powerlines

[Powerlineman]

Powerlineman...what are the safe cutting distances (based on line voltage), assuming nothing is touching or is going to touch any part of the line, even when it falls? In other words when you suggest "not trimming any tree near lines", what distance is near?

I dont want to give exact numbers because when it comes to trees and powerlines every situation is a little different. If I tell you 8, 10, 12 feet etc. that number wouldnt work for every situation b/c as you know each tree job is different. I dont know of any power companies that wont come out and drop the line or the tree for free, so why not take advantage of it. I would rather drop a line or trim a tree for someone than have them drop the tree on our wires or worse get killed.

So to sum it up I dont want give any solid numbers and see you or someone else get hurt, use comon sense, if you have to stop and look at the project to long give the power company a call. Look at it this way half the work will be done for you for free.

 

[BlackenedTimber]

As some of you may know, I work in the power transmission and renewable energies industries as a project manager, and owned a tree service before I got involved in power. I have daily worked around live power, up to 600kVa (600,000 volts/amps) Three-phase AC. With stuff that hot you have to rotate in and out or the extended exposure can kill you over the long-term from secondary diseases.

I generally use 15 ft of clearance on any line as a rule of thumb, but as others have suggested, depending on the voltage and ampacity, this can vary considerably. Think about this: If you were able to touch a 9V battery (the weird looking rectangular ones...) to your heart, the 4.5 amps that the little battery puts out would be enough to kill you. It's not just volts, but amps as well. I think its 6 or 7 MILLIAMPS across your heart can kill you.

If the line is a service (drop) line or local distribution, you may be able to get it dropped for the day to complete the work. If the line is a transmission line you will not be able to get it dropped.

As others have suggested, contact the power company in your area. They would rather send out a truck and remove some/all of the tree, drop the line, or insulate the line, rather than have a casualty and loss of service on their hands.

Good luck and stay safe.

T

 

[ropensaddle]

Being I am a lineman by trade I figured I should chime in here. Insulated or not I would strongly suggest not triming any tree near lines, insulated or not. You dont know if the insulation is worn through or cracked. I have seen many limbs that have rubbed right through the insulation and you didnt even know it.

My suggestion is have the Electric company come out and top the tree under the line and then do the clean up. I do this all the time the tree contractor gets paid and goes home alive. Win - Win for everyone.

More people are killed by secondaries than primaries I have cleared 500 kv down to 240 service drops are the least feared but most dangerous. They are frequently inside the tree with a climber and many times rubbed raw as you said. I have pulled overhang over 3phaze and primaries burning it is dangerous work better left to those that know not to complete the circuit and how to avoid it.

 

[ropensaddle]

As some of you may know, I work in the power transmission and renewable energies industries as a project manager, and owned a tree service before I got involved in power. I have daily worked around live power, up to 600kVa (600,000 volts/amps) Three-phase AC. With stuff that hot you have to rotate in and out or the extended exposure can kill you over the long-term from secondary diseases.

I generally use 15 ft of clearance on any line as a rule of thumb, but as others have suggested, depending on the voltage and ampacity, this can vary considerably. Think about this: If you were able to touch a 9V battery (the weird looking rectangular ones...) to your heart, the 4.5 amps that the little battery puts out would be enough to kill you. It's not just volts, but amps as well. I think its 6 or 7 MILLIAMPS across your heart can kill you.

If the line is a service (drop) line or local distribution, you may be able to get it dropped for the day to complete the work. If the line is a transmission line you will not be able to get it dropped.

As others have suggested, contact the power company in your area. They would rather send out a truck and remove some/all of the tree, drop the line, or insulate the line, rather than have a casualty and loss of service on their hands.

Good luck and stay safe.

T

1 tenth of one amp in 12 vdc can kill you.
What in line clearance actually kills is resistance or really lack of. Ie direct or indirect contact. Humidity and a whole other host of variables. We had a guy that was hit by 69kv direct and lived but had permanent damage and holes in his feet. It is definitely what you don't know that will kill you. Especially clearing burning trees manually.

