If diamonds are a girl’s best friend, then metal clad (MC) cable might just be an electrician’s partner of choice.

Metal clad cables can be found in many locations, including indoors, outside, and even underground. This cable is durable and flexible, making it an excellent choice for service, feeder, and branch circuits and across commercial, industrial, and residential applications.

Type MC cables work well in Class I, Division I hazardous locations (these are called MC-HL cables), healthcare facilities, theaters, assembly plants, and power and lighting control. Despite its aluminum armor, it can also be used in wet locations but needs to have a PVC jacket for protection. A list of potential applications is outlined in National Electrical Code (NEC) Article 330.

For most applications, the typical MC cable will range from #14 to #10 AWG but can be as large as 2,000 MCM in some cases.

The Types of MC Cable

According to the NEC, a metal clad cable is “a cable in which the conductors are enclosed in a corrugated metal sheath or interlocking metal tape, insulated, and the entire cable is put together at the factory.”

It can include one or more insulated conductors, including one full-size ground wire, and features one of several types of armor sheathing.

  • Aluminum Interlocked Armor (AIA) – This spirally-would cable is used in industrial applications, including pulp and paper, chemicals, mining operations, and power. AIA, when jacketed with PVC, is flame-retardant, impervious to water, and sunlight resistant, and is best suited for utility and industrial areas where there is a potential risk of high-heat or fire, and in tight spaces.
  • Continuously Corrugated Copper Weld (CLX) – This medium-voltage cabling is used for controls, instrumentation, and other low-voltage applications. The corrugated metal sheath can be made from aluminum, copper, steel, or bronze, and has a wavy look to it. CLX cable is impervious to water, and has uses in petro-chemical, transportation, pulp and paper, and high-tech applications.
  • Steel Wire Armor (SWA) – Also known as Served Wire Armor, this cable armor uses strands of served galvanized steel wire. It is typically used for underground applications and in power and auxiliary control cable installations.
  • Galvanized Armor – This metal clad cable is protected by galvanized steel and a PVC jacket, making it well-suited for wet and oily applications. It is direct burial rated and can be used in mining, pulp and paper, and petroleum.
  • Teck90 – Teck90 cable has smooth aluminum armor, and can be used in industrial applications, including petro-chemical. It’s impervious to water, sunlight resistant, direct burial rated, and can be installed in hazardous environments.

Once you’ve selected your armor type, you’ll also have to determine what voltage the application will require. Manufacturers use different jacket colors to differentiate MC cables from one another, including:

  • Black – 600v applications
  • Yellow – 5kv applications
  • Red – 15kv applications

Why Do Electricians Use Metal Clad Cable?

Metal clad cable is durable, flexible, and ready to use as soon as it reaches the job site. As a result, it’s an excellent choice for electricians who want to save time and reduce labor hours.

The armored cable has a flexible casing, making it easier to bend around corners and fit into tight or concealed spaces. It also protects internal conductors from fire, prevents damage due to abrasion or impact, provides environmental protection from wildlife and weather, and can block out some electromagnetic interference.

Another reason MC cable is so popular with electricians is that it doesn’t need a conduit. Unlike cables that need to be lubricated and pulled through winding conduit pathways, metal clad cable only needs to be supported every few feet. This can be done using a cable tray or staples, cable ties, straps, or hangers. Without conduit to worry about, installers save tons of time running MC cable because it essentially does the same thing.

Remember, metal clad cables can only be used with metal electrical boxes! Other box types like fiberglass or plastic won’t work because they aren’t designed for that use and will fail an electrical inspection. According to NEC guidelines, the reason is that there is no way to maintain the electrical continuity of the effective ground-fault current path.

Is MC Cable the Same as AC Cable?

With a naked eye, it’s tough to tell the difference between a metal clad cable and a standard armored cable. However, as my mother always tells me, “It’s what’s on the inside that counts.”

The standard AC cable includes:

  • A metal jacket and wire or a thin strip to ensure proper grounding
  • Insulated conductors wrapped with paper.
  • Up to 4 phases and neutral conductors
  • Sizing from #14 to #1 AWG with a smaller bond wire
  • No protection for wet environments

A standard MC cable includes:

  • A metal jacket surrounding one or more insulated conductors
  • A PVC jacket for direct burial and wet location application
  • A full-size ground wire (unlike AC, MC armor cannot be used for grounding)
  • Can range in size from #18 AWG to large feeder sizes

Faster Installations, Fewer Costs

When everything is contained within one cable, it makes sense why electricians choose to work with MC cable when they have the chance.

It’s a cost-effective, time-saving product that works in multiple locations and doesn’t have the same limitations associated with products that need to be pulled through conduit. Thanks to its flexibility, it can bend easier than conduit installations and fit into tight spots and concealed areas more safely.

For crews, that means less time spent pulling wire, fewer workers needed to get the job done, and cleaner installations.

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