When folks ask me for an estimate of the cost of building aerial fiber, I always say that the cost is dependent upon the amount of required make-ready needed. Make-ready is well-named – it’s any work that must be done on poles to be ready to string the new fiber.
One of the most expensive aspects of make-ready comes from having to replace existing poles. Poles need to be replaced before adding a new fiber line for several reasons:
- The original pole is too short, and there is not space to add another wire without upgrading to a taller pole. National electric standards require specific distances between different wires for technician safety when working on a pole.
- It’s possible that the new wire will add enough expected wind resistance during storms that the existing pole is not strong enough to take on an additional wire.
- One of the most common reasons for replacing poles is that the poles are worn out and won’t last much longer. That’s what the rest of the blog discusses.
Poles don’t last forever. The average wooden utility pole has an expected life of 45 to 50 years. This can differ by the locality, with poles lasting longer in the desert where there are no storms and having a shorter life in more challenging environments. It’s easy to think of poles as being strong and hard to damage, but the forces of nature can create a lot of stress on a pole. The biggest stress on most poles comes from the cumulative effect of heavy winds or ice pulling on the wires and attachments.
There are a lot of reasons why poles fails:
- Although most poles are usually made of rot-resistant wood, the protection eventually wears off, and poles can decay. This can be made worse if vegetation has been allowed to grow onto a pole.
- Using a pole differently than the way it was designed is common. A pole might have been rated to carry utility wires but over time got loaded with extra attachments like electric transformers, streetlights, or cellular electronics.
- The soil around the base of a pole can change over the decades. The area may now be subject to flooding and erosion that wasn’t anticipated when the pole was built.
- Somebody might have removed a guide wire that was supporting the pole and not replaced it.
- A pole may have been hit by a car, but not badly enough to be replaced.
ISPs complain when saddled with the full cost of pole replacement. Many of the issues described above should more rightfully be borne by the pole owner. But the federal and most state make-ready rules put the entire cost burden of a pole replacement on the new attacher. It is clearly not fair to make a new attacher pay the full cost to replace a pole that was already in less than ideal condition.
It may seem to the general public that poles are just stuck into the ground. But if you’ve ever watched a new pole being placed, you’ll know that the process can be complex. The design of any new pole must account for all of the anticipated stresses the pole will have to endure. This includes the weight of the wires in a windstorm, ice accumulation, soil composition, the quality of neighboring poles, the spacing between poles (the greater the spacing, the more weight and wind resistance), and if the pole is standalone or to be guyed (anchored to the ground with several strong supporting cables).
Most engineers estimate that a generic aerial construction project will require replacing around 10% of the poles. It’s a pleasant surprise when the percentage is smaller but it can be a real sticker shock if a lot of poles must be replaced. I’ve seen projects where an electric company has neglected maintenance and most of the poles were inadequate.
The right question to ask is not how much it costs to build a mile of fiber. The better question to ask is how good are the poles?
Great posting Doug. Jane Smith Patterson