BlueRidgeMark
Addicted to ArboristSite
not trying too step on any body's toes here, but who do you work for because if they have told you that the "insulation" will keep you safe from being killed and that because the wire is "insulated" means you can touch it then they are wrong, keep thinking that you can't get hurt by a line that is "insulated" and you might just get bit pretty dang bad or killed, the power company's also have coated primary wires, would you grab one of those? I have seen 24,000 volt lines "insulated" lay on the ground burn and blows chunks of asphalt and concrete up as bigs as 20 inches in diameter and 2 to 3 feet deep so if that was "insulated" then why did it do that? also, when I was in Louisiana after Katrina there was a guy killed by a so called "insulate" wire.
Your post is a good illustration of what I was trying to tell Dil. A wrong understanding of what the word means can be dangerous.
Insulation does NOT mean that it will stop any and all current from flowing. It's not a black and white, on or off thing. It's not, either INSULATED, and no current can flow, or it's UNINSULATED, and current will flow. It's a continuum, a sliding scale.
It depends on the insulation and the voltages involved. And when I say the insulation, I mean the AIR insulation (that is, the space between you and the line) as well as the plastic or rubber or whatever material is being used for insulation. It depends on the THICKNESS of the insulation and the type of material (whether plastic or air or whatever). And not that it matters to this discussion, but whether it's DC or AC, and what frequency, also makes a difference.
It takes a lot more insulation to stop 24,000 volts from going where it wants to than it takes to stop 120 volts. What may be adequate insulation in one situation (up on a tower) may NOT be adequate insulation in another (laying on the ground).
Insulation is a lot LESS than you folks seem to think. It's just something that is intended to prevent electric current from going where it's not wanted. That's all. It's NOT a guarantee of safety.
If you have ENOUGH insulation, you can work around wires. That's what you do when you keep XX feet away from a wire with YYY voltage. That DISTANCE is insulation. Air insulation. The insulation on a service drop (usually polyethylene) is a much more effective dialectric than air , so you don't need as much to control the flow of current. This means you need LESS distance. Now you need mils instead of feet.
That's why Sally's local utility doesn't mind them trimming from the ground. They have proper training, and they are using proper tools for THAT job.
Have you ever seen a tree branch rubbing a service drop? Of course, you see it all the time. No big deal. Trim it back before it rubs through... What? The insulation. The stuff that keeps the two phases from shorting out.
And I keep asking this question, and nobody is even trying to answer me:
Where did I say that service drops are "safe"?