Hello all:

I have a home built in 1950. Im planning to rewire the home. I looked under the crawlspace and saw that the whole house is wired with wires in flexible metal conduits.

If I can use these conduits to care the new wiring, I dont have to tear up any sheet rock, Except for replacing some of the metal boxesthat may be on the small side.

My electrician friend says that I should be able to run Romex cable through them.

Another friend says that I should just run individual insulated wires.It might be cheaper and easier to work with, he says.

From what I understand both are acceptable in terms of code.

What do you folks advise?

Thanks

Al

On Saturday, December 23, 2017 at 1:50:38 AM UTC-6, Deguza wrote:
Hello all:

I have a home built in 1950. Im planning to rewire the home. I looked under the crawlspace and saw that the whole house is wired with wires in flexible metal conduits.

If I can use these conduits to care the new wiring, I dont have to tear up any sheet rock, Except for replacing some of the metal boxesthat may be on the small side.

My electrician friend says that I should be able to run Romex cable through them.

Another friend says that I should just run individual insulated wires.It might be cheaper and easier to work with, he says.

From what I understand both are acceptable in terms of code.

What do you folks advise?

Thanks

Al


Are you sure it's not BX cable? o_O

[8~{} Uncle Wired Monster

On 12/23/2017 1:50 AM, Deguza wrote:
Hello all:

I have a home built in 1950. Im planning to rewire the home. I
looked under the crawlspace and saw that the whole house is wired
with wires in flexible metal conduits.

If I can use these conduits to care the new wiring, I dont have to
tear up any sheet rock, Except for replacing some of the metal boxes
that may be on the small side.

My electrician friend says that I should be able to run Romex cable through them.

Another friend says that I should just run individual insulated
wires.It might be cheaper and easier to work with, he says.

From what I understand both are acceptable in terms of code.

What do you folks advise?

That's BX armored cable. Why pull wire in the same run; in all
likelihood there's nothing wrong at all with the cable unless it's been
flooded or some other reason.

With BX, the conduit generally served as the ground path so there's
likely not a ground conductor if this is original wiring and there
probably aren't grounded outlets unless some have been added since.

NEC limits the amount of "fill" such that going from 2-wire to 3-wire
the extra ground conductor may exceed allowable but if doesn't NM will
be much harder to pull and there's no point in doing so.

A more definitive answer would be to know what is the purpose behind the
work envisioned.

--

On Fri, 22 Dec 2017 23:50:29 -0800 (PST), Deguza
wrote:

Hello all:

I have a home built in 1950. Im planning to rewire the home. I looked under the crawlspace and saw that the whole house is wired with wires in flexible metal conduits.

If I can use these conduits to care the new wiring, I dont have to tear up any sheet rock, Except for replacing some of the metal boxesthat may be on the small side.

My electrician friend says that I should be able to run Romex cable through them.

Another friend says that I should just run individual insulated wires.It might be cheaper and easier to work with, he says.

From what I understand both are acceptable in terms of code.

What do you folks advise?

Thanks

Al

If it is really FMC (at least 7/8" OD for 1/2") then you can pull in
new wire but I would not try Romex. You probably won't make it
through. Use THHN/THWN. If this stuff is more like 1/2"-5/8" OD it is
BX or AC cable and it is an assembly. You probably can't get the old
wire out and it is very unlikely you will get new wire in.
It is hard enough pulling wire in FMC. You can't use the vacuum trick
to pull in a string and pushing it in is almost impossible if there
are any bends at all. Be sure you pull in a string when you pull out
the old wire. I would use 1/8" nylon if you don't have "jet line" (the
stuff the sparkies use. You don't want it to break.

On Saturday, December 23, 2017 at 10:10:39 AM UTC-5, dpb wrote:
On 12/23/2017 1:50 AM, Deguza wrote:
Hello all:

I have a home built in 1950. Im planning to rewire the home. I
looked under the crawlspace and saw that the whole house is wired
with wires in flexible metal conduits.

If I can use these conduits to care the new wiring, I dont have to
tear up any sheet rock, Except for replacing some of the metal boxes
that may be on the small side.

My electrician friend says that I should be able to run Romex cable through them.

Another friend says that I should just run individual insulated
wires.It might be cheaper and easier to work with, he says.

From what I understand both are acceptable in terms of code.

What do you folks advise?

That's BX armored cable. Why pull wire in the same run; in all
likelihood there's nothing wrong at all with the cable unless it's been
flooded or some other reason.

I guess because he's upgrading all the wiring, and per your later comments,
what he has doesn't have a proper ground, can't be used as part of new
wiring, etc.




With BX, the conduit generally served as the ground path so there's
likely not a ground conductor if this is original wiring and there
probably aren't grounded outlets unless some have been added since.

If it's very old BX, there was no ground back then. Today BX has
a separate ground wire in it, which provides the ground. In between
those two, I guess BX might have been used to provide a ground where
the metal jacket alone was used, but that doesn't provide an adequate
ground, which is why it now has the additional wire.





NEC limits the amount of "fill" such that going from 2-wire to 3-wire
the extra ground conductor may exceed allowable but if doesn't NM will
be much harder to pull and there's no point in doing so.

How would you ever pull anything in BX cable? Even if you theoretically
could get what's in there out, I don't think NM would ever fit inside.






A more definitive answer would be to know what is the purpose behind the
work envisioned.

--

Agree. IDK what he has, because he says an electrician friend suggested
he could run Romex inside, which doesn't make sense to me if he has BX.
But BX would seem to be the most likely thing for a house, not actual
conduit.

On Saturday, December 23, 2017 at 10:20:08 AM UTC-5, BurfordTJustice wrote:
Are these other people goiing to be sleeping in your house every night?


if not do as you wish.



