Armored cable is an alternative to running conduit in difficult locations. Instead of running rigid metal pipe that has to be screwed together in twisting or tight locations, it is often easier just to thread flexible armored cable into place. Armored cable comes rolled in spools like regular cable, and is typically available with two, three, or four individually insulated conductors in a variety of sizes1.
Armored Fiber Optic Cable is used by the military, industrial applications as in petrochemical, industrial plants including nuclear and utilities are installed by direct burial in areas where rodents are a problem. The armored construction provides additional crush and rodent protection, and this means the armored cable is conductive, so it must be grounded properly.
There are three basic types of metal-covered cable; all are referred to as armored cable. BX is the oldest form. This cable type went into production during World War II and saw heavy use for several years. While this cable provided the protections common in armored cable, it had a tendency to leak, and its grounding system was poor.
True armored cable is essentially just a heavier form of BX. It features a better grounding system and a heavier internal insulation. The process used to cover the cable in its metal covering allows for better waterproofing and an overall tougher design.
The last style of armored cable is metal-clad (MC) cable. MC cable uses a different grounding system from true armor cable and may have additional waterproofing. This is the newest type of metal-covered cable and is found in a wide range of commercial and industrial buildings.
It comes preloaded with wires already in it so you don’t have to fish them through yourself.
It provides its own ground bonding.
It can be run in places ordinary conduit cannot.
It provides a great deal of protection from damage by screws or nails as compared to ordinary insulated cable.
The freshly cut edges are difficult to work with and very sharp.
New wires cannot be run through it.
It is expensive, and a new cutting tool must be bought for each new size.