Most ISPs that build much aerial fiber run into situations where a lot of poles are in bad shape that must be replaced. This adds both cost and time to a fiber construction project since the pole replacement process can be expensive and slow.

There are a lot of reasons why wooden poles go bad over time:

• Rain, snow, and humidity can cause poles to rot and decay, particular at the ground line where soil touches the pole. Moisture often brings fungal decay.
• Seasonal changes in weather can cause poles to expand and contract and cause cracking that allows in moisture.
• High wind can cause cracks in poles that can get worse over time. Overloading poles with too many wires can speed up deterioration.
• Termites and wood-eating insects can erode a pole’s strength. Woodpeckers damage poles by drilling small holes that expand over time.

All wooden poles naturally rot and decay over time and eventually go bad. Industry literature abounds with estimates that wood poles should last between thirty and fifty years. Those lives would suggest that perhaps 2.5% of deteriorated poles should be replaced with new ones every year.

Many poles get replaced before the end of economic life.

• The biggest cause of early pole replacement comes from road widening. Utilities can sometimes reuse some poles during this process.
• The next biggest category of early pole replacement come from line upgrades. This mostly comes from electric utilities wanting to add heavy wires to existing poles. But sometimes adding other wires like coaxial cable or fiber requires a new pole to handle the wind load.
• The other big cause of pole replacement is traffic accidents, which is unfortunately common since most poles are placed immediately adjacent to roads.
• There can be a lot of localized pole replacements caused by tornadoes, hurricanes, and ice storms.

But even with the early replacement, a utility should expect to replace more than 2% of poles every year. We have a huge national inventory of bad poles because most utilities are replacing poles at half that rate. Utility practices differ, and there are some utilities where poles are mostly in good shape. There are also utilities at the other end of the scale, and I know of a few small rural utilities where the vast majority of poles need to be replaced.

Unfortunately, there are no national laws that require utilities to keep up with pole replacement. Many utilities only replace those poles each year that are in danger of collapse, meaning the average age of their pole inventory keeps climbing.

Utilities are loathe to replace too many poles since it leads to higher electric rates. I have talked to small electric companies that are hoping that fiber construction will bail them out of their aging pole problem by having a fiber builder paying to replace a lot of poles.

I know pole replacements aren’t at the top of anybody’s list. Unfortunately, poor utility pole replacement practices continue to add a lot of cost to fiber projects. If nothing is done, sometime over the next 20-30 years we’ll see some utilities have catastrophic numbers of pole failures. Maybe these utilities are waiting for mother nature to somehow fix the problem for them.