Article 330.10 of the NEC lists 12 general uses and four specific uses for MC cable. Let's take a closer look at where each type of product can and can't be applied. MC cable and EMT share other traits as well, most notably in uses permitted/not permitted as noted in the NEC. Also, like the metal sheath of MC cable, the raceway provides supplementary and redundant grounding and greatly lowers the overall impedance of the equipment grounding conductor. In fact, the sections of raceway on either side of a single break would still be grounded from opposite ends of the run.

Then, if the raceway were to pull apart under unforeseen conditions, ground continuity for the circuit would not be lost. However, most electricians still opt to “pull a green for everything.” This raceway, with appropriate fittings properly terminated, can serve as an equipment grounding conductor in most applications. The raceway is typically made of steel with a smooth galvanized finish, or aluminum. In the discussion that follows, we will consider the most commonly used MC cable, interlocking metal tape aluminum sheath with solid copper conductors, primarily 12-2 w/ground and 12-3 w/ground used extensively for branch circuit work.ĮMT is an unthreaded thinwall raceway that is commonly seen in industrial and commercial locations. Conductors are copper, aluminum, or copper-clad aluminum (solid or stranded). MC cable comes in various versions such as with corrugated copper armor or with an outer supplementary corrosion-resistant material. The metal jacket serves to supplement the equipment grounding conductor since it is firmly clamped to grounded metal enclosures at both ends - so that the unit cannot become energized without instantly causing the overcurrent device to trip out. MC cable contains an insulated grounding conductor which, when properly terminated at both ends, makes a reliable return path for fault current, enabling the overcurrent device to perform its protective role. Therefore, the outer sheath of MC cable does not qualify as an equipment grounding conductor. Whereas armored cable has a grounding strip in intimate contact with the inside of the metallic sheath, which can then serve as the equipment grounding conductor, MC cable has no such strip.

Although MC resembles its close relative, armored cable, there are some distinct differences. To do so most effectively, it's important to understand specific construction specifications and permitted uses for each system, but first let's begin with some basic definitions.ĭefinitions. Therefore, on any given job, it's advantageous for electricians to use both types in concert. When used with appropriate conductors, metal-clad (MC) cable and electrical metallic tubing (EMT) have nearly identical uses but quite different working characteristics.

Emt to mc connector