timmermeier
Member
- Location
- alton il
- Occupation
- electrician
Their is a bare wire in ac cable it helps to ground the cable , why and how does it work, why not in mc cable ?????????????????????????????????????
I agree. You can use it to hold in the anti- short bushing but it's not required. I hate when guys wrap it around the armor.FWIW, it just need to be clipped (or some folks wrap it back around the cable). It does not terminate
Seen where it was terminated to the ground bar.I agree. You can use it to hold in the anti- short bushing but it's not required. I hate when guys wrap it around the armor.![]()
I've seen that too. Harry Homeowner doing his best work.Seen where it was terminated to the ground bar.
Seen where it was terminated to the ground bar.
I will confess I did that early on in my career. I was only a couple years in and didn't even know what AC cable was, it's not used in my area. Went down to Maryland to do some stuff for a friend of a friend.... It must be common there cuz Big Orange had it. I was like what the heck is with this little tiny puny EGC???? I didn't know what else to do but carefully terminated under a ground screwI've seen that too. Harry Homeowner doing his best work.
I actually don't understand the NEC's logic here. It seems like any armor or raceway should need to be an acceptable EGC. How is it ok for it to not be an acceptable EGC when it must serve as one for itself?In type MC cable, a full size wire EGC is present. The impedance of the armor doesn't need to be reduced.
With regular MC the EGC is the green or bare conductor. The armor just needs to be bonded via the connector because it's metal.I actually don't understand the NEC's logic here. It seems like any armor or raceway should need to be an acceptable EGC. How is it ok for it to not be an acceptable EGC when it must serve as one for itself?
Right, but if a fault occurs in the cable, from the ungrounded conductor to the armor, the armor needs to be an effective ground fault current path. Shouldn't it be required to be an acceptable egc? Why is it okay for that type of fault but not other types of faults?With regular MC the EGC is the green or bare conductor. The armor just needs to be bonded via the connector because it's metal.
I actually don't understand the NEC's logic here. It seems like any armor or raceway should need to be an acceptable EGC. How is it ok for it to not be an acceptable EGC when it must serve as one for itself?
I see your point. I guess that the thinking is that if a screw penetrated the cable it would somehow be close enough to a grounded cable connector which would open the OCPD. Maybe a 250' run of MC with a screw penetration right in the middle would not open the OCPD. Also if the installation involves MC cable often there is other grounded metal (steel beams, metal studs) involved that is in contact with the cable so collectively it seems to work.Right, but if a fault occurs in the cable, from the ungrounded conductor to the armor, the armor needs to be an effective ground fault current path. Shouldn't it be required to be an acceptable egc? Why is it okay for that type of fault but not other types of faults?