Can I use the old flexible conduit?

Hello all:
I have a home built in 1950. I’m planning to rewire the home. I loo ked 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 don’t have t o 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 mi ght 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
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On 12/23/2017 1:50 AM, Deguza wrote:

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.
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On Saturday, December 23, 2017 at 10:10:39 AM UTC-5, dpb wrote:

e to

ough them.

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.

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.

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.

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.
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wrote:

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

New York and Chicago require arboured cable for ratproofing. If Chicago rerquires EMT it's just to feed the mob.
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replying to Clare Snyder, Iggy wrote: You've got that right! But, an EMT job is real purty.
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On Sat, 23 Dec 2017 23:14:04 GMT, Iggy

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!!)
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On Saturday, December 23, 2017 at 11:44:06 AM UTC-5, Iggy wrote:

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.
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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.
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On Saturday, December 23, 2017 at 6:14:06 PM UTC-5, Iggy wrote:

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

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replying to trader_4, Iggy wrote: Correct, only if you're doing a re-wire is it NEC-illegal, though I wouldn't agree at all that it's inadequate. 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.

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. 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.
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On Saturday, December 23, 2017 at 9:44:06 PM UTC-5, Iggy wrote:

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

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

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

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

Just stop already.
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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.
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On Sunday, December 24, 2017 at 10:44:07 AM UTC-5, Iggy wrote:

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

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

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.

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

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

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".
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On 12/24/2017 9:44 AM, Iggy wrote:

A repeat of the expected quality of advice from HomeMoanersHub.
(It is actually rather easy to test ground quality.)

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

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.
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On Sun, 24 Dec 2017 10:39:35 -0500, snipped-for-privacy@aol.com wrote:

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)
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