Hi! I'm new here although I've been lurking around.

My question is how should one think about power lines? I like to climb in the patch of woods that runs behind my house, but there are a number of powerlines and phone lines that run through the area. I know better than to climb next to them, but how far away is safe?

I had not really paid much attention to them until the other day after I realized that my throwline was hanging over one. Now I'm starting to wonder about it.

That is the answer to your question!
You never know when your throw line or climbing line will go over and fully energized line and in a few nanoseconds you could be a casualty.

Stay the heck away from power lines of any kind and look before you throw your throwline up and see where it will land.

The number one killer of tree workers is electrocution.

Stay well away from any lines. Even phone/cable lines can have 100 +/- volts in them. That'll get your attention!

The higher the voltage in the lines the further the voltage can leap to YOU!

I would argue that if you're climbing so close to power lines that you can accidentally get a throwline over one, you're climbing far, far too close to them!

In the U.S., primary line distribution is 13.2KV. Get across that, or between one side and ground, or even close enough--under the right conditions, and you're toast.

Jim

A generally accepted rule for rec tree climbing is don't climb a tree that has an energized line within the dripline of the tree or within close proximity to the outer edge of the dripline of the tree. Dripline being the horizontal perimeter of a tree's crown. Some climber's use a 20 ft. rule others use a 50 ft. rule as the minimum distance from the line to the dripline.
-Andrew

Think tubes.

The tree's dripline is the outer perimeter of the vertical tube.

The power line is the center of the horizontal tube.

Depending on a climbers training, I'm speaking of pro-climber and OSHA regs, the closest those two tubes can be is ten feet.

There are two laws that can't be negotiated. One, gravity sucks. The other, electricity always goes to ground...through air, tree or flesh...it doesn't care.

If an overthrown throwline is over a line, you're likely way too close to climb that tree. And, work on controlling your overthrows. There are trees on the edge of the Minimum Approach Distance that might be chosen to climb. It's easy to overthrow...be careful!

Somedays my throwing is so bad, the throwline ends up far away from the tree I'm trying to get into.

Sometimes while using the Big Shot the throw weight bounces in a direction completely different from where you intended and your throwline ends up crossing right over or resting on a high voltage power line (speaking from experience) luckily the line was dry and clean enough that not electrical charge arched over but for a while I was not sure how to retrieve the line and remove the throw weight. It took me a while to figure out if it was safe to approach the line while holding a non conductive pole and heavy welding gloves. Not recommended technique!

Seems like one rule of thumb would be to have at least one full-sized tree canopy between the power line and the tree you are trying to get into, that way if you get a ricochet (and you will) at worst it'll get caught in the next tree over. I've always admired many of the trees along the sides of the powerline behind our cabin, but I've never climbed any of them.

My rule of thumb is to consider the height of the tree and then climb only if that same number represents less than the distance between the tree and the power lines. I can understand why tree workers need to sometimes climb closer than that, but for a recreational climber, I think that's a pretty good rule of thumb. It's what I teach students anyway.

By the way...has anyone ever really taken a close look at the electrical conductivity of a dry rope? Or a wet rope? or even a wet or dry throwline?

It is my belief that dry rope would make a good insulator. Throwline, to me, appears to be nothing more than thin, light, slippery rope.

Wet rope is not something I'd want to be hanging on to if it got across a sufficiently highly-energized conductor. (E.g.: One of the aforementioned 13.2KV primary distribution lines.) How "good" a conductor it would make would be dependent upon a variety of factors. If it was uncontaminated and the wet was from purely distilled water: No different from dry rope. (My head knows this. My heart says "No way in hell would I touch it, anyway!" ) High degree of (conductive) contamination: Probably a "relatively" good conductor.

Jim

I have a wonderful pine tree next to some distribution lines. Distribution voltages in residential areas is probably under 50,000 volts. The line maintenance crews cut back some of the limbs in their sweep through the area. Here's the thing: If that tree is too dangerous to climb, is it too dangerous to touch as well?

