A new Fire Storm!

This weekend I was climbing one Arizona AshTree in my backyard to remove a few small dead limbs. These trees need to be pruned regularly almost yearly otherwise they get full of dead limbs that eventually cause too much weight on the branches until they break down and they also reduce light intensity to the inside branches new growth killing them. This particular side of the tree has the City Electrical Primaries way above it so there is not danger of getting into those by accident and the City Electrical Co (Austin Energy) has a good clean up program to clear lines on a 2 to 5 year cycle city wide.
The lower secondary line goes into my house at a lower level an crosses a small outside portion of this Ash so I make sure to clear up any obstacles or call the city to do it if they are too risky or large for me to safely get them out of the way. This lines are insulated in strong dark plastic so I an fairly confident that there is not much danger by climbing near (10 ft or so) the lines but I am always careful never to allow any of my gear to get too close to the lines anyway. My questions is what is the opinion/experiences of other RT Climbers about climbing in this type of situation? Any stories other than the ones we have read on the Treebuzz about "professional" guys getting electrocuted? Now, let the firestorm begin!

P.S. I grew up in South America and my family owned a Hydro Electrical Power plant that served three small cities, so I have worked around electricity all my life while growing up so I know the basics of staying away from hazardous situations but I am not afraid of power lines in general. My tomb stone will probably read:
Here lays another fool, not afraid of electricity!

Might I throw a log on the fire?

Knowingly risking one’s life for adventure or profit is a daily occurrence for many of us. I have been doing high voltage work (and occasionally at great heights) for 25 years. I have seen my share of “toasted” human beings too. Still, It doesn’t bother me.

What does frighten me? . . .
Driving a motorcycle anyplace other than on dirt, like in metro or highway traffic. Now THATS risking your life.

O.K., next opinion please!

That's right on target, Electro. I long for some dirt riding like in my teen years but I know if I buy a bike I'll have it on the road. And not just any road, but a city road. My nurse friends call them organ donor machines.

Oldtimer,
Can you post a picture of how close the secondary line goes by the tree?
In general, I stay out of trees near power lines, but I have an oak in my backyard that is fairly close to power lines (about 8-10 feet). I know the tree well and I make sure I don't do anything that would cause any contact with the lines (i.e. I'm very careful where I throw the throwline). I feel comfortable climbing that particular tree.
Patrick

Originally posted by Randall R
My nurse friends call them organ donor machines.

Exactly.
The power to weight ratio on the latest crop of 21st century rice-burners can have you at 150 MPH in a flash. What a rush!

Getting back to tree climbing here. . .
Yes sir, a picture would be good. From reading Oldtimers’s post it seems as if he is well away from the high voltage stuff and only adjacent to the 220 volt feed to his residence.

Disclaimer: I’ve never been electrocuted but after observing the aftermath of those who have. . . I would heed Patrick’s words and keep clear for safety’s sake.

Which brings up a question I've been wondering about. If I put a 2.2 mm diameter throwline (assuming it's not raining, a dry day) over an insulated 220v house service line what would happen? I'm guessing nothing, the power line is insulated. If something like that happens it would not be wise to try and pull the bag back over the line.

If the throwline made contact with an uninsulated power line and a person was holding the the other end of the throwline and thereby grounding it, then what? I'm making an uneducated guess that 2.2 mm line would melt before it would carry enough juice to give a significant shock. EJ, any thoughts?

I'm making an uneducated guess that 2.2 mm line would melt before it would carry enough juice to give a significant shock.

You would die long before the line would melt--it wouldn't even get measurably warm before you were toast!

On the other hand, I have no idea what the resistivity of the various throwlines might be. If it's very high, you'd be safe; if not, . . . .

One nice thing about "SE" (do I remember correctly, EJ--"SE" for "Service Entry" cable?) is that it has the messenger (the strength member of the cable--the bare laid-wire support) for the current-carrying conductors, spiraled around said "hot" conductors. That way, if, say, a chain saw cut through the hot ones, the saw almost certainly would be in contact with the messenger, which is at ground/earth potential, effectively shorting the lines and popping a breaker, and maybe saving your life.

Another feature of SE is that it has thick, tough insulation. You are much safer treating it roughly than you are giving similar treatment to any household wiring or extension cords.

It's been way too long since I worked for a power company, so I've forgotten much of the terminology; EJ can educate us here. Be careful of the term "secondary"--it can mean different things to different people. In layman's usage, it might mean the three-wire 220V (or whatever the voltage is today) service going into one's house; to someone else, it could mean the 4.5kV neighborhood distribution lines. Again, EJ, please correct me if I'm wrong.

