Old-style armored cable (Type AC) is still made and widely distributed. Why is this, given that type MC cable is more versatile (more conductor configurations, more Code-permitted applications) than type AC cable by far, and the new type MCI-A products coming out eliminate any edge AC may have had in termination labor? I'd have thought type AC would be utterly obsolete now, replaced in all new work and rework by type MC. Are there applications where AC can be used but MC (especially MCI-A) can't?

(For those who haven't kept up -- MCI-A is a type of MC cable that uses a bonding means consisting of a full sized aluminum ground wire integral with the corrugated, spiral wrapped armor, usually aluminum as well. It is available through multiple manufacturers -- Encore calls it SmartGround or MC-SG, Atkore/AFC calls it MC-Quik, and Southwire calls it MCAP.)

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    Never underestimate the power of inertia and tradition to trump ration and reason. It's why we most often still call tissue paper a Kleenex, still write dates in that irrational and ambiguous 3/4/16 notation, use AM and PM instead of a 24 hour notation, and use non-SI measurement systems. – AndyW Jun 26 '16 at 17:35
  • In some local areas the ground must be copper, in my area over 15a can not be used without a ground , I.E.- metal clad 12-2 can not be used in exposed areas where 12-3 can be used. Because of the metal some places like cargo trailers it is easier to run exposed where nm of any type is not allowed. – Ed Beal Jun 26 '16 at 21:21
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    What is the price difference? Never underestimate the power of the dollar. If you are just doing a strip mall then AC may be more cost effective. If you are doing the patient area in a hospital then MC may be the way to go. Good info on differences here: afcweb.com/installation/mc-ac-cables-installation – ArchonOSX Jun 27 '16 at 0:11
  • @ArchonOSX -- actually, the two differ rather little in cost... – ThreePhaseEel Jun 27 '16 at 0:29
  • I only know is specs on AC shows the difference being that it has Moisture-Resistant, Flame-Retardant Paper where as the MC does not. – spicetraders Sep 23 '16 at 19:32

People could use the older style cable for things like low voltage control lines to industrial machinery. Or in place where the metal is just used as protection for the wiring not as a conductor. Or maybe in repairing old systems. I;m sure there are a lot more uses other than its original purpose.

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