 

[Rftreeman]

1 tenth of one amp in 12 vdc can kill you.

that's probably the first thing I was told the first day I started line clearance and they gave me that little flier thingy with all the safety stuff in it (from asplundh) and I was quizzed on it.....also got my length of rope to learn my knots...


oh yeah, I got the dreaded bush axe and handsaw that week to....

this was the fall of 1988..

 

[fsfcks]

Thanks guys. As I've already posted above I had already contacted my local utility company. What I thought was a transmission line is "only" a distribution line at 34kV. I am waiting for the distribution line maintenance department to call me back and we can take it from there. Thanks for all the comments.

 

[BlackenedTimber]

1 tenth of one amp in 12 vdc can kill you.
What in line clearance actually kills is resistance or really lack of. Ie direct or indirect contact. Humidity and a whole other host of variables. We had a guy that was hit by 69kv direct and lived but had permanent damage and holes in his feet. It is definitely what you don't know that will kill you. Especially clearing burning trees manually.

good post Rope.

 

[ropensaddle]

that's probably the first thing I was told the first day I started line clearance and they gave me that little flier thingy with all the safety stuff in it (from asplundh) and I was quizzed on it.....also got my length of rope to learn my knots...


oh yeah, I got the dreaded bush axe and handsaw that week to....

this was the fall of 1988..

I was a bit before that ohhhhhhhhhhh the orange wennie days lol gotta love em:hmm3grin2orange:

 

[utilityman]

34 kv is nothing to mess with!

Just to let you know fsfcks 34 kv is nothing to mess with! It is classified as sub transmission voltage where I come from. The voltage on 34.5 kv is 19200 volts to ground. We do not glove anything over 15 kv from our bucket trucks and do not work anything higher than 4800 volts off the pole. 35 kv has to be hot sticked in our state.

Please wait for the electric company to help you.

 

[fsfcks]

utilityman...I completely agree and understand. Sorry if the "only" was mis-understood. I am waiting for the utility company to call me back.

 

[ropensaddle]

utilityman...I completely agree and understand. Sorry if the "only" was mis-understood. I am waiting for the utility company to call me back.

Shoot it's only 500 kv just enough to push 20 trains :hmm3grin2orange:

 

[fsfcks]

Just heard back, and it is pretty easy process. The utility company will inspect the line and for no charge provide 10 feet of clearance straight up on either side of the power lines. They will leave any debris for me to clear up, which is fine since my contractor can handle that at the same time as he clears everything else. That will make the remaining clearance much safer.

 

[ropensaddle]

Just heard back, and it is pretty easy process. The utility company will inspect the line and for no charge provide 10 feet of clearance straight up on either side of the power lines. They will leave any debris for me to clear up, which is fine since my contractor can handle that at the same time as he clears everything else. That will make the remaining clearance much safer.

Yup well done just be safe with the rest should not be too bad.

 

[lawrencetreeman]

fsfcks, Where abouts in Kansas are you located?

 

[StewartTreeCare]

river birch growing into the powerlines. could this shock a guy by the limb touching the lines? I dont usually mess with these jobs but i was thinking about this one.

ABSOLUTELY!!!! I used to do this when I worked for asplundh. Safe cutting distance AT A MINIMUM is 2'6". I advise you to leave it to someone with more experience, however if you feeled compelled to do this wear natural fiber clothes not synthetic because that will melt and severely burn you.. Use all insulated tools such as fiberglass because electricity can travel through wooden pole saws. If a branch is touching try to cut it from the ground with a pole saw or pole clip. Stay as far away from the lines as possible when climbing because electricity can and will arc, more on humid days. If your line is wet make sure it does not contact the line. If at all possible ask the utility company to schedule a power outage for you because this is a very dangerous task you are facing!

