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Romex Vs MC Cable (Things You Should Know)

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Last updated on August 14th, 2022 at 01:26 pm

Comparing the Romex cable and the MC cable is quite important to know. One key thing to note here is to consider the type of building you’re working on, whether for residential or commercial purposes.

In this article, we will critically analyze and look into the highs and lows of each of them. No doubt they are among the best options in the market presently. 

Although similar, they have different features, and they both use copper wire to carry Electricity and data.

While Romex cable carries a high-speed data network, MC cable carries a medium-speed network.

Romex and Mc cable are both approved for use for residential purposes by the National Electrical Code (NEC). They are widely used in the US and come in different wire gauges. Consider the benefits, features, differences, and quality to ensure that the cables are installed appropriately, safe for use, and last long. 

Mc Cable

Romex Vs. MC Cable

Metal-clad cable (MC), also known as BX cable Armored cable( AC) or Greenfield, is an insulated circuit gathered together in an enclosed armor of metallic sheath used for the passage of Electricity from one station to another in a building.

It is commonly used for commercial buildings and sometimes used for residential wiring. 

It is composed of plastic-coated insulated wires of about 12-14 gauge, stacked up together and covered with a metal sheathing with a twisted design. 

They can be buried underground with an outer metal casing, so attaching the cords to the metal casing is important. It has an insulated or bare full-size grounding conductor inside of it.

The cable has different types, for example, the MC intermediate and feeder cable with Aluminum armor, the MC lite isolated ground aluminum cable, etc. 

They can be installed both in an  Enclosed and open space and in an uncovered area. The outer casing is made of metal; hence it is strong and cannot be easily damaged.

It is mainly used in areas where the cable is outside, and it acts as its Electrical conduit and can run through concrete.

You should also check the local codes to know whether MC cable is authorized or not.

It is also used to carry Electricity in a data network. It is advised only to be used when required by the codes listed by the NEC.

#1. History

It is an ancient Electrical cable used as far back as the 19th century and is still used.

Listed in the NEC in 1903, It was one of the first cable types used for residential and commercial building construction.

It was named after its inventor, Harry Greenfield initially called Greenfield flexible steel armored conductor, and is still popularly known as Greenfield cable.

#2. Pros

  • Bx cables are highly durable 
  • They provide safety and protection
  • They are suitable for underground purposes
  • Use them in a moist place because they can resist corrosion.
  • They are waterproof and not prone to rust 
  • They have flexible metal conduit

#3. Cons

  • Bx cable is more expensive than Romex cable.
  • Due to its weight, it requires a certain level of expertise when Installing.
  • The cutting of the metal sheathing requires more strength and may take a longer period.

Romex Cable

Romex cable is a brand name of one of the best selling Electrical cables in the market today produced by Southwire. It is also called NM cable or SIM pull.

Its non-metallic plastic sheathing makes it user-friendly and easy to work with. The sheathing can withstand a temperature of 90 degrees Fahrenheit because of its ability to withstand heat. 

It has a 0.010 thick magnetic shielding alloy that is safe in any active electromagnetic device, reducing interference in telephone lines.

It is available in different types, and it’s in their colors white, red and black. The market price may be costlier than Mc cable because of its unique features. 

With its development In recent technology, it is best used for indoor purposes.

According to NEC, you need the conduit installation for Romex wire used in an outside location where the cable is exposed above the ground level.

It consists of wire, wire insulation, and outer cable. The wire has a metallic conductor that comprises 60-65% copper wire.

For the wire insulation, while the conductors are insulted in colors of red, white, and black, the ground wire is left bare or sometimes covered in green-colored PVC. 

The wires in the sheathing are also insulated in black. In addition, the outer covering of a Romex cable is made up of a thick PVC jacket that serves as a form of protection for the individual wire conductor. 

#1. History

It originated in Rome, New York, by the Rome wire company in 1922. It was listed in NEC in 1926 and has since been in operation under the trade name of Romex ®.

#2. Pros

  • It is cheaper to use than the BX cable.
  • The cable is made with plastic sheathing, making it easy to work with.
  • It is easy to straighten and remove with a plier.
  • The Non-metallic sheathing makes it lighter compared to the heavyweight metallic sheath.

#3. Cons

The major disadvantage is that you can’t use Romex cable wire in an outdoor environment or where the cable is exposed above the ground level and cannot be used underground.

#4. Similarities 

  • Both Romex and BX cables can function efficiently for indoor installation.
  • They both have plastic insulation for their copper wire.

#5. Differences

FactorsRomex cableMC cable
SheathingRomex cable is covered with a non-metallic coating.Mc cable is covered with a metallic coating.
InstallationYou cannot use it for underground installation except with a UF-B ground cable. Instead, use the Mc cable for underground installation with a conduit.
Exposed or EnclosedRomex should be installed in an enclosed environment for indoor use because it cant be used for outdoor applications.Because its cable provides adequate protection, it is best used in an exposed environment.
CuttingThe non-metallic covering is easier to rip off with a plier or a cable ripper. Ripping an Mc cable requires more energy because of its protective casing. It needs a specialized BX cutting tool or any other strong tool such as the hacksaw.
CostingRomex is cheaper to install.Mc cable is more expensive than Romex.
Safety & protectionThey have vinyl sheathing that can penetrate easilyThey have metallic sheaths that protect against accidental penetration. It is safer to use.

How to Remove the Outer Cable Of a Bx Cable?

The outer cable is made of a strong material that gives it strong protection from damage; hence ripping off may prove difficult however you can remove it manually or with cutting equipment. 

#1. To Remove Manually

You can cut the outer Bx armor manually by using a hacksaw. You must pay rapt attention when doing this not to damage the inner wire while trying to cut the metal sheathing.

#2. To Remove With a Cutting Tool

There is a specialized tool for cutting Bx armor cable. This tool makes ripping easier and safer, and it is also necessary to use when cutting a large number of cables as it makes work faster.

The Bx cutting Tool costs about $40-$50.Put the cable into its groove and turn the handle to cut out the metal sheathing. 


When selecting your option, check with the local authorities and NEC to know the type of electrical cables allowed in the area and the requirements for the length of cable that can go outside a junction box.

Finally, when using a BX cable, add a few meters to the normal measurements to cover the damage allowance.

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