Does armored fiber optic cable need to be grounded? Yes!

How to bond and ground

Understanding how to bond and ground a fiber-optic system with armored cable can be confusing. First, it is important to understand the difference between the terms bonding and grounding. According to the NEC and industry standards, bonding is the permanent connection of metallic parts to form an electrical path that will be conductive and continuous. Grounding is the act of connecting that path to the earth or some conducting body that serves as the earth. When all the components of a system are properly bonded together and grounded to the earth, the risk associated with electrical current harming personnel or damaging property and equipment is reduced.

The first step is to connect/bond 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. Most cable manufacturers supply an insulated, UL-listed 6-AWG copper strand. The 6-AWG size is preferred for the bonding conductor because that allows it to comply with both the NEC and ANSI-J-STD-607. 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.

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

grounding armored fiber

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 (if present), or another accessible location per 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). The dedicated path can be a direct run or created by attaching to a rack or cabinet’s bonding system that bonds the rack or cabinet back to the TMGB or TGB. Specific requirements on how the TMGB or TGB are designed can be found in ANSI-J-STD-607 and other industry standards. When the armored cable is correctly bonded and grounded, it minimizes the risk of unwanted electrical current that could potentially harm personnel, property or equipment.

Props to Sara Chase with Corning Cable Systems.

Tight Buffered Fiber or Loose Tube Fiber

Overview – Tight-buffered cables are commonly used in intra-building, risers, general building, plenum environments and are more commonly installed indoors. TB fiber contains a thicker coating of material around the glass strand. Loose-Tube cables are more commonly installed outdoors, aerial, duct and direct burial installations. LT fiber contains multiple strands in a tube under a jacket, the strands are loose making outside forces harder to reach them and causing issues and is more durable.

Loose-Tube Cable LT fiber starts with 6 strands then to 12 and continues to climb in increments of 12 all the way up to 244 strands. They can be dielectric, more commonly installed for pole to pole installations and armored for direct burial installs. Each modular buffer tube holds up to 12 strands and this design makes it easier for drop-offs of fiber to intermediate points without bothering other modular buffer tubes. Colored buffer coat around the glass is size 250um. Modular buffer tubes are also color coded and add protection to the strands underneath. An optional filling compound or swellable tape will fight against water penetration for underground installations. For aerial, pole to pole installations excess fiber length (relative to buffer tube length) insulates fibers from stress of installation and environmental loading and tubes are surrounded by a dielectric or steel central member and serves as a anti-buckling element.

Let’s take a quick look at an armored loose tube fiber cable from our YouTube channel.

Tight-Buffered Cable – Tight buffered cables commonly consist of an overall jacket, strength yarns and strands of fiber. Fiber jumper patch cables is a good example and you’ve probably have handled these before and are commonly installed in racks when plugging equipment together. Multi-strand TB fiber is more common in premise local area networks. The colored buffer coat is 900um in size and helps to better protect fibers during handling in space constrained areas when routing and when terminating. The yarn tensile load also keeps the load away from the fiber.

Let’s take a quick look at an indoor/outdoor tight buffered cable.

Here’s another great video from our YouTube channel comparing the 250um buffer to the 900um buffer.

If you want to go further down the rabbit hole here’s a great video by the Fiber Optic Association doing an overview on fiber optic cable.

You should have enough to chew on, we have a ton of fiber optic videos on YouTube if your interested.

Comment below and don’t forget to share! Thanks.

When and where to use Category 5E crossconnect cable

If your looking for crossconnect cable Mercy gives us a quick look at why use a Cat5e.

After reviewing this video I’m sure your thinking why ever use Cat3 again, maybe make some figurines?

cross connect guy cross connect wire man

Comtran Cable now available at Discount-Low-Voltage.com

Do you have a project where an American made wire is your only solution? Comtran is a good fit for your project.

They also manufacture many audio, fire alarm, security and specialty electronic cables. I’m sure they’ll have a fit for you.