Personally, I would not be concerned about a small limb accidentally hitting the cable entering my house. Of course, I'd do whatever I could to prevent it--I just wouldn't be frightened of it.

On the other hand, I would not go near those 4.5kV lines.

I was reading in the Treebuzz and there is a topic about Electrical separation from power lines and a link to a table w/ the minimimum approach distances.

Table 1 - Minimum approach distances from energized conductors for qualified line-clearance arborists and qualified line-clearance arborist trainees.
Nominal Voltage to Separation
1.1 - 15.0kV 10-0ft 3.05m.

The moral of the story:
So, stay the heck away from the power lines while climbing!

My understanding from various reading (I claim no true knowledge in this matter)...and for the record I refuse to climb within 1600meters of an electrified line...
is that the "insulation" is nothing more than weatherproofing. I have read that current can pass through microscopic perforations in that weatherproofing and kill.

Climb Safe!
Icabod

Speaking of Qualified. . . Qualified is the key word here.
I (we) are only permitted to work in substations & electrified territory that we are “qualified” on.

The Load dispatcher has a list of all the high voltage locations he is responsible for, and on that list are the names of all the employees which are “qualified” at the various locations. We can only do exactly as instructed to do by the “Power Dispatcher” (i.e. load director, power supervisor, etc....) until a clearance is issued.

Every move is repeated back verbally from me to the “PD” over the radio or telephone, it’s recorded on audio tape, written down on paper, and digitally recorded in a computer log every time any high voltage switching work is done.

So, technically speaking, out of all the users on this forum, I, by law, am NOT allowed to climb any tree that is within 8 feet of a power line without the line being cleared and grounded by a H.V. Lineman which is qualified on that location.

Note: House electricians, contractors, trespassers, and other quasi-qualified personnel seem to go by a completely different set of rules. Non-qualified individuals can pretty much do as they please and if trouble should occur they then sue the living daylights out of my company. (Or so experience has shown me).

If I remember correctly, I think Climber020 is a qualified H.V. tree trimmer guy. Yes/no?

Hi, Icabod; I missed seeing you at Bob's recently.

You said:

My understanding . . . is that the "insulation" is nothing more than weatherproofing.

No that's not correct. An insulator is what it says--it's an insulator. For example, see Info about insulators . A Google search will turn up lots more--as technical or non-technical as you want.

Of course, it indeed is possible for an insulator to have small "holes" in it, but even at that, the breakdown voltage between the energized conductor and you (or whatever) would have to be exceeded. Such an "insulator" would be defective and probably would not make it off the production line.

If insulators were only weatherproofing, then you'd be at risk every time you handled an electrical appliance, extension cord, etc.

This is not an easily explained concept without getting into some relatively complex physics, but yes, insulators (proper ones) do insulate--well and safely.

There's a great thread over at Treebuzz on this topic. Check it out...

http://www.treebuzz.com/forum/showflat.php?Cat=0&Number=9703&page=3&fpart=1&vc=1

I read through the above mentioned thread on Tree Buzz.
Looked like it was all good common sense advice.

Occasionally (frequently?) a residential service drop does pass through privately owned trees. Seems like most of the crew here at the TCI forum would have the ability to tidy-up branches around such conductors without incident. If your confident that it is only a 220 volt service drop, I’m confident you can work “briefly” around the wires to do some pruning.

Also. . .
Jim W your input here has been interesting. Your utility training, no matter how long ago, still serves you well.

If I'm climbing recreationally, I don't want to have to climb WORRYING about something that I don't NEED to be worrying about. Obviously, in my work, I always don't have much of a choice...but for play, why mess with it......???....

The only time I'd do it is if the tree was THAT good and there were no other good trees anywhere close to climb.

Other than that...I like to keep fun fun and work work.

love
nick

Thanks for the nice comment, Electrojake. Like virtually everything else, once one has learned--really learned--the fundamentals, an awful lot of stuff makes sense. This is contrasted with memorizing rules without understanding the underlying reasons for them.

Randall, I read the thread on Tree Buzz. The several anecdotes told by the fellow who had fired a man for giving dangerous advice were excellent. Most point out how easy it can be to "do something dumb." I've done my share; very scary. A few of them make me realize how very fortunate I am.

BTW, a few of the ideas in that thread are just plain wrong. I continue to be amazed when someone says, "I don't know anything about this subject, but here's what you have to do . . . ."

Nick makes a good point. There is one tree on my property with power lines passiing through it. This could be a fairly good climb except for the lines . . . interesting that I have not even considered going into it.