By Michael “House” Tain
Regardless of where a tree crew is working, electricity is probably part of their work environment, either aloft or underground. Sadly, sometimes tragically, tree workers who don’t specialize in line clearance often don’t even recognize that this danger is lurking. Whether it’s willfully, meaning Johnny knew the line was there and got too close anyway, or ignorantly, meaning Johnny fell into the trap of misinformation and lack of knowledge about the insulation of utility lines or how close one can get, the end result is the same — a spot in Dr. John Ball’s regularly updated statistics on tree work accidents and fatalities. Electricity is a fickle beast, and, in a sense, a force of nature, it really does not care whether a crew member knows it’s there or not, or if the person knows safe working practices around it. All electricity cares about is getting back to the ground as fast as it can; and a climbing arborist or ground person with a polesaw will work just as well for that purpose as a copper line.
Safe working practices around electricity are fairly straightforward, and don’t require a great deal of effort to comply. But as every industry member knows, there are a lot of safe practices, regarding almost every facet of the industry that get ignored or skipped “just this one time” every day. All safe practices have value and are important, but when one talks of electricity one is discussing a force that will stop a heart or send it into a fatal rhythm, blow holes through flesh, and heat skin to the point body fluids boil and smoke. As is said in my neck of the woods, “The electric ain’t something to mess around with.”
Arborist versus Line Clearance Arborist
This is a pretty simple principle and standard, yet one that a lot of members of the industry see violated, or even perhaps violate knowingly, everyday. It’s simple, personnel that have not received the required training, education, and evaluation that comprises a Line Clearance Arborist or a Line Clearance Arborist Trainee do not get closer to energized conductors than the minimum approach distance. This is not intended to make tree crew member’s lives more difficult, nor is it intended to prevent companies from bidding on jobs, it is meant to prevent the horrific wounds, burns and deaths that can occur from contact with electricity.
Not how close, but how far
The table below shows the previously mentioned minimum approach distance for arborists who are [ital>not<ITAL] any line (as can be seen from the table); second, more insulators in general means more “juice,” thus stay further away from the line. Many utility and power companies are happy to give a quick class to tree crews on how to identify the rough voltage that a given line is carrying; and there are any number of tree industry seminars and classes that also address this knowledge. Electricity, given the right atmospheric conditions and voltage levels can easily arc through the air to a crew member who just wanted to get “a little bit closer.” Stay the proper distance away, or, if unsure, very far away; and the voltage will not have this opportunity to radically alter body chemistry and function.
Kilovolts phase to phase
0.0 to 50.0
50.1 to 72.5
72.6 to 121.0
138.0 to 145.0
161.0 to 169.0
230.0 to 242.0
345.0 to 362.0
500.0 to 550.0
785.0 to 800.0
Where’d that come from
This means the tree worker’s body has come in direct contact with the electrical conductor; and it usually happens when a crew, climber, or lift operator hasn’t evaluated the tree and site for hazards. In short, the line is never seen on the back side of the tree or disappearing into the canopy and somebody moves or swings right into it. Direct contact can also happen when the worker knows the line is there, but has gotten busy and has a moment of inattention, ending with fairly dramatic or tragic effects. Storm clean-up or work situations can also be ripe with direct contact possibilities. There may be any number of lines down, tangled in brush, or settled down on top of trees, all of them “live” and looking for a quick and easy path to the ground through a tree worker’s body. A knowledge of the minimum approach distances, with a good pre-work hazard inspection, will go a long way toward preventing the possibility of direct contact.
The path of least resistance
Line clearance may often take place in fairly isolated rural settings.
Photo by Mike Schronk, Carolina Tree
The head does more than hold the helmet
As stated, folks that aren’t line clearance certified should [ital>nevernot<ITAL] of be should crew tree is how the in much which that and line to on material an it around some a P line.
It’s not really the ground’s fault
Ground fault is when the ground itself becomes energized. This may occur from a downed line, or even when electricity travels through a non-insulated lift and goes through the outriggers. Whatever caused the ground fault, it is not a good situation. The crew member that was leaning against the truck will not even realize that a ground fault has occurred as they will already be trying to figure out what hit them. The area of soil with electricity will vary with moisture, voltage, and soil structure, but it will certainly be energized; and a crew member stepping from an area of low voltage to one of high has presented an excellent pathway for the “juice.” Often called step potential, this occurrence can be minimized by taking very small steps — almost shuffling or hopping with both feet together — away from the source. This will decrease the likelihood of being in areas of widely different voltages at the same time.
“The electric” is almost always there; and this article didn’t even address the dangers of stump grinders, tree planting, etc. and underground lines. The nature of electricity cannot be changed, nor can the conductivity of the human body; and mixing both together is a recipe for tragedy. Being able to identify the presence of electrical hazards, and knowing the safe work practices and distances in its vicinity will go a long way toward making tree crews safer.
Michael “House” Tain is a contract climber, splicer, educator and writer associated with North American Training Solutions www.northamericantrainingsolutions.com and Arbor Canada Training and Education www.arborcanada.com. He is currently located in Lancaster, Ky., and can be reached via e-mail at email@example.com.