As always, your participation in on topic threads adds nothing. You obviously
know nothing about actual home repair, either because you're totally
clueless or because you're sitting at a Russian troll farm and have no
knowledge of homes in the USA.

You need to check YOUR codes what's good in one place may be bad in another. If your in Chicago both romex and BX are a no go , greenfield is ok to a point - in some cases. Everything must be in pipe in Chicago , Go 20 miles north romex may be permitted.

replying to Deguza, Iggy wrote:
I agree with dpb. It may be flexible conduit, but that practice is very rare.
Armored cable is the best stuff and actually keeps the unexposed wires brand
new. Every armored cable I've re-cut for longer ends that had been cut-down
over the decades were always like new in everyway, my oldest so far were
80-years old. Unless you need a larger gauge wire, I'd either leave what's
there or cut the ends back to re-locate the boxes. However, your friend is
wrong about the Romex replacement idea, you don't know if you now have or will
have cable chewing rodents in the future. Always upgrade and never downgrade.

--
for full context, visit https://www.homeownershub.com/mainte...t-1153703-.htm

On Sat, 23 Dec 2017 16:44:01 GMT, Iggy
m wrote:

replying to Deguza, Iggy wrote:
I agree with dpb. It may be flexible conduit, but that practice is very rare.
Armored cable is the best stuff and actually keeps the unexposed wires brand
new. Every armored cable I've re-cut for longer ends that had been cut-down
over the decades were always like new in everyway, my oldest so far were
80-years old. Unless you need a larger gauge wire, I'd either leave what's
there or cut the ends back to re-locate the boxes. However, your friend is
wrong about the Romex replacement idea, you don't know if you now have or will
have cable chewing rodents in the future. Always upgrade and never downgrade.


New York and Chicago require arboured cable for ratproofing. If
Chicago rerquires EMT it's just to feed the mob.

On Saturday, December 23, 2017 at 11:27:44 AM UTC-5, BurfordTJustice wrote:
Unlike you we know what a supressor does vs a movie prop.

Nice job, moron. You just demonstrated that you can't even spell the
word. Didn't your Russian masters give you enough training in the
English language? And WTF does that have to do with this thread?

On Saturday, December 23, 2017 at 11:44:06 AM UTC-5, Iggy wrote:
replying to Deguza, Iggy wrote:
I agree with dpb. It may be flexible conduit, but that practice is very rare.
Armored cable is the best stuff and actually keeps the unexposed wires brand
new. Every armored cable I've re-cut for longer ends that had been cut-down
over the decades were always like new in everyway, my oldest so far were
80-years old. Unless you need a larger gauge wire, I'd either leave what's
there or cut the ends back to re-locate the boxes.

What he has, as he's described it, very likely can't be used as part of
his upgrade because if it's old BX, it does not have a ground wire in it.
Homes in the 50s had ungrounded receptacles.

replying to trader_4, Iggy wrote:
You're absolutely right IF it's actually flexible conduit for just in the
crawlspace. However, If the entire place is actually BX, then the jacket can
be very successfully used as a ground conductor between a grounding outlet and
a grounding rod. I've done it and have had it done, the ground will be fully
confirmed by any and all Wiring Testers, GFCI Affirmers and other testing
methods.

Sure, a separate ground wire MAY be better, but only due to matched or
slightly better impedance though at much less capacity. 1st the system's
ability needs to be confirmed, then each outlet needs confirmation and
necessary correction. But, he needs to understand that new wire isn't better
nor a guarantee, replacing sound 14-gauge with new 14-gauge is no upgrade and
completely wasted effort for no benefit.

--
for full context, visit https://www.homeownershub.com/mainte...t-1153703-.htm

replying to Clare Snyder, Iggy wrote:
You've got that right! But, an EMT job is real purty.

--
for full context, visit https://www.homeownershub.com/mainte...t-1153703-.htm

On Saturday, December 23, 2017 at 6:14:06 PM UTC-5, Iggy wrote:
replying to trader_4, Iggy wrote:
You're absolutely right IF it's actually flexible conduit for just in the
crawlspace. However, If the entire place is actually BX, then the jacket can
be very successfully used as a ground conductor between a grounding outlet and
a grounding rod.



If you're doing it to code and making it safe it can't be used.
That old BX has no bonding wire inside and the jacket is not reliable
and effective as a ground conductor without it, because it cannot guarantee
the necessary low impedance path. It's a clear NEC violation. Also the primary ground fault current path is not through a ground round, it's
back to the neutral.



I've done it and have had it done, the ground will be fully
confirmed by any and all Wiring Testers, GFCI Affirmers and other testing
methods.

Sure, a separate ground wire MAY be better, but only due to matched or
slightly better impedance though at much less capacity. 1st the system's
ability needs to be confirmed, then each outlet needs confirmation and
necessary correction. But, he needs to understand that new wire isn't better
nor a guarantee, replacing sound 14-gauge with new 14-gauge is no upgrade and
completely wasted effort for no benefit.

--
for full context, visit https://www.homeownershub.com/mainte...t-1153703-.htm

On Sat, 23 Dec 2017 23:14:03 GMT, Iggy
m wrote:

replying to trader_4, Iggy wrote:
You're absolutely right IF it's actually flexible conduit for just in the
crawlspace. However, If the entire place is actually BX, then the jacket can
be very successfully used as a ground conductor between a grounding outlet and
a grounding rod. I've done it and have had it done, the ground will be fully
confirmed by any and all Wiring Testers, GFCI Affirmers and other testing
methods.