In the touch scenario, the person is in firm contact with the ground via his feet, let's say he's barefoot for sake of discussion. If he touches the tree, is he in danger? If he is, the power company has exposed itself to big time liability risks for making a tree in someone's yard dangerous, if not lethal. Can you imagine the ramifications of a child playing in his yard and coming in contact with a tree that had limbs too close to a distribution line!

The trimming the contractors did in no way meets the dual 10 foot cylinder guideline. So if it doesn't meet that, and the tree is dangerous, is it not even more dangerous to someone on the ground?

When you are in the tree, you have lost contact with earth ground which is where the current will try to flow to, and all you'd have to worry about is voltage gradient over the length of the tree, after all, you aren't grounded.

Ropes and throwlines are another issue. Polyester and nylon are great insulators. The problem is they get contaminated and we have no idea what the conduction of the rope might be. Even then though, if you are cleanly suspended by a rope, i.e. not in contact with the tree or ground, there is no path for current to flow. Theoretically you could be suspended on a copper rope and not be in danger of getting shocked or worse. It's if/when you touch the ground that the danger occurs. When you touch the ground the current has a path - through the rope and you to ground.

I've had my ZingIt across two distribution lines at the same time and nothing happened. Again, the throwline is an excellent insulator. I felt nothing and the line wasn't burned or damaged in any way by being across two phases. I just pulled it down and waited for my heart to restart.

I'm not saying climbing in a tree near a power line is safe, but rather if it is unsafe for climbing due to it's proximity to a power line, it is equally dangerous or perhaps moreso, to touch.

Practically speaking from a rec climbing point of view, there's no reason to climb trees with powerlines through the crown or close to the crown. This does not in any way imply that such a tree is therefore dangerous to touch while standing on the ground. When considering best practices for rec climber safety around wires it's a good idea to first lower overall probabilities of accidentally coming into contact with live wires, ie: don't climb the tree. Nobody contacts live wires intentionally, if you're not in the tree you have no chance to make the mistake that causes you to get in between the path to ground.

From the point of view of a work climber who's job it is to do line clearance there are very specific best practices, rules and regs, ratings, certs etc.

If you are in a wet tree and accidentally contact a live wire wire with your hand, saw or your wet climbing rope there is an opportunity for the current to pass through all or part of you on the way to ground though the tree you're in. In a dry tree it seems the danger is less but I can imagine some scenarios where a climb can still get into trouble, especially with the high voltage lines often found in the highest position on the pole, that kind of potential doesn't need wet to move to ground.

As I recall from reading over accident reports a classic scenario is a climber makes a pruning cut, the limb goes the wrong way and lands on a live wire but does not completely separate from the tree, or the butt end contacts the climber, either way the juice finds ground through the climber (depending on their position in the tree, position of hands feet etc.) and death may be the result.
-Andrew

I didn't get the impression from the comments that anyone was talking about a wet tree, or power lines running through the crown of a tree, or a person being in a tree close enough to power lines to touch them, or being in a tree that has limbs that contact power lines. Those seem rather obvious. The issue as I understand it is how much distance one needs to between the nearest point(s) on the tree to the power line.

Hunabku and I have both climbed the tree I referenced in my post. I don't climb it often, because it's just out of my comfort zone, more than a real danger. The tree is beside the power lines; they don't run through it.

The point remains and is accurate, if a tree is too close to a power line, it is as dangerous to touch as it is to climb it, perhaps even moreso because you're in contact with the ground and that's where the current will flow to. Line maintenance crews can actually touch 161kv lines safely from a helicopter because there's no ground path.

So if a tree is beside a distribution line and too close to climb, it's probably more dangerous to touch. But, if one is talking about climbing a tree and the climbing process puts you ever closer to power lines, yes then that would be extremely dangerous.

I've done the same over a single line on a dry day with no problem, throw went too far horizontally. Just untied the bag and pulled the throwline back over the wire. I've wondered if the part of a wet thowline contacting bare (or thinly insulated live wire) would blowout (melt) before delivering enough juice to injure you.

I've watched a downed tree hanging across two high voltage lines and it just sat there and cooked on the lines, I can't imagine throwline last more than a split second.
-Andrew