How to Install Armored Fiber Optic Cable

Armored fiber optic cables are designed to provide extra mechanical protection for the inner fiber. They employed two types of cable housing to prevent damage; one is interlocking armor and the other is corrugated armor. The former is an aluminum armor that is spirally wrapped around the cable and it is applied in indoor and indoor/outdoor cables. It offers superior durability and resistance to extrusion. The latter is a coated steel strip that is folded longitudinally around the cable. It is generally used in outdoor cables and offers extra mechanical and rodent protection. You may be very familiar to installing standard fiber optic cable. But armored fiber optic cable installation is very different. This article will explain how to install armored fiber optic cable and the things that should be noticed in splice.

Merits and Defects of Installing Armored Fiber Optic Cable

Installing armored fiber optic cable can bring benefits to the network system but it also has some shortcomings in practice.

During some indoor and outdoor installations, there is a need to provide added mechanical protection for the cable due to the harsh installation environment. For example, underground cabling in rocky soil or in buildings with congested pathways where fiber cables may be crushed. Installing an armored fiber optic cable in these cases would provide extra protection to the optical fiber and added reliability for the network, reducing the risk of downtime and cable damage due to rodents, construction, moisture and other factors.

However, installing interlocking or corrugated armored cable has the inconvenience that bonding and grounding is required. This inconvenience can be removed by using an dielectric armored cable, which can provide the desired protection like any armored cables and calls for no bonding and grounding of the armor, or extra steps of installing a conduit and cable when the cable has no armored protection. But the dielectric armored cable is more costly than metallic armored cable or cable conduit.

interlocking, corrugated and dielectric armored cables

Steps of Installing Armored Fiber Optic Cable

The key to knowing the steps of installing armored fiber optic cable is to know how to correctly bond and ground the armor. Since the metallic components (interlocking and corrugated armor) of the cable is conductive, proper bonding and grounding is required for the dissipation of unwanted electrical current so as to effectively ensure personal and site safety.

The first step is to connect the cable armor to a bonding or grounding electrode conductor. This can be accomplished right after the cable is accessed, and the armor is exposed. A bonding conductor or jumper is a short length of conductor, such as copper wire, that maintains electrical conductivity between two metal objects. The bonding conductor is required to be UL-listed and made of either copper or another corrosion-resistant conductive metal. This stranded or solid wire can be insulated, covered or bare. The bonding conductor can be attached to the armor by the use of a listed clamp, lug or connector, as stated in NEC Article 250.70.

bonding and grounding tools

Once the clamp is installed, vinyl tape can be tied around the clamp and exposed armor to protect the installer and the fiber from any sharp edges where the armor is exposed.

For the conductive fiber-optic cable to be fully grounded, the bonding conductor from the cable needs to be bonded to the intersystem bonding termination, or another accessible location according to NEC Article 770.100. The intersystem bonding termination is the device that connects the bonding conductors to the building’s grounding electrode and ultimately to earth. Typically this is accomplished by connecting the bonding conductor to a dedicated path back to the telecommunications main grounding busbar (TMGB) or the telecommunications grounding busbar (TGB). When the armored cable is correctly bonded and grounded, it minimizes the risk of unwanted electrical current that could potentially harm workers, property or equipment.

Things to Concern in Splicing Armored Optical Cable

Since the armored cable is different from common fiber optic cables in that a stainless steel armor is inside the cable jacket and outside the optical fiber, it has special requirements during splice. Some tests and measurements should be made to ensure that the armor of fiber optic cable is continuous.There are two areas of concern. The first is armor bonding within a splice and the second is armor continuity between splices. We should pay attention to these two aspects to accomplish a good splice of armored cables.


Armored fiber optic cable brings benefits in providing solid protection to the cable and thus the network. Knowing how to bond and ground the metallic armor is very important in safely installing this type of cable. Also to ensure the armor continuity during splice is essential to keep the high performance of armored fiber optic cable.

Cabling Solutions for 100G QSFP28 Transceiver

Since the demand for high speed data transmission keeps growing, 100G Ethernet has been widely deployed in data center. Designed for high port density with small compact size and low power consumption, 100G QSFP28 transceivers domain the 100G transceiver module market. In the previous post “Focus on 100G QSFP28 Transceiver”, I have introduced four 100G QSFP28 transceiver types—100GBASE-SR4 QSFP28 transceiver, 100GBASE-PSM4 QSFP28 transceiver, 100GBASE-CWDM4 QSFP28 transceiver and 100GBASE-LR4 QSFP28 transceiver. So in this article, I will share cabling solutions for 100G QSFP28 transceiver with you.

We know that the above four 100G QSFP28 transceiver types can be divided into two categories according to the interface: 100GBASE-SR4 QSFP28 and 100GBASE-PSM4 QSFP28 are with MTP/MPO interface, while 100GBASE-CWDM4 QSFP28 and 100GBASE-LR4 QSFP28 are with duplex LC interface (shown as the figure below). Therefore, the cabling solutions are different respectively.

100G QSFP28 transceiver

Cabling Solution for 100G QSFP28 with MTP/MPO Interface

This kind of 100G QSFP28 transceiver is usually used with 100g MPO cable. For example, 100GBASE-SR4 QSFP28 can support 100G optical links over eight fibers and it can be connected with a 12-fiber MTP/MPO patch cable (four fibers for transmit, four fiber for receiver, leaving four fiber unused). Similar to 100GBASE-SR4 QSFP28, 100GBASE-PSM4 QSFP28 is also used with 12-fiber MTP/MPO patch cable. However, 100GBASE-SR4 QSFP28 utilizes multimode cable for 100 meters data transmission distance while 100GBASE-PSM4 QSFP28 utilizes single-mode cable for 500 meters optical links. Take 100GBASE-SR4 QSFP28 for example, the following figure shows that two 100GBASE-SR4 QSFP28 transceivers are connected with a multimode 12-fiber MTP trunk cable.

Cabling Solutions for 100GBASE-SR4 QSFP28 Transceiver

The following figure shows that with the use of multimode MTP-LC 8f fanout patch cord, one 100GBASE-SR4 QSFP28 transceiver can be connected with four 25GBASE-SR SFP28 transceivers.

100GBASE-SR4 with four 25GBASE-SR SFP28

Cabling Solution for 100G QSFP28 with Duplex LC Interface

Structured with duplex LC interface, 100GBASE-CWDM4 QSFP28 and 100GBASE-LR4 QSFP28 are usually used with single-mode patch cables with LC duplex connectors. When upgrading the network, we often meet the problem that we have to replace all the fiber patch cables. However, you do not have to worry about this issue if your transceivers are 100GBASE-CWDM4 QSFP28 and 100GBASE-LR4 QSFP28. Common single-mode duplex LC patch cable can meet the cabling requirement of these two transceivers. The following figure shows that two 100GBASE-CWDM4 QSFP28 transceivers are connected with a single-mode duplex LC patch cable.

Cabling Solutions for 100GBASE-CWDM4 QSFP28 Transceiver


For 100G QSFP28 with MTP/MPO interface, you can choose MTP/MPO cable, but remember that 100GBASE-SR4 QSFP28 utilizes multimode cable while 100GBASE-PSM4 QSFP28 utilizes single-mode cable; for 100G QSFP28 with duplex LC interface, you can use duplex LC patch cable for long distance transmission. I hope after reading this article, you can get something helpful. The transceivers and fiber optic cables mentioned above can be found at FS.COM. For more details, you can visit our site.