article 518 ques

[wireman1]

does the metal jacket of mc cable have to qualify as a equipment ground plus carry a insulated grounding conductor in side the mc cable or is the insulated ground sufficant

 

[roger]

The insulated EGC wire complies with 518.4(A).

Roger

 

[augie47]

If I'm not mistaken, it would depend on the type MC cable being used. The interlocked metal tape type MC requires the equipment grounding conductor for it to be a qualified 250.118 ground.
The smooth or corrugated MC having a bonding wire can qualify as a 250.118 equipment ground.
As I read 518.4, either would be allowed. (Unlike 517,13)

 

[hbiss]

does the metal jacket of mc cable have to qualify as a equipment ground plus carry a insulated grounding conductor in side the mc cable or is the insulated ground sufficant

The armor of MC cable cannot be used as an equipment ground, though it must be grounded. That is why there is a separate insulated green or uninsulated bonding conductor. The green would be wired just like the ground if you were doing Romex. The uninsulated version usually gets clipped off flush with the end of the armor and installed like AC cable.

-Hal

 

[david]

The armor of MC cable cannot be used as an equipment ground, though it must be grounded. That is why there is a separate insulated green or uninsulated bonding conductor. The green would be wired just like the ground if you were doing Romex. The uninsulated version usually gets clipped off flush with the end of the armor and installed like AC cable.

-Hal

The armor of MC cable cannot be used as an equipment ground, though it must be grounded.

That is why there is a separate insulated green or uninsulated bonding conductor.

if the metal ("tape") sheath type cable has a bonding conductor bonding the metal sheath than the metal sheath qualifies as an equipment ground

 

[jbelectric777]

mc verse bx

mc verse bx

ok - touchy subject and the least understood - bx with the bonding wire is approved as an egc mc however is not listed as an egc maybe because of manufacture mc has a full size grounding conductor and its not nor ever has been approved for egc re read that article so you don't install a thousand feet just to have it knocked down - if a fault occurs in the metal sheath it will trip its ocpd fast because mc's ground is connected to everything:lol:

 

[roger]

The question is not whether one type of cable is recognized as an EGC per 250.118, the question is if article 518 requires the sheath itself to be recognized as an EGC (like 517.13(A) does) which it doesn't, once again see 518.4(A). If an insulated EGC is present that is all that is required.

Roger

 

[kwired]

I never fully understood the difference between these two products, especially when both commonly had same/very similar aluminum interlocking sheath for the past 30 or so years. I understood the bond wire within AC allowed for using the sheath for EGC, but more recently they come up with MC AP (I believe that is Southwire product, others may have something similar) that has similar bond wire and no separate EGC, unless you get the "healthcare cable", but there supposedly is still something different between them and though they can both be used in many places, there are some places you can use one but not the other.