Anti-shorts required?

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ssandoval

ssandoval

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League City,TX
Can someone please tell me where it says in the NEC that you must use an anti-short with MC? In Art 320.40 it is very specific but that for AC cable. Is all MC cable inherently AC cable also? The stuff we use is marked MC. By the way, what's the difference between AC and MC?
 
There is no NEC requirement that you use anti-short bushings on MC cable only on AC cable.

The biggest difference between standard MC cable and AC cable is that the sheath of MC cable can't be used as a EGC and MC cable has an insulated EGC.

The sheath of AC cable can be used as an EGC because there is a small aluminum bonding strip installed in contact with the inside of the sheath to provide a low impedance fault current path.

Chris
 
ssandoval said:
Can someone please tell me where it says in the NEC that you must use an anti-short with MC? In Art 320.40 it is very specific but that for AC cable. Is all MC cable inherently AC cable also? The stuff we use is marked MC. By the way, what's the difference between AC and MC?
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you may want to just search the threads for that questions...there are lots of discussions regarding this.
 
Would suggest you all either bookmark or print this link as I carry it folded in my code book. I show more people this NEMA Bulletin than anything else I carry.
 
dcspector said:
Then use a listed AC cable connector when you run out:grin:
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Actually that would be bad unless the AC connector was also listed for MC cable.:)

Straight AC connectors don't neccessarly have the intergral bushing that an MC connector does. That is the reason that MC cable does not require additional anti-short bushings, due to the fact that the listed fittings all have a bushing.

Chris
 
raider1 said:
Actually that would be bad unless the AC connector was also listed for MC cable.:)

Straight AC connectors don't necessarily have the integral bushing that an MC connector does. That is the reason that MC cable does not require additional anti-short bushings, due to the fact that the listed fittings all have a bushing.

Chris
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Chris,

Are you sure about that? Take a look at Chris Kennedy's link.
 
I asked the Armored Cable Mfgs code rep, Phil Simmons, about this issue. The reason why its confusing is the connectors come with red heads and the bags are attached to the MC or AC cables when sold (at least the ones I see locally). He said the mfgs are considering changing this practice. The difference between MC and AC cable is "paper or plastic". Well actually MC is the newer product, and with MC-AP available, its getting even more of the market share.
 
I was told never to use anti-shorts with the new MC-Ap. if the anti short was placed in and the alum ground wire was inside the anti short and the ground was cut without bending to over before cutting, as instructed, this could result in a poor bond. Something to think about.
 
jmargolis79 said:
I was told never to use anti-shorts with the new MC-Ap. if the anti short was placed in and the alum ground wire was inside the anti short and the ground was cut without bending to over before cutting, as instructed, this could result in a poor bond. Something to think about.
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We have yet to use much MC-ap, is this a recommendation or a requirement?
 
jmargolis79 said:
I was told never to use anti-shorts with the new MC-Ap. if the anti short was placed in and the alum ground wire was inside the anti short and the ground was cut without bending to over before cutting, as instructed, this could result in a poor bond. Something to think about.
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Check the instructions. You cut the aluminum bond flush with the end of the jacket, you dont bend it over.
 
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