Sure, a separate ground wire MAY be better, but only due to matched or
slightly better impedance though at much less capacity. 1st the system's
ability needs to be confirmed, then each outlet needs confirmation and
necessary correction. But, he needs to understand that new wire isn't better
nor a guarantee, replacing sound 14-gauge with new 14-gauge is no upgrade and
completely wasted effort for no benefit.
There are several versions of "bx" cable. The original was just the
spiral jacket - and is no longer considered a ground. The next version
had a "ribbon" or "tape" conductor running the length inside.. The
third version got a bare copper wire ground.

I believe the current versions are called MC and AC. AC is "armored
cable" - steel? armor and aluminum ribbon bonding strip that allows
the armor to be used as a ground (250.118(9)).

MC is "Metal Clad" and has no bonding ribbon, and a full circuit
ground conductor. (article 330) It is an aluminum sheath IIRC.

On Sat, 23 Dec 2017 23:14:04 GMT, Iggy
m wrote:

replying to Clare Snyder, Iggy wrote:
You've got that right! But, an EMT job is real purty.
EMT, properly done, IS a far sight better looking then "BX", but for
residential wiring up here we hide it inside the walls, so even that
awfull looking "romex" looks just fine when the job is
finished.(particularly that new-fangled color-coded plastic covered
stuff!!)

On Saturday, December 23, 2017 at 9:44:06 PM UTC-5, Iggy wrote:
replying to trader_4, Iggy wrote:
Correct, only if you're doing a re-wire is it NEC-illegal,

But of course that is exactly the context of the question asked and the whole thread. He is asking about a re-wire.



though I wouldn't
agree at all that it's inadequate.

Sure, who should we believe? You with opinions or the nec based on real data and facts?



There are plenty of buildings in every town
proving the code wrong daily and who converted very easily to fully grounded
systems with nothing but new outlets and keeping their plumbing grounds.


Which of course, again is not code compliant and would not pass inspection. But keep digging your hole deeper.


Just be careful about the "what's currently legal" stuff, everything out there
was legal at some point and even the remaining knob & tube stuff is still
perfectly fine.

Sure, what's there is grandfathered, but that wasn't the question. The question was about doing an upgrade.


BX just happened to be one of those lucky strikes with the
current code just slightly improving upon those situations and opened the door
for aluminum armor.

--

Just stop already.

In alt.home.repair, on Sat, 23 Dec 2017 23:14:03 GMT, Iggy
m wrote:

replying to trader_4, Iggy wrote:
You're absolutely right IF it's actually flexible conduit for just in the
crawlspace. However, If the entire place is actually BX, then the jacket can
be very successfully used as a ground conductor between a grounding outlet and
a grounding rod. I've done it and have had it done, the ground will be fully
confirmed by any and all Wiring Testers, GFCI Affirmers and other testing
methods.

Sure, a separate ground wire MAY be better, but only due to matched or
slightly better impedance

Is there any relevance to "matched" impedance when dealing with house
current? If it matched, what would it match?

Are you thinking about electronics, not electricity? Like matching
output transformer impedance to speaker impedance.

In fact, what is the point of using the word impedance? Aren't we
talking about plain old resistance, with no capacitative or inductive
component?


though at much less capacity. 1st the system's
ability needs to be confirmed, then each outlet needs confirmation and
necessary correction. But, he needs to understand that new wire isn't better
nor a guarantee, replacing sound 14-gauge with new 14-gauge is no upgrade and
completely wasted effort for no benefit.

On Saturday, December 23, 2017 at 11:53:40 PM UTC-5, micky wrote:
In alt.home.repair, on Sat, 23 Dec 2017 23:14:03 GMT, Iggy
m wrote:

replying to trader_4, Iggy wrote:
You're absolutely right IF it's actually flexible conduit for just in the
crawlspace. However, If the entire place is actually BX, then the jacket can
be very successfully used as a ground conductor between a grounding outlet and
a grounding rod. I've done it and have had it done, the ground will be fully
confirmed by any and all Wiring Testers, GFCI Affirmers and other testing
methods.

Sure, a separate ground wire MAY be better, but only due to matched or
slightly better impedance

Is there any relevance to "matched" impedance when dealing with house
current?

No



If it matched, what would it match?


You're right, there is nothing to match. You just want the impedance of
the ground path to be as low as practically possible.




Are you thinking about electronics, not electricity? Like matching
output transformer impedance to speaker impedance.

In fact, what is the point of using the word impedance? Aren't we
talking about plain old resistance, with no capacitative or inductive
component?



There is always some capacitance and inductance involved. You can
model a cable by a number of inductors in series and capacitors
between them that go across the conductors. At 60hz, it's not much
of a factor. But the ground path on occasion has to serve as the
path for transients, eg a lightning surge. And to that the impedance
of the path matters greatly. Even for a sudden direct short, the
impedance matters, because again, it's not a 60hz event, there are
high frequency components. With more impedance you'll see a higher
voltage on the whole end of the ground path where the fault occure
ed.

I suspect those kind of considerations went into the newer BX type
cables because the ones that still rely on the outer metal jacket
for the ground have included a thin wire inside. I suspect part
or maybe all of it's purpose is to provide a straight, short
path for the current. Because otherwise you already have a long
coiled path for the current in the spiral jacket. It's one
continuous piece of metal from end to end, right? It's just
that it's spiraled onto itself. If the spiral edges make perfect
contact with each other, then it would be like a pipe, a direct
path. If they were perfectly insulated where they contact each
other on every turn, it would look like a very long inductor.
I suspect in practice, it's some of both. Putting that additional
bare wire inside makes it less of an inductor, as well as shortening
the effective length, which lowers both the resistance and impedance.
I suspect that's why they did it.

