Armoured Cable Vs. Unarmoured Cable: What's The Difference?

Structure
Many people may think that armoured cable just has metal protection. To be precise, the armoring material doesn't have to be metal, it can be fiber yarn, glass yarn, polyethylene etc. The only thing that makes armored cable different from unarmored cable is that the former has an additional outer protective layer for optical cable. The 4 core armoured cable tends to be more expensive than unarmored cable, while the armoured cable with steel strip and aluminum is much cheaper than armored fiber cable with Kevlar, which is usually used for special occasions.

Application
Armoured cable is installed in locations exposed to mechanical damage, such as on the outsides of walls, as an alternative to conduit. Armoured cable usually has a small metal ribbon to ensure electrical continuity of the safety ground. (You must run a separate ground wire in flexible conduit too; you can't depend on the continuity of the conduit.) In HT & LT distribution, 4 core armoured cable is preferred. Inside walls and in other protected locations, less expensive unarmored electrical cable can be installed instead. Unarmoured cable is mainly used for control systems.

Why Should Use Armoured Cable Over Unarmoured Cable?
There are a couple of reasons that armoured cable should be used. The biggest reason is about strength, because armored cable was used more extensively in past decades when cable was simply directly buried under dirt and not used through a conduit. Nowadays most local municipalities require conduits to be trenched in prior to installing network components, thus eliminating the need for unarmored cable in most applications. Secondly, rodents or animals can and will chew through cables so the armor protects the cables from damage by animal or shoveling in direct bury applications. Thirdly, the most uncommon reason it would be used is in an RF environment that has an off air RF signal that is powerful enough to interfere with your network, the armor when grounded can provide another layer of RF protection.

Conclusion
Armoured cable can be regarded as a kind of strengthened cable, which is harder and stronger than standard optical cable. With an unparalleled protection against physical damage without sacrificing flexibility or functionality within fiber networks, 4 core armored cable is a perfect addition to any fiber network in hazardous environments.