none. Consumer-available non-metallic conduit is pretty well
| all PVC. Almost all plastics have a noxious fumes issue anyway.

What about wood?

What I mean is a tube made of wood, with a hole drilled down the middle
of sufficient size to hold the cable with sufficient heat dissipation.
Maybe it would be the same wood as the joists.

--
-----------------------------------------------------------------------------
| Phil Howard KA9WGN | http://linuxhomepage.com/ http://ham.org/ |
| (first name) at ipal.net | http://phil.ipal.org/ http://ka9wgn.ham.org/ |
-----------------------------------------------------------------------------

According to Clark W. Griswold, Jr. 73115 dot 1041 at compuserve dot com:
(Chris Lewis) wrote:

| If the wire overheated or in case of a fire, you'd get toxic fumes in
| the plenum from the PVC and shortly thereafter, from the romex too.
| That's why (we) ban bare romex in air plenums in the first place - toxic
| fumes from plastic sheathing...

So what non-metallic can be used?

Essentially none. Consumer-available non-metallic conduit is pretty well
all PVC. Almost all plastics have a noxious fumes issue anyway.

A little bit of reality goes a long ways in this situation. While I wouldn't run
romex for any length inside a plenum, crossing 18" of floor joist is not a major
threat to the occupants of the building. If there is enough flame to burn
through the plenum and vaporize 18 inches of plastic, the occupants have far
worse problems to deal with.

Of course, the incremental risk of 18" worth of PVC isn't very high.

It's not hard to see that hot air entering the return vent could melt the PVC
and produce fumes that are 100% captured and ejected into other rooms, adding
quite a bit of toxic fume load to prevent occupants from waking up - toxic
fumes directly generated from the fire tend to rise away from the flame point,
and not go into a return duct (which is on or near the floor).

I'm sure the rule is primarily focused at using the duct for a raceway, but they
decided to simplify it as much as possible - it generally doesn't cause that
much of a hardship anyway.

It's more of a hardship in buildings which use dropped ceilings as a air plenum.
Here, _any_ wire in a dropped ceiling used as a plenum _must_ be in conduit,
tho, I believe they now accept teflon (despite the fact that at higher
temperatures teflon produces _really_ nasty fumes).
--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.

"Shake-Hull" wrote in message
. ..

then the conduit has to be bonded

Short sections of EMT, as applied in this case, are not required to be
bonded. If one is really concerned about bonding the EMT, then extend one
end of the EMT to a metal box mounted on the next joist, run the cable into
the box and ground the EMT and the box with the Romex equipment ground wire.
While a conduit isn't required in the first place in this case, it makes for
a better installation because the EMT would not allow toxic fumes from the
Romex cable to enter the cold air return duct......a PVC conduit would just
add to it.


"volts500" wrote in message
...

"Clark W. Griswold, Jr." 73115 dot 1041 at compuserve dot com wrote in
message ...
"rck" wrote:

I had a house like that. The "duct" was the space between the joists
with
sheet metal nailed to the bottom of the joists. I hired an
electrician
to
wire from one side to the other. He went all the way around the
cellar,
said
there was no other way to cross the duct.

Must be a recent code change in your area or overkill. Those types of
ducts are
usually return air so temp is not a concern. There wouldn't have been
any
problem drilling a hole on each side and running the romex straight
through.
Caulk the holes when done.

While the NEC does allow one to pass a Romex type cable straight through
a
cold air return as described, a safer method, and also permited by
code,
would be to install a 1/2" EMT with a connector attached at each end (to
serve as bushings) and pass the Romex through the conduit.

In sci.engr.electrical.compliance volts500 wrote:

| "Shake-Hull" wrote in message
| . ..
|
| then the conduit has to be bonded
|
| Short sections of EMT, as applied in this case, are not required to be
| bonded. If one is really concerned about bonding the EMT, then extend one
| end of the EMT to a metal box mounted on the next joist, run the cable into
| the box and ground the EMT and the box with the Romex equipment ground wire.
| While a conduit isn't required in the first place in this case, it makes for
| a better installation because the EMT would not allow toxic fumes from the
| Romex cable to enter the cold air return duct......a PVC conduit would just
| add to it.

