Armored Cable: Type AC - ECN Electrical Forums

I have a length of 8AWG Type AC cable that at one time ran from the panel to an electric cooktop (since replaced by a natural gas cooktop...)

I guess the cable is considered "8-3" as it has one each of a white, red and black conductor. There is no green conductor. This is not the old "BX" cable with cloth conductors--this is more modern.

NEC 250.4(A)(5) and 250.4(B)(4):

Quote

...The earth shall not be used as the sole equipment grounding conductor or effective fault current path.

Does this mean that the cable can not be used for any new work? While I have no use for it right now, I would hate to toss it if it can possibly be used for something later on.

ThinkGood, if the cable is AC, shouldn't there be a bonding strip inside, that is in contact with the armor? Have you stripped back the armor to see if it is there?

The bonding strip is there.

I'd like to re-phrase the question some...I know that Type MC has an insulated green conductor for grounding. Does Type AC need a separate conductor for grounding to be compliant with the NEC (1999 and/or 2002), or is the metal armor sufficient?

I thought that the bonding strip is not to be used as a ground. If so, what does it do [Linked Image]

Am I about to get into the "grounding" vs. "ground" vs. "bonding" area? [Linked Image]

TG, the bonding strip inside type AC cable is there to reduce the reactance (resistance to alternating current) of the cable jacket. Without it, and under fault conditions, the jacket becomes a huge inductor which chokes the fault current, possibly preventing the OCPD from activating. Clear as mud?

Peter

Sure...an inductor...a duct that takes in the electrons, right? [Linked Image]

Thanks for the explanation.

Still curious, do current (pardon the pun) regs require a separate EGC?

The armor of AC Cable,(0NLY IN CONJUNCTION WITH THE INTERNAL BONDING STRIP), provides an adequate, low impedance, equipment grounding path.
This is not the case with MC cables of the interlocked (spiral wound) armor type. In that case, as CT said, the configuration of the armor will choke the fault current. Therefore, with common MC, the insulated grounding conductor is required to adequately serve as the EGC.

[This message has been edited by Redsy (edited 03-26-2003).]

Thanks again for the clarification!