Question: MC cable
I have heard there is a new type of MC cable with a bare aluminum grounding conductor. Is the sheath itself suitable for grounding? Is it Listed? Are there any Listed MC cable connectors for use with this cable?
Answer
There is a new type of MC cable for use in dry locations only, that is of the interlocked metal tape–type. It is constructed with a bare aluminum grounding/bonding conductor that is sandwiched between the Mylar wrap around the conductors and the interlocked metal tape armor. That construction ensures intimate metal contact of the grounding/bonding conductor and the metal armor sheath of the cable. The construction looks similar to a type AC cable construction, however, the grounding/bonding conductor is full-sized and is tested to assure that the sheath/grounding/bonding conductor is capable of performing as a full-size equipment grounding conductor in accordance with NEC 250.118 (10)(a) with or without the grounding/bonding conductor terminated to a grounding point. That means the cable can be installed with the grounding/bonding conductor clipped off at the end of the sheath or terminated to a grounding point. This type of cable can be identified by the marking “Armor is equipment grounding path component” located on the marker tape or the outer jacket, and on each grounded circuit conductor.
There are metal-clad cable connectors that have been Listed for use on this type of MC cable. They are identified on the fitting or carton or both as suitable for use with this type of cable by the marking that states “MCI-A,” or “Metal-Clad Interlocking Armored Ground Cable Type.”
This cable is Listed under the product category Metal Clad Cable (PJAZ). The cable connectors are Listed under the product category Metal Clad Cable Connectors (PJOX). The Guide Information for PJAZ is located on page 79 in the 2005 General Information for Electrical Equipment Directory (the White Book) and the Guide Information for PJOX is on page 80, or by entering PJAZ or PJOX at the Category Code search on UL’s Online Certification Directory located at www.ul.com/database.