 

[ropensaddle]

ABSOLUTELY!!!! I used to do this when I worked for asplundh. Safe cutting distance AT A MINIMUM is 2'6". I advise you to leave it to someone with more experience, however if you feeled compelled to do this wear natural fiber clothes not synthetic because that will melt and severely burn you.. Use all insulated tools such as fiberglass because electricity can travel through wooden pole saws. If a branch is touching try to cut it from the ground with a pole saw or pole clip. Stay as far away from the lines as possible when climbing because electricity can and will arc, more on humid days. If your line is wet make sure it does not contact the line. If at all possible ask the utility company to schedule a power outage for you because this is a very dangerous task you are facing!

False on the wooden pole pruner if it is like the ones we used before you ever saw a power line. They would not conduct as they were kiln dried and sealed they would however give you a nasty splinter on occasion lol. The only advice that makes sense here is; if you are not qualified in line clearance you would be breaking law by attempting to trim or cut anything closer than 10 foot to a energized conductor. Asplundh minimum separation does not pertain to unqualified tree trimmers. Also 2'6" will change as voltage increases and is the minimum distance your body can be to an energized conductor not a branch. I have been doing and supervising line clearance for over two decades and removed burning overhang daily for many years. I am qualified but will not do their clearance for them. I will let them trim it if there is any chance of outage because; I do not wish to pay them for time and material. In summary; if you have not worked around lines long enough to become proficient with the tools and skill required to safely perform these operations, usually five years, then your illegal to be within 10 foot of any energized conductor including house drops. The good thing is; by having that law, if you are a untrained tree service and you call them and tell them your doing a job that has a conductor closer than ten foot, many times you can watch them do your work partially lol.

 

[gwiley]

i cut a power line once

We live on a few miles of private road and are a few houses short of the end of a power line. After hurricane Isabel came through we had to remove a ton of trees down on our road, power was out and the power company was still a few weeks from our area so....my Dad, brother and a friend jumped on our 4-wheelers with our chainsaws and starting working our way up the road clearing it.

One pine with a bushy top had fallen directly on the uninsulated power lines - they were hidden in the bush. I bravely went to work clearing the crap so that we could get to the trunk and find a way to get this thing off the lines when suddenly everyone stops their saws and starts yelling at me. I came up under a branch and actually cut right through the power line severing it neatly. I think that I was personally responsible for adding a few more days to the power outage at our houses.

And yes, I know now how incredibly stupid that was - but feel free to pile on.

 

[ropensaddle]

We live on a few miles of private road and are a few houses short of the end of a power line. After hurricane Isabel came through we had to remove a ton of trees down on our road, power was out and the power company was still a few weeks from our area so....my Dad, brother and a friend jumped on our 4-wheelers with our chainsaws and starting working our way up the road clearing it.

One pine with a bushy top had fallen directly on the uninsulated power lines - they were hidden in the bush. I bravely went to work clearing the crap so that we could get to the trunk and find a way to get this thing off the lines when suddenly everyone stops their saws and starts yelling at me. I came up under a branch and actually cut right through the power line severing it neatly. I think that I was personally responsible for adding a few more days to the power outage at our houses.

And yes, I know now how incredibly stupid that was - but feel free to pile on.

Ok first, if cutting one line made it take a few more days, then those linemen are lazy as; it only takes a few minutes to put a splice in. Now the stupid part is, working on downed lines that have not been properly isolated and tagged. Many a good lineman and tree cutter has been killed by dead lines. The reason is usually linked to improperly outfitted generator's back feeding and the terrible thing is, the transformer works both ways and steps up the voltage back feeding. So yeah, it was stupid, not because you cut a line but merely because proper grounding chains on both sides of the work area is a requirement in safe emergency storm operations. That little 3500 watt generator can produce 7200 volts going through the transformer in reverse.

 

[gwiley]

Ok, that is even worse than I realized. I forgot about the potential for backfeeding! Thanks for the reminder. (slaps self, writes on wall 100 times "I will not cut things touching powerlines")

 

[ropensaddle]

Ok, that is even worse than I realized. I forgot about the potential for backfeeding! Thanks for the reminder. (slaps self, writes on wall 100 times "I will not cut things touching powerlines")

Don't let the line slap you buddy lol it won't be as gentile as your hand.