Armored cables and normal cables both transmit electrical signals, but they have key structural differences that impact their performance. While armored cables provide superior mechanical protection against impacts, abrasion, and chemicals, this comes at a higher material and installation cost compared to normal cables.
In this article, we’ll explore the key differences between armored and unarmored cables, including their structure, level of protection, typical applications, cost, and installation considerations.
What Is Armored Cable
Armored cable, also known as Type AC (Armored Cable) or BX cable, is an electrical cable that features a flexible metal armor surrounding the conductors. This armor, typically made of interlocking aluminum or steel strips, provides mechanical protection and additional grounding for the cable. The cable’s construction includes insulated phase conductors, a bare ground wire, and a bonding strip or wire, all encased within the metal armor.
What Is Normal Cable
Normal cable, or unarmored cable, refers to electrical cables that do not have the additional layer of metal armor. These cables, such as Non-Metallic Sheathed (NM) cable or Romex, consist of insulated conductors and a bare ground wire wrapped in a protective plastic sheathing.
Key Differences Between Armored and Normal (Unarmored) Cables
Structure
Armored cables have an additional layer of flexible metal armor that surrounds the insulated conductors and bare ground wire. This armor provides extra protection against physical damage and electromagnetic interference (EMI).
Normal cables rely on the outer plastic sheathing to protect the conductors from minor damage and environmental factors.
Protection
Armored cables offer superior protection compared to normal cables due to the metal armor. The interlocking metal strips protect the conductors from impact, abrasion, and crushing forces. This makes armored cables suitable for installations where the cable may be exposed to mechanical stresses, such as in industrial settings or when running through walls or floors.
Normal cables, while still durable, do not provide the same level of protection against physical damage.
Applications
Armored cables are commonly used in commercial and industrial settings, such as factories, warehouses, and construction sites, where the cables may be subject to mechanical stress or where additional grounding is required. They are also suitable for outdoor installations and underground burial.
Normal cables, like NM cable, are primarily used in residential wiring applications. They are the standard choice for running electrical circuits within walls, floors, and ceilings of homes. NM cables are also used in light commercial settings where the cables are not exposed to excessive mechanical stress or harsh environmental conditions.
Cost
Armored cables are generally more expensive than normal cables due to the additional materials and manufacturing processes required to produce the metal armor.
Normal cables, being simpler in construction, are more affordable and widely used in residential and light commercial applications where the added protection of armored cables may not be necessary.
Installation
Installing armored cables requires specialized tools and techniques compared to normal cables. The metal armor needs to be stripped back, and the cable must be securely fastened and grounded using appropriate connectors and clamps. Armored cables are also heavier and less flexible than normal cables, which can make them more challenging to work with in tight spaces or when making bends.
Normal cables, such as NM cable, are easier to install and require fewer specialized tools. The outer sheathing can be easily stripped, and the conductors can be connected using standard wire nuts or connectors. NM cables are more flexible and lighter, making them easier to route through walls and around obstacles.