The power company would have to give permission or rent the use of the poles to the internet companies to run fibre on.

It's pretty cheap. Electric company for shure have calculations for poles ownership and maintenance. It is fully covered by tiny part of your electricity price. The only additional expense is to take some care of fiber when doing some repair work on poles. Usually it is purely symbolic price. Often electric company do that just in exchange to internet connection for their powerline monitoring devices.

Also, if you are in small settlement or have dedicated power line, and want to throw fiber by yourself, try to talk with powerline maintenance guys. Nobody except them know what is on the poles in their zone of responsibility, so they often agree to care about fiber during repair for symbolic price. If they live in your settlement it is even easier - jusr share some internet with them or make a discount.

What do you guys do with the fibre lines to make them not snap in winter if they’re on the power lines? With ice building up even the steel power lines they’ll snap and need to be repaired in the winter. Is there a steel sheath over your fibre line to keep the ice from breaking it during the winter?

You need self-supporting fiber. It made differently from inhouse and underground ones and is pretty good at withstanding all loads cable could expirience when run on poles.

First, such fiber is thin and its outer insulation usually made from polyethilene, so ice can't build up on them in any significant amount, it just does not stick, and easily fall off.

Second, fiber is reinforced with steel or fiberglass rope, so it is very strong, even thin 4-8 fiber ones with diameter of 5-6mm are usually as strong as power wires. Sometimes it even could hold a small fallen tree without problems for connectivity. Fiberglass reinforced is noticeably cheaper and often better than steel reinforced one. Even if moisture somehow sneak unde the outer shell, it will not rust. It is lighter with same strength so it could withstand larger load. Also it does not stretch with the time under own weigth.

Third - optical fibers run loose inside small central tube filled with half-liquid gel, so it have a huge reserve for elongation and/or bending

And last one - unlike power lines fiber does not heat up, it have ambient temperature, so there is much lower probability of ice buildup on them.

The only thing that is not recommended to do at low temperatures is fiber welding. If fiber is torn in winter, guys weld it back inside a warm van/truck cab, adding a long enough piece to make it possible, and then reel excess into a loop on a closest pole.

All in all winter, even severe one is not a problem for a fiber. Most often fiber is damaged by fallen trees, along with power lines, and it usually happen during summer thunderstorms and/or hurricanes.

Only specific thing with fiber is that you need an relatively expensive device to weld it together or add an endings with connector to it. Usually it is not a problem because any provider have such device and will not hesitate to repair fiber that bring them money. You could also buy a used one for cheap. For personal use, if you don't need to weld fiber daily, it will be more than enough.

The power company would have to give permission or rent the use of the poles to the internet companies to run fibre on.

It's pretty cheap. Electric company for shure have calculations for poles ownership and maintenance. It is fully covered by tiny part of your electricity price. The only additional expense is to take some care of fiber when doing some repair work on poles. Usually it is purely symbolic price. Often electric company do that just in exchange to internet connection for their powerline monitoring devices.

Also, if you are in small settlement or have dedicated power line, and want to throw fiber by yourself, try to talk with powerline maintenance guys. Nobody except them know what is on the poles in their zone of responsibility, so they often agree to care about fiber during repair for symbolic price. If they live in your settlement it is even easier - jusr share some internet with them or make a discount.

What do you guys do with the fibre lines to make them not snap in winter if they’re on the power lines? With ice building up even the steel power lines they’ll snap and need to be repaired in the winter. Is there a steel sheath over your fibre line to keep the ice from breaking it during the winter?

First, fiber is thin and its outer insulation usually made from polyethilene, so ice can't build up on them in any significant amount, it just does not stick, and easily fall off.

Second, fiber is reinforced with steel or fiberglass rope, so it is very strong, even thin 4-8 fiber ones are usually as strong as power wires. Sometimes it even could hold a small fallen tree without problems for connectivity.

Third - optical fibers run loose inside small central tube filled with half-liquid gel, so it have a huge reserve for elongation and/or bending

And last one - unlike power lines fiber does not heat up, it have ambient temperature, so there is much lower probability of ice buildup on them.

The only thing that is not recommended to do at low temperatures is fiber welding. If fiber is torn in winter, guys weld it back inside a warm van/truck cab, adding a long enough piece to make it possible, and then reel excess into a loop on a closest pole.

All in all winter, even severe one is not a problem for a fiber. Most often fiber is damaged by fallen trees, along with power lines, and it usually happen during summer thunderstorms and/or hurricanes.

Only specific thing with fiber is that you need an relatively expensive device to weld it together or add an endings with connector to it. Usually it is not a problem because any provider have such device and will not hesitate to repair fiber that bring them money. You could also buy a used one for cheap. For personal use, if you don't need to weld fiber daily, it will be more than enough.