What about a ceramic conduit? They used to make those a long time ago.
It was called K&T. So we can just adapt the tubes to be larger, hold a
whole cable instead of one wire, and run through a duct instead a single
joist. Maybe glass (not fiberglass) would also work.

--
-----------------------------------------------------------------------------
| Phil Howard KA9WGN | http://linuxhomepage.com/ http://ham.org/ |
| (first name) at ipal.net | http://phil.ipal.org/ http://ka9wgn.ham.org/ |
-----------------------------------------------------------------------------

According to :
In sci.engr.electrical.compliance volts500 wrote:

What about a ceramic conduit? They used to make those a long time ago.
It was called K&T. So we can just adapt the tubes to be larger, hold a
whole cable instead of one wire, and run through a duct instead a single
joist. Maybe glass (not fiberglass) would also work.

Have you ever tried to stretch ceramic conduit? ;-)

I suspect you'd get into trouble with this practise, because the thermal
insulation value can be quite high. K&T materials simply aren't approved
anymore.
--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.

In sci.engr.electrical.compliance Chris Lewis wrote:

| According to :
| In sci.engr.electrical.compliance volts500 wrote:
|
| What about a ceramic conduit? They used to make those a long time ago.
| It was called K&T. So we can just adapt the tubes to be larger, hold a
| whole cable instead of one wire, and run through a duct instead a single
| joist. Maybe glass (not fiberglass) would also work.
|
| Have you ever tried to stretch ceramic conduit? ;-)
|
| I suspect you'd get into trouble with this practise, because the thermal
| insulation value can be quite high. K&T materials simply aren't approved
| anymore.

Why would it need to be stretched? You just drill a hole in each joist
that is the wall of the duct, and slip the conduit across from one to the
other, and fasten it in place so it can't slip out. Now you have a path
through the ductway that is isolated from the duct itself.

This is not a long path. Select a tube wide enough to allow air to flow
through it (between the two ends, not into the duct) with the cable to be
used.

--
-----------------------------------------------------------------------------
| Phil Howard KA9WGN | http://linuxhomepage.com/ http://ham.org/ |
| (first name) at ipal.net | http://phil.ipal.org/ http://ka9wgn.ham.org/ |
-----------------------------------------------------------------------------

According to :
In sci.engr.electrical.compliance Chris Lewis wrote:

| According to :
| In sci.engr.electrical.compliance volts500 wrote:

| What about a ceramic conduit? They used to make those a long time ago.
| It was called K&T. So we can just adapt the tubes to be larger, hold a
| whole cable instead of one wire, and run through a duct instead a single
| joist. Maybe glass (not fiberglass) would also work.

| Have you ever tried to stretch ceramic conduit? ;-)

Why would it need to be stretched?

I was referring to the "just adapt the tubes to be larger" remark. If there
ain't one stock, you'd have to make the tube yourself. That seems a bit
overkill ;-)
--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.

In sci.engr.electrical.compliance Chris Lewis wrote:
| According to :
| In sci.engr.electrical.compliance Chris Lewis wrote:
|
| | According to :
| | In sci.engr.electrical.compliance volts500 wrote:
|
| | What about a ceramic conduit? They used to make those a long time ago.
| | It was called K&T. So we can just adapt the tubes to be larger, hold a
| | whole cable instead of one wire, and run through a duct instead a single
| | joist. Maybe glass (not fiberglass) would also work.
|
| | Have you ever tried to stretch ceramic conduit? ;-)
|
| Why would it need to be stretched?
|
| I was referring to the "just adapt the tubes to be larger" remark. If there
| ain't one stock, you'd have to make the tube yourself. That seems a bit
| overkill ;-)

That was in reference to the smaller (narrower and shorter) tubes used in
old K&T wiring, vs. the wider (for a whole cable) and longer (to go between
two joists to cross the duct) we'd need.

--
-----------------------------------------------------------------------------
| Phil Howard KA9WGN | http://linuxhomepage.com/ http://ham.org/ |
| (first name) at ipal.net | http://phil.ipal.org/ http://ka9wgn.ham.org/ |
-----------------------------------------------------------------------------