Metal Clad Cable: Frequently Asked Questions

Metal clad cable (type MC cable) is any cable with a corrugated metal sheath or interlocking metal tape. The most popular MC cable uses three insulated wires and is available in a variety of gauges, with size 10 American Wire Gauge (AWG), 14 AWG, and 16 AWG being the most common options.

In this article, we’ll address several of the most frequently asked questions about metal clad cable. We’ll also explain how the right material handling equipment (MHE) can help contractors use MC cable efficiently — and greatly reduce electrical material loss.

What is metal clad cable used for?

MC cable is ideal for a variety of applications. It’s both flexible and durable — and significantly less expensive than conduit for most installations. With appropriate jacketing, MC cable can be used in wet areas, though installers must comply with local laws and ordinances.

Per the National Electric Code (NEC), metal clad cable cannot be used in locations that subject the cable to corrosive conditions. For example, MC cable can’t be buried directly in concrete.

With that said, MC cable is useful for service, branch, and feeder circuits. It cuts easily, installs easily, and eliminates the need for specialty bending and cutting tools.

Is metal clad cable the same as clad wire? 

No, clad wire (or "clad metal wire") is not the same thing as metal clad cable. As we’ve discussed, metal clad cable consists of conductors sheathed in metal guarding. It essentially provides cable and flexible metal conduit in a single package.

Clad metal wire, on the other hand, is a single conductor made of two types of metal, with one coating the other. For example, there’s copper clad steel wire, copper clad aluminum wire, and nickel clad copper wire.

Why blend two metals together to make a single wire? Because most electricity travels along the surface of the conductor. With a copper clad wire, you get the conductivity benefits of copper along with the strength, flexibility, or cost-saving benefits of another metal.

Metal clad cable is something else entirely — although you could conceivably find metal clad cable that incorporates clad metal wire as a conductor within the cable. In that case, you could say you’re using metal-clad, clad-metal-wire cable. 

What’s the difference between metal clad cable and armored cable?

The terms are sometimes used interchangeably, but armored cable (AC) typically does not have a standard ground wire. Instead, AC secures earth grounding via its metal sheath. 

Regardless of the metal (steel interlocked armor, aluminum armor, etc.), the sheath is suitable as the equipment grounding conductor (EGC) only if the product is UL-listed and identified for that purpose. If it's not designed to function as a ground, aluminum armor might lose conductivity over time. That's why, in most aluminum-armored electrical wiring systems, you'll find a dedicated grounding conductor, too.

AC cable's armor of interlocking metal tape is also less flexible than type MC, which makes it more appropriate for exposed applications that require additional physical protection. Depending on the product, AC cable has a reputation for having more grease on its armor.

What is stranded MC cable?

Stranded MC cable is MC cable where the insulated conductors are made of stranded wire instead of solid wire. Stranded conductors are made of lots of small wires twisted together (usually UL 44-compliant, THHN/THWN conductors). They're more flexible than solid copper wire conductors, particularly at larger sizes.

That makes stranded MC cable and metal clad armored cable a popular choice for residential and commercial electrical installations, in which insulated circuit conductors must make lots of twists and turns (and require defense against gnawing pests). 

Can MC cable be used outdoors?

Yes. The NEC specifically notes that metal clad cable is appropriate for outdoor use, although special considerations may be necessary; once again, MC cable must not be used in locations where corrosion or physical damage are possible. Outdoor metal clad cable may need to carry specific ratings and compliance features, such as water-proof wraps, sunlight resistance, or expanded temperature ranges.

Can MC cable be used for high-rise buildings?

The NEC permits the use of MC cables on buildings of any height, provided that the cable is properly secured and that other relevant code requirements are followed.

What’s the best way to cut metal clad cable? 

Many electricians section their MC cable the old-fashioned way: With diagonal cutters (or side-cutting pliers) — or even with a hacksaw. These methods work, although they come with some disadvantages. 

Here’s how to cut a metal cable sheath with diagonal cutting pliers: 

• Measure your cable to match the appropriate length. 

• Bend the cable around the spot you want to cut. Keep bending until the armor pops open. 

• Work your diagonal cutter into the opening, at a 90-degree angle to the armor’s open edge.

• Snip into the section of armor. Work your way around until the armor comes loose. 

Be careful not to cut or damage exposed wire as you clip the armor. And be aware that you’ll create a jagged edge. Even if you dull it with a metal file, it's best to use plastic anti-short bushings (which typically look like red inserts) to protect cables from spurs. 

Hacksaws don't make great cable cutters for the same reason: The saw blade increases the risk of damaging conductors too much. Either way, be sure to wear protective gloves.

Luckily, there is a better way to cut MC cable. Your best option for cutting cable armor without damaging conductors inside is to use armored cable rotary cutters. These roto cutters are essentially like can openers for MC cable armor. They safely cut the cladding without damaging conductors, and they’re the most ergonomic option, too.  

What’s the best way to store, transport, and pay out metal clad cable?

While metal clad cable is more cost effective than conduit, the savings are only realized when contractors are reasonably efficient. Material handling equipment (MHE) and storage equipment must be appropriate for the job — otherwise, working with MC isn’t necessarily a time-saver.

When selecting payout equipment, remember that MC cable is measured by wire gauge, not by the gauge of the sheath. For longer runs, consider options like the BHS Parallel Reel Wagon (PRW).

The PRW features heavy-duty steel construction, a two-way fork pocket design, and free-spinning compartments that provide even payout. It’s customizable and can accommodate up to 5,000 pounds of product — ideal for long-term storage or paralleling. 

The BHS Parallel Reel Payout (PRP) provides an even payout with free-spinning, multi-compartment reels, which can be customized as needed to pay out multiple types of cable on a single master unit. Individual hubs can be locked to prevent unwanted payout.

Other solutions to consider:

• The Reel Sherpa™Cradle (RSC-4K) protects heavy-duty wire and cable reels during transport and in storage. Capable of housing reels up to 55" wide and 52" deep, the Reel Sherpa Cradle features a 5,000-pound capacity and two-way fork pockets for easy transport.
• The BHS Wire Coil Cart (WCC) holds bulk loads of cable on wire. Removable steel posts simplify loading, and durable casters allow the unit to move easily when fully loaded. A carpeted base protects exposed ends of cable, and custom builds are available.
• BHS Wire Pull Carts (WPC) are all-steel units with fully adjustable shafts, which hold reels of up to 3,000 pounds. PVC wire guides ensure a smooth pull for payout applications. The WPC is also ideal for secure storage, and thanks to an integrated padlock hasp, strike protector, and steel doors.

Solus Group can help contractors and distributors find efficient, ergonomic options for any type of electrical installation. With virtually unlimited options for customization, we’re ready to discuss your next project.

Call Solus Group at 314-696-0200 to speak with a member of our team.