Armored Fiber Optic Cable Grounding

tom baker

First Chief Moderator
Staff member
I have some Corning armored direct bury fiber optic cable, its about 1/2" OD. This is my first application of armored FO cable...what kind of bonding clamp do I need for the cable sheath?
I don't see anything in the Corning catalog
 

hbiss

EC, Westchester, New York NEC: 2014
Location
Hawthorne, New York NEC: 2014
Occupation
EC
Without seeing the cable I would say that the second of those shield bond clamps is what you need. I've used the first on copper cables many times which their video shows you how to do. I have never done fiber and there doesn't seem to be a video for it. I'm sure it's similar but the description talks about the strength members and there are extra parts.

It just might be that you can use the first one depending on your installation.

-Hal
 

gadfly56

Senior Member
Location
New Jersey
What’s likely to energize it. And if something did there is no effect to the optic strand. Is it just for rigidity?
Some of these are listed for indoor/outdoor, so you don't have a demarc box. You don't want something happening at building A to get to building B and vice versa.
 

hbiss

EC, Westchester, New York NEC: 2014
Location
Hawthorne, New York NEC: 2014
Occupation
EC
I've never seen armored FO cable so I can only surmise that it's there for physical protection. I do suppose that there are applications that have electronics at one or both ends that could use the armor for a ground path or bond.

-Hal
 

gadfly56

Senior Member
Location
New Jersey
I've never seen armored FO cable so I can only surmise that it's there for physical protection. I do suppose that there are applications that have electronics at one or both ends that could use the armor for a ground path or bond.

-Hal
See here for an example. A similar product is being used on a current project of ours.
 

hbiss

EC, Westchester, New York NEC: 2014
Location
Hawthorne, New York NEC: 2014
Occupation
EC
See where it say’s “requires no grounding or bonding”
The armor is not used for shielding so there is no need to ground for that aspect. If the cable is installed outdoors the NEC does not cover it. However, where it enters a building (or if it's run within a building) Article 770.93 applies which requires bonding of the metallic armor (or interruption of it) as close as possible to the point of entrance. So in that respect you kind of do have a "demarc" like copper or coax.

-Hal
 

kwired

Electron manager
Location
NE Nebraska
What’s likely to energize it. And if something did there is no effect to the optic strand. Is it just for rigidity?
I would say gives it a little rigidity, possibly some rodent resistance for direct bury applications, also is a conductive path that works great for connecting a locator when needed down the road.

The armor is not used for shielding so there is no need to ground for that aspect. If the cable is installed outdoors the NEC does not cover it. However, where it enters a building (or if it's run within a building) Article 770.93 applies which requires bonding of the metallic armor (or interruption of it) as close as possible to the point of entrance. So in that respect you kind of do have a "demarc" like copper or coax.

-Hal
I can agree with that.
 
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