On Sat, 23 Dec 2017 23:53:36 -0500, micky
wrote:

In alt.home.repair, on Sat, 23 Dec 2017 23:14:03 GMT, Iggy
om wrote:

replying to trader_4, Iggy wrote:
You're absolutely right IF it's actually flexible conduit for just in the
crawlspace. However, If the entire place is actually BX, then the jacket can
be very successfully used as a ground conductor between a grounding outlet and
a grounding rod. I've done it and have had it done, the ground will be fully
confirmed by any and all Wiring Testers, GFCI Affirmers and other testing
methods.

Sure, a separate ground wire MAY be better, but only due to matched or
slightly better impedance

Is there any relevance to "matched" impedance when dealing with house
current? If it matched, what would it match?

Are you thinking about electronics, not electricity? Like matching
output transformer impedance to speaker impedance.

In fact, what is the point of using the word impedance? Aren't we
talking about plain old resistance, with no capacitative or inductive
component?


This is more of a theoretical problem than a demonstrated one but the
thought is that the extra impedance caused by the spiral wraps in the
cable armor might prevent the over current device from operating in a
fault condition. I suppose if the cable was long enough it could be a
problem tho. The "fix" in AC cable was just a thin strip of the armor
material that is actually scrap resulting from the manufacturing
process run along with the conductors that effectively shorts out the
"choke" created by the armor.
The reality is, in 2000, when I tested an old BX job built during
WWII, the cable armor still presented less than an ohm if impedance
at every receptacle in the building. (Using an Ecos ground impedance
tester)
To create this "choke" you would need each revolution of the armor to
be insulated from the one next to it.
Where this is more likely to cause a problem is with point of use
surge protectors that require the ground to be effective. The very
short duration transients will have trouble being shunted out, even
with a fairly low impedance in the armor.

On Sun, 24 Dec 2017 07:53:22 -0500, "BurfordTJustice"
wrote:

Code does not by itself make it safe.....

Code inspections cut the legal responsibility for the contractor.

End of subject.

Not really true at all. In fact most inspectors have sovereign
immunity but the contractors don't.
That means if you want to sue the inspector, you are really trying to
sue the government. The contractor is still wide open to actions. The
fact that an inspector did not find a violation does not insulate the
contractor from a negligence suit. That is why they usually have E&O
insurance.

replying to trader_4, Iggy wrote:
Sorry, it just looks like he's asking if he can re-use what he currently
thinks is flexible conduit for a possibly completely useless non-upgrade. My
"opinion" is what the NEC said and yes using BX's armor as a ground in
existing wiring is completely legal and compliant. You or anyone else saying
60-years of perfect function and reliability is garbage is outright absurd.

I can plug a GFCI or Circuit Tester into a 3-prong adapter in contact with the
cover plate's screw and always get a correct read and have a GFCI outlet test
perfectly all day long with a BX's armor grounding the box and the ground
actually works correctly and as expected. Again, latest code is nothing but
here's our newest tweaks. At no time does the code say its old codes are
garbage or dangerous. They simply say this is only how we want the new stuff.

--
for full context, visit https://www.homeownershub.com/mainte...t-1153703-.htm

replying to Clare Snyder, Iggy wrote:
Yep, I'm just talking about this guy's old and wonderful stuff good for
another 50-years...if that's what it is and not actually empty BX that
literally is flexible conduit.

--
for full context, visit https://www.homeownershub.com/mainte...t-1153703-.htm

replying to micky, Iggy wrote:
No, there's really no relevance to "matched", I was just giving some credit to
the NEC of how a copper or aluminum wire might be a slight improvement over
steel. Thus, Impedance is all of those other words and why it's so vital to
electronics and speakers. Although, that's also why a slight improvement
really doesn't matter when we're talking big dirty power and not transformed
filtered small power. Therefore, why electronics and speakers don't care 1-bit
if there's no ground nor how "approved" a ground is.

--
for full context, visit https://www.homeownershub.com/mainte...t-1153703-.htm

On Sun, 24 Dec 2017 10:33:39 -0500, wrote:

On Sat, 23 Dec 2017 23:53:36 -0500, micky
wrote:

In alt.home.repair, on Sat, 23 Dec 2017 23:14:03 GMT, Iggy
caedfaa9ed1216d60ef78a6f660f5f85_11468@example. com wrote:

replying to trader_4, Iggy wrote:
You're absolutely right IF it's actually flexible conduit for just in the
crawlspace. However, If the entire place is actually BX, then the jacket can
be very successfully used as a ground conductor between a grounding outlet and
a grounding rod. I've done it and have had it done, the ground will be fully
confirmed by any and all Wiring Testers, GFCI Affirmers and other testing
methods.

Sure, a separate ground wire MAY be better, but only due to matched or
slightly better impedance

Is there any relevance to "matched" impedance when dealing with house
current? If it matched, what would it match?

Are you thinking about electronics, not electricity? Like matching
output transformer impedance to speaker impedance.

In fact, what is the point of using the word impedance? Aren't we
talking about plain old resistance, with no capacitative or inductive
component?


This is more of a theoretical problem than a demonstrated one but the
thought is that the extra impedance caused by the spiral wraps in the
cable armor might prevent the over current device from operating in a
fault condition. I suppose if the cable was long enough it could be a
problem tho. The "fix" in AC cable was just a thin strip of the armor
material that is actually scrap resulting from the manufacturing
process run along with the conductors that effectively shorts out the
"choke" created by the armor.
The reality is, in 2000, when I tested an old BX job built during
WWII, the cable armor still presented less than an ohm if impedance
at every receptacle in the building. (Using an Ecos ground impedance
tester)
To create this "choke" you would need each revolution of the armor to
be insulated from the one next to it.
Where this is more likely to cause a problem is with point of use
surge protectors that require the ground to be effective. The very
short duration transients will have trouble being shunted out, even
with a fairly low impedance in the armor.
Causes problems with GFCI devices as well, perhaps?? or AFCI?

