Bx that's not grounding?
- Thread starter ritelec
- Start date
- Status
Most definitely true. There were reportedly enough fires as a result that it "outlawed" in at least one of our TN cities for years. I am told the problem arose from the fact that with the loosely wound steel metal jacket, the low resistant ground path could become a heater in the event of a short.
Once the now present bond wire was added the problem was resolved.
Once the now present bond wire was added the problem was resolved.
- Location
- New Jersey
- Occupation
- Journeyman Electrician
Although the "newer" stuff after about 1953 contained the bonding strip the cable that predated that was still suitable for use as an EGC.
- Location
- Placerville, CA, USA
- Occupation
- Retired PV System Designer
Suitable in the sense of recognized for use as an EGC, at the time it was sold, by NEC and UL, not necessarily deserving that recognition in hindsight....
- Location
- New Jersey
- Occupation
- Journeyman Electrician
I would treat the same way you would approach reduced sized EGC's in NM cable.
mjf
Senior Member
What are you looking for?
Think I got it.
There is nothing. No article.
Treat it as a egc. The way I've been treating it.
Even the older bx.
Correct?
I think Infinity is saying you treat the NM cable with smaller EGC the same way as you treat regular NM cable.
Just treat the old BX cable as a regular BX cable. I am sure if it sees a fault current the breaker will respond.
- Location
- Placerville, CA, USA
- Occupation
- Retired PV System Designer
Just do not try to use the sheath as a current carrying conductor. :lol:
- Location
- New Jersey
- Occupation
- Journeyman Electrician
I know of no document that says that an AC or NM cable that was code complaint when installed is suddenly not code compliant.
- Location
- Placerville, CA, USA
- Occupation
- Retired PV System Designer
I would say only if it was recalled, which apparently it was not.
On the other hand FPE breakers and panels were never actually recalled either, and are still technically code compliant I guess. It is true AFAIK that the UL listing was revoked for some of those components.
mjf
Senior Member
Maybe I'm wrong, but my understanding is that I am not allowed to extend an existing circuit run with NM cable with reduced size EGC.
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
I think the meaning there was, consider the fact it once was compliant, now it isn't, but the existing is technically still compliant. If you have something existing proceed with caution. Leaving it in place is not necessarily wrong, extending it is not so clear as to whether it is right or wrong.
Replacement is a good idea whenever possible.
I don't think there is a code section that will say/support your statement, except the EGC has to be sized per 250.122.
Then again, you can always protect the circuit by a GFCI if it comes down to "you can not extend a circuit with an undersized EGC"
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
Though it is not a bad idea to use the GFCI if the EGC is too small, I don't think NEC recognizes this as a way around too small of a EGC, it only permits it as a way around no EGC for existing wiring that was once compliant without an EGC.
PetrosA
Senior Member
- Location
- Lancaster, Pennsylvania
I don't trust it as a EGC for handling fault current. I've seen it in houses with brand new panels and breakers, and shorting the hot to the sheath just makes a humming sound in the walls. I always recommend installing GFI breakers on old BX circuits. Its current carrying capacity is generally enough for items that need a ground to function properly, like a UPS, but not enough for a short circuit.
- Status