Anti-Short Bushings are not a NEC Requirement when Terminating Type MC Cable ...
Listed MC fittings do not require an additional anti-short bushing. Anti-short bushings that may be supplied by MC Cable manufacturers are for optional use by the installer, however they are not required. Fittings used with Type MC Cable are required to be listed per 330.40 of the NEC. The design of these fittings may or may not include an insulated throat however, they are required to be provided with a smooth, rounded end stop so that the metal sheath of the cable will not pass through and the wires will not be damaged in passing over the end stop.
The following is an excerpt from the Panel statement rejecting proposal ROP #7-116 from the May 2001 Report on Proposals (ROP) for the 2002 NEC. This proposal was seeking to require anti-short bushings on all MC Cable termination installations.
“Anti-short bushings are not required for Type MC cable in accordance with the listing for the product. The termination fittings approved for use with Type MC cables are designed such that the wires will not come in contact with the cut edge of the armor; the throat of the fitting is small enough to prevent contact with the armor. Type MC termination fittings perform the same function for Type MC cable as Type AC terminations plus the anti-short bushing do for Type AC cable.”
NACMA recommends that local Authorities Having Jurisdiction (AHJ) follow the requirements of NEC Section 330.40, Boxes and Fittings for MC Cable. Section 330.40 requires that the fitting be listed, but does not mandate the use of an anti-short bushing. Installers should check with the local AHJ to determine if anti-short bushings are required by the AHJ prior to installing MC cables.