On Sun, 24 Dec 2017 10:39:35 -0500, wrote:

On Sun, 24 Dec 2017 07:53:22 -0500, "BurfordTJustice"
wrote:

Code does not by itself make it safe.....

Code inspections cut the legal responsibility for the contractor.

End of subject.

Not really true at all. In fact most inspectors have sovereign
immunity but the contractors don't.
That means if you want to sue the inspector, you are really trying to
sue the government. The contractor is still wide open to actions. The
fact that an inspector did not find a violation does not insulate the
contractor from a negligence suit. That is why they usually have E&O
insurance.

And why if they don't, they REALLY should. Particularly in the
Litigeous States of America.

It is always possible for even the best tradesman to miss something
that on a "bad day" could cause injury or damage that some lawyer
could attempt to take everything he owns.

Either insure orbe litigation-proof (own no assetts)

On Sunday, December 24, 2017 at 10:44:07 AM UTC-5, Iggy wrote:
replying to trader_4, Iggy wrote:
Sorry, it just looks like he's asking if he can re-use what he currently
thinks is flexible conduit for a possibly completely useless non-upgrade.

We have no idea what the extent or purpose of the upgrade is. All
he said is that he's planning to re-wire an old home. And yes, he
asked if he can use what he thinks is flex conduit. But people quickly
pointed out that it's more likely BX cable. In which case the whole
idea of reusing it is pointless, because you can't get the old wire
out and new wire, including a grounding conductor in. It's nuts.

You then posted this:

"However, If the entire place is actually BX, then the jacket can
be very successfully used as a ground conductor between a grounding outlet and
a grounding rod. I've done it and have had it done, the ground will be fully
confirmed by any and all Wiring Testers, GFCI Affirmers and other testing
methods.

Sure, a separate ground wire MAY be better, but only due to matched or
slightly better impedance though at much less capacity."


He can't use the jacket of that old BX as the grounding conductor as part
of his re-wiring/upgrade, because it does not meet current NEC, unless
the cable has the internal bonding wire or a separate ground conductor.
Old BX doesn't have it.





My
"opinion" is what the NEC said and yes using BX's armor as a ground in
existing wiring is completely legal and compliant. You or anyone else saying
60-years of perfect function and reliability is garbage is outright absurd.

Again, try following the thread and the question. He's not talking about
what exists now, he's talking about REWIRING THE HOUSE. That re-wiring
must conform to current NEC.





I can plug a GFCI or Circuit Tester into a 3-prong adapter in contact with the
cover plate's screw and always get a correct read and have a GFCI outlet test
perfectly all day long with a BX's armor grounding the box and the ground
actually works correctly and as expected.

Citing that a GFCI works, is meaningless. One important use of a GFCI
is in circuits with no ground at all, they don't need a ground to function.
And what you can test, what you can see, what you think, doesn't change
what NEC says.


Again, latest code is nothing but
here's our newest tweaks. At no time does the code say its old codes are
garbage or dangerous. They simply say this is only how we want the new stuff.



And of course the whole point is that he's talking about "new stuff".
You can't rewire the house and use old BX with no bond wire or separate
ground conductor as part of the work. For example, if he's adding
another receptacle, he can't do that off the end of the old BX cable.
Not only do you have the cable with no ground issue, if the new
receptacle is in most living areas, to be NEC compliant, it has to
be AFCI protected too.

On Sunday, December 24, 2017 at 10:44:11 AM UTC-5, Iggy wrote:
replying to micky, Iggy wrote:
No, there's really no relevance to "matched", I was just giving some credit to
the NEC of how a copper or aluminum wire might be a slight improvement over
steel. Thus, Impedance is all of those other words and why it's so vital to
electronics and speakers. Although, that's also why a slight improvement
really doesn't matter when we're talking big dirty power and not transformed
filtered small power. Therefore, why electronics and speakers don't care 1-bit
if there's no ground nor how "approved" a ground is.



You just keep digging the hole deeper. Look at any modern electronics
and the incoming power circuitry is always protected by MOVs that are
connected from the hot and neutral to ground for surge protection.
Same thing on phone line inputs and similar. With no ground, there is
nowhere to shunt a surge to before it gets to the electronics. And
the quality of the ground matters too, per the above discussion on
impedance.

On Sun, 24 Dec 2017 11:06:34 -0500, Clare Snyder
wrote:

On Sun, 24 Dec 2017 10:33:39 -0500, wrote:

On Sat, 23 Dec 2017 23:53:36 -0500, micky
wrote:

In alt.home.repair, on Sat, 23 Dec 2017 23:14:03 GMT, Iggy
caedfaa9ed1216d60ef78a6f660f5f85_11468@example .com wrote:

replying to trader_4, Iggy wrote:
You're absolutely right IF it's actually flexible conduit for just in the
crawlspace. However, If the entire place is actually BX, then the jacket can
be very successfully used as a ground conductor between a grounding outlet and
a grounding rod. I've done it and have had it done, the ground will be fully
confirmed by any and all Wiring Testers, GFCI Affirmers and other testing
methods.

Sure, a separate ground wire MAY be better, but only due to matched or
slightly better impedance

Is there any relevance to "matched" impedance when dealing with house
current? If it matched, what would it match?

Are you thinking about electronics, not electricity? Like matching
output transformer impedance to speaker impedance.

In fact, what is the point of using the word impedance? Aren't we
talking about plain old resistance, with no capacitative or inductive
component?


