Trenching for Telecommunication Cable and Fiber Optic

No doubt that trenching for direct burial cable is hard work but before you get to that you might what to know what method is best for you. Let's get into the 3 methods used for trenching.

First we have your hand dig method and this is used when there is not enough room for machinery or when extra precautions and care must be used to avoid an obstacle.

Here's an example of the hand dig method in action from YouTube.



Your second method is using a backhoe. A trencher might not be accessible in certain areas of your property. Now let's check out a backhoe in action.



When your cable route is open and free from obstacles a trencher is the preferred method for trenching. Smaller trenchers and walk behind types are typically used for small diameter cable installations and short cable runs, larger trenchers are of course for larger cable installations.




Depending on the method you decide to use, trench width can range from 3 inches to 24 inches and up to 7.5 feet deep. Don't forget to check out your Frost Depth Line.

Small cables may be installed using a less cumbersome machine that can be controlled by an individual walking behind it and readily avoiding obstructions. While some machines have limited use for long runs or large sizes of cables, it may be effective in placing smaller lateral cables or service wires. Many different machines are available, and your OSP installation should be focused on determining the best route and not the machinery for cable placement.

"By Mercy Salinas"

Network cable qualification tester vs. certification tester

I get sucked into this discussion constantly and it always ends up being a long conversation that goes round and round and ends up going nowhere.

Our good buddy Ron with Ideal Industries discusses the differences of a qualifier vs certifier when the quality of your network cabling is in question.


Did you notice the standards chart did not include "Cat5 Big E" or "Cat5e 350mhz"? Did you find a standard for "Cat6E"? Those are probably topics that you'll have to educate your customer on.

Questions, comments? Leave them below.

"By Mercy Salinas"   

What's my frost depth line for OSP copper and fiber cable?

In one of our previous blog post we talked about the burial depth of your copper and fiber cable, how copper cable should be at a minimum of 24 inches and how fiber should be at a minimum of 1 meter. Let's dig more into the attached term "Minimum" and how the frost line in your area will change that.

The frost line is the depth to which water in the soil will freeze in the winter. You should know this before you lay your cable down, water expands as it freezes and will cause damage to your communications investment.

The frost line will vary depending on your location and can range from 3 to 6 feet. An easy way to determine your line is by examining a frost line map.

National frost depth maps are only a reference, you should check with your local building inspector for a more accurate measurement for your area.

I hope this has shed some more light into the "Minimum" term of your burial cable depth. Measure twice cut once!

Any other questions? Comments? Leave them below.

"By Mercy Salinas"

How deep should you bury your copper feeder cable, fiber cable?

One of the most common questions we get is "How deep am I going to bury this wire" when it comes to our outside plant copper PE89 cable and outside plant fiber optic cable. Let's find out.

Most OSP cable runs are never as easy as digging a trench, lay cable, done. Your burial depth will be affected by a number of things, for example:

- Crossing under railroad tacks, under roads and highways

- Lakes, ponds and rivers

- Natural obstacles like rocks and trees

- Outside industrial locations with possible soil contamination

- The Frost Depth Line for your location

Now that your thinking about your entire run a bit more, your copper cable should be placed at a minimum depth of 24 inches (610 mm). However, don't only think about what obstacles are in the way of the trencher but find out what future plans the property may have. For example, maybe an area of your run has future excavation on it's mind. Road grading alone takes 24 inches of the top, so you should bury your cable at least 48 inches. You should also double check the requirements of your local code.

If your installing an OSP fiber optic cable, they should be buried at a minimum depth of 3.28 feet (1 Meter) but once again, think about the future!

Site conditions will also be important when selecting your bore depth. Pipelines, sidewalks and roads are just a few examples of what will influence that decision. In these cases the AHJ (Authority Having Jurisdiction) and owner set the minimum bore depth.

You also want to install an armored fiber optic cable for direct burial installations. An "Outdoor Rated Cable" is not enough to be warrantied. You must have an armor for direct burial applications.



Enclosures should provide sufficient space for splicing and proper storage. Enclosure can be in-ground or above ground type. Marker post are recommended to be placed at these locations. Don't forget, to prevent rodent and insect damage it's recommended that all in-ground enclosures with an open bottom have at least 6 inches of tamped gravel that covers the bottom of the enclosure. Pedestals should have gravel under it for at least 6 inches as well.

Oh, don't you feel better. Now install that cable!

"By Mercy Salinas"

Aerial cable installation and what you need to know

Aerial cabling has been around forever but this method does have the highest risk of taking a crap on you due to natural disasters, vehicle accidents, lightning strikes, falling tree limbs and so on. Aerial cable runs also detracts from the aesthetic appearance of the property and installation hardware will damage the exterior of your building. If an aerial cable installation is right for you some advantages will be, fast installation and easy access for maintenance. Check your local ordinance first, your aerial cable run may be restricted.

Your planned route must provide enough stabilized ground for your installation vehicle to be supported properly during the installation and later when maintenance is required. One of the most complex installations that comes to mind for us is a ski lift install requiring a PE38 cable be ran to the top of the mountain.

Here's an example of a PE38 cable from our YouTube Channel.



Pole placement should take into account your future cable capacity needs, pole type class, storm load requirement, optimum span lengths and minimum height clearance. Cable must also maintain sag clearance.

Class numbers are assigned to pole strengths with the strongest being class 1 and the weakest being class 10. Marked poles should indicated their class, species of timber, preservative treatment, and footage. If a pole is installed in a sloping ground, the depth of the pole set must be increased over the depth used for flat ground installation. An outside plant designer should know about the three definitions of pole loading: transverse storm loading, vertical loading and bending moments.

Your aerial cable suspended strand is available in two types, Class A for general use and Class C for corrosion prone areas. Proper selection should be made for pole to pole installation. The selection of span length should follow these guidelines: * Strand tension should not exceed 60% of breaking strength under storm loading conditions. * Strand tension should not exceed 70% of breaking strength with cable in place and a 300 pound load concentrated at mid span. * Sag should not exceed 10ft at a 60 degree Fahrenheit temperature, without any wind loading.

A self-supporting cable span length is limited by the simultaneous application of the two previous factors. Self-supporting cable is a special construction in which the sheath covers both the support strand and the telecom conductors. When tensioning a self-supporting cable, special clamping devices are required for the come-along to avoid cutting the polyethylene strand covering.

In almost all cases, a pole will require some type of guying hardware, which is available as side, head, anchor, pole to pole, or pole to stub guy.

You can place an aerial cable from a stationary reel or a moving reel in either of two ways. The first way, temporary pulleys or J hooks are installed at each pole, then the truck winch is fed through the pulleys, or hooks, and attached to the end of the cable.

The second way is the end point of the cable is attached to the first pole and the rest of the reel is moved to the next pole, etc. Temporary pulleys or J hooks are not needed, because the cable is attached to each pole as it is unreeled.

So maybe your thinking about direct burying your cable instead. Check out our other blog post on direct burial cable installation tips.

You might want to consider working with a outside plant designer, there is a lot of math and science involved in this type of installation. Maybe even make an investment into a OSP design reference manual to help you out.

Special thanks to Electrical Construction and Maintenance.


Any questions? Comments? Leave them below. Thanks!

"By Mercy Salinas"