This is more of a theoretical problem than a demonstrated one but the
thought is that the extra impedance caused by the spiral wraps in the
cable armor might prevent the over current device from operating in a
fault condition. I suppose if the cable was long enough it could be a
problem tho. The "fix" in AC cable was just a thin strip of the armor
material that is actually scrap resulting from the manufacturing
process run along with the conductors that effectively shorts out the
"choke" created by the armor.
The reality is, in 2000, when I tested an old BX job built during
WWII, the cable armor still presented less than an ohm if impedance
at every receptacle in the building. (Using an Ecos ground impedance
tester)
To create this "choke" you would need each revolution of the armor to
be insulated from the one next to it.
Where this is more likely to cause a problem is with point of use
surge protectors that require the ground to be effective. The very
short duration transients will have trouble being shunted out, even
with a fairly low impedance in the armor.
Causes problems with GFCI devices as well, perhaps?? or AFCI?

I can't think of a reason why it would. Any choke effect of the armor
would be common mode affecting the other two conductors and cancel
itself out at the GFCI. In fact the coupling into EMT would be a
greater effect. The reality is I have one GFCI circuit here feeding
lights and receptacles around the back yard that is a few hundred feet
long, most in EMT with some RNC and the GFCI is fine with it in spite
of all the hysteria I have heard about the coupling problem.

On Sun, 24 Dec 2017 15:44:03 GMT, Iggy
m wrote:

replying to trader_4, Iggy wrote:
Sorry, it just looks like he's asking if he can re-use what he currently
thinks is flexible conduit for a possibly completely useless non-upgrade. My
"opinion" is what the NEC said and yes using BX's armor as a ground in
existing wiring is completely legal and compliant. You or anyone else saying
60-years of perfect function and reliability is garbage is outright absurd.

I can plug a GFCI or Circuit Tester into a 3-prong adapter in contact with the
cover plate's screw and always get a correct read and have a GFCI outlet test
perfectly all day long with a BX's armor grounding the box and the ground
actually works correctly and as expected. Again, latest code is nothing but
here's our newest tweaks. At no time does the code say its old codes are
garbage or dangerous. They simply say this is only how we want the new stuff.
The issue with the old BX is it works well untill it doesn't. Over
time, particularly when in contact with concrete, ow when subjected to
moisture, the old BX rusts,and the safety ground circuit CAN become
compromized. If and when it does, it is no longer safe - and you don't
know it is no longer safe until something happens that requires it to
be there - and it's not.

This is why code updates are made, requiring solutions with either
less chance of failure, or a more obvious failure mode.

If the old BXcorrodes - not to the point of disintegration and total
circuit failkure, but to the point of poor electrical contact from
"coil to coil" a 100 ft length of BX becomes effectively a 300 foot
long steel (read that as "high resistance" safety ground conductor -
not even taking into account the high frequency effect of the
"impedence" of the "choke".

On Sunday, December 24, 2017 at 11:26:59 AM UTC-5, trader_4 wrote:
On Sunday, December 24, 2017 at 10:44:11 AM UTC-5, Iggy wrote:
replying to micky, Iggy wrote:
No, there's really no relevance to "matched", I was just giving some credit to
the NEC of how a copper or aluminum wire might be a slight improvement over
steel. Thus, Impedance is all of those other words and why it's so vital to
electronics and speakers. Although, that's also why a slight improvement
really doesn't matter when we're talking big dirty power and not transformed
filtered small power. Therefore, why electronics and speakers don't care 1-bit
if there's no ground nor how "approved" a ground is.



You just keep digging the hole deeper. Look at any modern electronics
and the incoming power circuitry is always protected by MOVs that are
connected from the hot and neutral to ground for surge protection.
Same thing on phone line inputs and similar. With no ground, there is
nowhere to shunt a surge to before it gets to the electronics. And
the quality of the ground matters too, per the above discussion on
impedance.

I should have qualified that to say modern electronics that's supplied
with a grounded plug. To those electronic appliances, it does matter
whether or not you have a ground.

On Sunday, December 24, 2017 at 10:39:49 AM UTC-5, wrote:
On Sun, 24 Dec 2017 07:53:22 -0500, "BurfordTJustice"
wrote:

Code does not by itself make it safe.....

Code inspections cut the legal responsibility for the contractor.

End of subject.

Not really true at all. In fact most inspectors have sovereign
immunity but the contractors don't.
That means if you want to sue the inspector, you are really trying to
sue the government. The contractor is still wide open to actions. The
fact that an inspector did not find a violation does not insulate the
contractor from a negligence suit. That is why they usually have E&O
insurance.

Burford's experience is limited to the Russian internet troll farm where he lives in the basement. Do they even have inspectors there?

There are several versions of "bx" cable. The original was just the
spiral jacket - and is no longer considered a ground. The next version
had a "ribbon" or "tape" conductor running the length inside.. The
third version got a bare copper wire ground.

I believe the current versions are called MC and AC. AC is "armored
cable" - steel? armor and aluminum ribbon bonding strip that allows
the armor to be used as a ground (250.118(9)).

MC is "Metal Clad" and has no bonding ribbon, and a full circuit
ground conductor. (article 330) It is an aluminum sheath IIRC.

BX was outlawed in Chicago I believe because people would cut the wires at the same time as the shield so now you use greenfield and add the wires after the shield is cut.

On Sun, 24 Dec 2017 08:26:52 -0800 (PST), trader_4
wrote:

On Sunday, December 24, 2017 at 10:44:11 AM UTC-5, Iggy wrote:
replying to micky, Iggy wrote:
No, there's really no relevance to "matched", I was just giving some credit to
the NEC of how a copper or aluminum wire might be a slight improvement over
steel. Thus, Impedance is all of those other words and why it's so vital to
electronics and speakers. Although, that's also why a slight improvement
really doesn't matter when we're talking big dirty power and not transformed
filtered small power. Therefore, why electronics and speakers don't care 1-bit
if there's no ground nor how "approved" a ground is.



You just keep digging the hole deeper. Look at any modern electronics
and the incoming power circuitry is always protected by MOVs that are
connected from the hot and neutral to ground for surge protection.
Same thing on phone line inputs and similar. With no ground, there is
nowhere to shunt a surge to before it gets to the electronics. And
the quality of the ground matters too, per the above discussion on
impedance.

Most of the things you are talking about only have 2 wire line cords
so the ground is not important at all for any internal protection. The
MOV connects line to neutral, usually with a 250v or so MOV.
When you have a connection (antenna, satellite, cable or phone) you
should have primary inlet protection. This is best done at the
interface where it comes into the house, connected to the service
ground but having supplemental protection at the equipment may do some
good too. That might be compromised by the BX, depending on exactly
how much impedance the armor creates.
I doubt it is worth ripping out walls to fix it tho. If this is really
a concern, you can always fish Romex to those few receptacles. Most of
the stuff in your house will not be affected at all.

On Sun, 24 Dec 2017 11:31:29 -0500, wrote:

On Sun, 24 Dec 2017 11:06:34 -0500, Clare Snyder
wrote:

On Sun, 24 Dec 2017 10:33:39 -0500, wrote:

On Sat, 23 Dec 2017 23:53:36 -0500, micky
wrote:

In alt.home.repair, on Sat, 23 Dec 2017 23:14:03 GMT, Iggy
caedfaa9ed1216d60ef78a6f660f5f85_11468@exampl e.com wrote:

replying to trader_4, Iggy wrote:
You're absolutely right IF it's actually flexible conduit for just in the
crawlspace. However, If the entire place is actually BX, then the jacket can
be very successfully used as a ground conductor between a grounding outlet and
a grounding rod. I've done it and have had it done, the ground will be fully
confirmed by any and all Wiring Testers, GFCI Affirmers and other testing
methods.

Sure, a separate ground wire MAY be better, but only due to matched or
slightly better impedance

Is there any relevance to "matched" impedance when dealing with house
current? If it matched, what would it match?

Are you thinking about electronics, not electricity? Like matching
output transformer impedance to speaker impedance.

In fact, what is the point of using the word impedance? Aren't we
talking about plain old resistance, with no capacitative or inductive
component?


This is more of a theoretical problem than a demonstrated one but the
thought is that the extra impedance caused by the spiral wraps in the
cable armor might prevent the over current device from operating in a
fault condition. I suppose if the cable was long enough it could be a
problem tho. The "fix" in AC cable was just a thin strip of the armor
material that is actually scrap resulting from the manufacturing
process run along with the conductors that effectively shorts out the
"choke" created by the armor.
The reality is, in 2000, when I tested an old BX job built during
WWII, the cable armor still presented less than an ohm if impedance
at every receptacle in the building. (Using an Ecos ground impedance
tester)
To create this "choke" you would need each revolution of the armor to
be insulated from the one next to it.
Where this is more likely to cause a problem is with point of use
surge protectors that require the ground to be effective. The very
short duration transients will have trouble being shunted out, even
with a fairly low impedance in the armor.
Causes problems with GFCI devices as well, perhaps?? or AFCI?

I can't think of a reason why it would. Any choke effect of the armor
would be common mode affecting the other two conductors and cancel
itself out at the GFCI. In fact the coupling into EMT would be a
greater effect. The reality is I have one GFCI circuit here feeding
lights and receptacles around the back yard that is a few hundred feet
long, most in EMT with some RNC and the GFCI is fine with it in spite
of all the hysteria I have heard about the coupling problem.
I was thinking more GFCI outlets - not breakers - not feed-through
--- but still just a question.

On Sunday, December 24, 2017 at 12:31:53 PM UTC-5, wrote:
On Sun, 24 Dec 2017 08:26:52 -0800 (PST), trader_4
wrote:

On Sunday, December 24, 2017 at 10:44:11 AM UTC-5, Iggy wrote:
replying to micky, Iggy wrote:
No, there's really no relevance to "matched", I was just giving some credit to
the NEC of how a copper or aluminum wire might be a slight improvement over
steel. Thus, Impedance is all of those other words and why it's so vital to
electronics and speakers. Although, that's also why a slight improvement
really doesn't matter when we're talking big dirty power and not transformed
filtered small power. Therefore, why electronics and speakers don't care 1-bit
if there's no ground nor how "approved" a ground is.



You just keep digging the hole deeper. Look at any modern electronics
and the incoming power circuitry is always protected by MOVs that are
connected from the hot and neutral to ground for surge protection.
Same thing on phone line inputs and similar. With no ground, there is
nowhere to shunt a surge to before it gets to the electronics. And
the quality of the ground matters too, per the above discussion on
impedance.

Most of the things you are talking about only have 2 wire line cords
so the ground is not important at all for any internal protection. The
MOV connects line to neutral, usually with a 250v or so MOV.
When you have a connection (antenna, satellite, cable or phone) you
should have primary inlet protection. This is best done at the
interface where it comes into the house, connected to the service
ground but having supplemental protection at the equipment may do some
good too. That might be compromised by the BX, depending on exactly
how much impedance the armor creates.
I doubt it is worth ripping out walls to fix it tho. If this is really
a concern, you can always fish Romex to those few receptacles. Most of
the stuff in your house will not be affected at all.

I agree and that's why I made my follow on post. But electronics that
do have a grounded plug, eg computers, laser printer, dishwasher,
refrigerator, washer, dryer, will typically have MOVs that shunt to ground
and the electronics in those will benefit from the protection.

On 12/23/2017 10:44 AM, Iggy wrote:
replying to Deguza, Iggy wrote:
I agree with dpb. It may be flexible conduit, but that practice is very
rare.

Why do you think that?
Particularly in the '50s.

Armored cable is the best stuff and actually keeps the unexposed wires
brand new.

Best?
Better than what

Every armored cable I've re-cut for longer ends that had been cut-down
over the decades were always like new in everyway, my oldest so far were
80-years old.

True for most any wiring.

Unless you need a larger gauge wire, I'd either leave what's
there or cut the ends back to re-locate the boxes. However, your friend is
wrong about the Romex replacement idea, you don't know if you now have
or will
have cable chewing rodents in the future.

So never use Romex?
Did "your friend" suggest using exposed Romex?

Always upgrade and never
downgrade.


So my house, which was originally rigid pipe, should only have rigid
pipe extensions?

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On 12/23/2017 5:14 PM, Iggy wrote:
replying to trader_4, Iggy wrote:
You're absolutely right

If trader's post was repeated I could tell what Iggy was talking about.
But morons using HomeMoanersHub never repeat what they are responding to.

IF it's actually flexible conduit for just in the
crawlspace. However, If the entire place is actually BX, then the jacket
can
be very successfully used as a ground conductor between a grounding
outlet and
a grounding rod. I've done it and have had it done, the ground will be
fully
confirmed by any and all Wiring Testers, GFCI Affirmers and other testing
methods.

So the ground resistance back to the panel is 100 ohms. The testers use
maybe 1 mA to test the ground [and other] wires. That gives a voltage
drop of 0.1 V. So the ground is obviously entirely adequate for, say, a
5 amp ground current.

Plug in testers are very effective in testing whether you have a good
ground connection.

It is the kind of opinion that makes everyone value the HomeMoanersHub.


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On 12/24/2017 9:44 AM, Iggy wrote:
I can plug a GFCI or Circuit Tester into a 3-prong adapter in contact
with the
cover plate's screw and always get a correct read and have a GFCI outlet
test
perfectly all day long with a BX's armor grounding the box and the ground
actually works correctly and as expected.

A repeat of the expected quality of advice from HomeMoanersHub.

(It is actually rather easy to test ground quality.)

Again, latest code is nothing but
here's our newest tweaks. At no time does the code say its old codes are
garbage or dangerous. They simply say this is only how we want the new
stuff.

Not exactly.

Like for the common maintenance of replacing a receptacle:
- if the NEC requires an added receptacle be GFCI protected, the
replacement must be GFCI protected
- if the NEC requires an added receptacle be AFCI protected the
replacement must be AFCI protected
- if the NEC requires an added receptacle be 'childproof' the
replacement must be 'childproof'
- if the NEC requires an added receptacle be weather resistant the
replacement must be weather resistant.

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On 12/24/2017 9:33 AM, wrote:
On Sat, 23 Dec 2017 23:53:36 -0500, micky
wrote:

In fact, what is the point of using the word impedance? Aren't we
talking about plain old resistance, with no capacitative or inductive
component?


This is more of a theoretical problem than a demonstrated one but the
thought is that the extra impedance caused by the spiral wraps in the
cable armor might prevent the over current device from operating in a
fault condition.

I always heard it was the resistance of the much longer length of much
smaller cross-section, maybe low conductivity steel, if the spiral did
not bond to the adjacent spirals.
But impedance includes more.

I suppose if the cable was long enough it could be a
problem tho. The "fix" in AC cable was just a thin strip of the armor
material that is actually scrap resulting from the manufacturing
process run along with the conductors that effectively shorts out the
"choke" created by the armor.
The reality is, in 2000, when I tested an old BX job built during
WWII, the cable armor still presented less than an ohm if impedance
at every receptacle in the building. (Using an Ecos ground impedance
tester)
To create this "choke" you would need each revolution of the armor to
be insulated from the one next to it.
Where this is more likely to cause a problem is with point of use
surge protectors that require the ground to be effective.

Those protectors do not work primarily by earthing a surge. They work
primarily by clamping the voltage on ALL the wires going to protected
equipment to the 'ground' at the protector.

If you have H-N-G Romex, and there is 6kV at the panel, you have H
supplying the protector and H-G sinking the surge. The voltage of the
'ground' at the protector will be about 2kV with respect to the 'ground'
at the panel. But the voltage from ALL the wires to the protected
equipment is limited to a safe value.

Because a 'surge' is a very short duration event, there are relatively
high frequency current components. That means the inductance of wires
(H, N & G) is more important than the resistance. The current, and thus
energy, that can reach a point of use protector is surprisingly small.

The likely much larger current from the panel to the earthing
electrode(s) is similarly limited, and the panel 'ground'-to-earth
voltage may be very high.

(You probably agree with most or all of this.)

The very
short duration transients will have trouble being shunted out, even
with a fairly low impedance in the armor.

Protection is not primarily by shunting to earth.

If you have only H and N as effective conductors, there is H supplying
the protector and N sinking the surge. If there is 6kV at the panel the
voltage of the 'ground' at the protector will be about 3kV with respect
to the 'ground' at the panel. But the voltage between the wires to the
protected equipment is still limited to a safe value.


=============================================
If an electrician suggests pulling Romex into flex (other than limited
special circumstances) their opinions are not worth listening to.

BX has always been a tradename for an example of type AC wiring.

IMHO a circuit wired in old BX can be extended. (Your opinion?)

(The extension would often have to be AFCI protected. One method (which
may not be the best) is to wire it through an AFCI receptacle where the
new part of the circuit originates.)


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