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[Motorman]

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[Gerald Arana]

If there was no chance of making contact, how close could you fly to power lines? In other words is there some reason not to fly close to power lines other than contact?

MM

Yes! Fly away as far as possible! Back in the late 40's, Jim Norvel thought he could fly close to power lines and guess what..................ZAP! He's no longer with us.

The warning is there for a reason.

Jerry

[Peter Nevai]

You really do not want to find out how close you can fly to power lines. The High Tension power distribution power lines on those towers carry up around 25K volts, Your flying lines (Unless Dacron 1/2 stuff) act as nice long electrical inductors. Being any closer than a foot ball field length and you are taking chances. Also if you start hearing thunder even if you cannot see the storm, time to wrap up flying as the lines will induce the static electricity in the air right into you. No fun at all getting zapped multiple tiimes before you can land the plane.

[Brett Buck]

Did the plane hit the power lines or did a spark jump over the gap? Not talking about high towers just domestic poles. Plane will fly @ 15' only.

   A fair number of people have used the reasoning you are using, and got electrocuted. Last one I know of was a local flier about 15-20 years ago.

   There's no real rule of thumb or solid guidelines, but you certainly do not have to touch high-tension lines to get a huge shock. I would stay well away, frankly, the high-tension lines running across the Muncie site concern me when I am on the 600x600 pad, although that has proven OK to date. That's about 500 feet separation. Err on the side of caution.
     Brett

[Peter Nevai]

15' is a bit too close, why? Even though the local distribution lines carry about 480v. And do not pose the voltage induction hazard, you have to take into account for you moving about in the circle. Say you loose tension at some place in the circle and need to back pedal to recover the airplane. With only 15 feet of wiggle room you may find your self flying the model right into the power lines. Maybe you need to step back a bunch to compensate for wind. I did something similar in a tight parking lot. Except I nailed a lamp pole when I had to back pedal to regain line tension. I know finding flying spots are getting more difficult but it does not make sense to take unnecessary risks. 15 feet is too close in an imperfect world.

[Dan Berry]

15 ft is too close for local distribution lines. High tension lines would've already been a problem at 15 ft.
Less than a hundred would make me uncomfortable.

[Paul Smith]

A flyer got killed by flying too close to 43,000 volt lines in our city.  Obviously, no more flying in that park. I can't say exactly how close he was, but he sure didn't hit the lines.  They jumped something of a gap.

Maybe some of the E-flight experts on the site can produce a precise table of distances, taking into account humidity and the surface you're standing upon.,

[Gerald Arana]

Did the plane hit the power lines or did a spark jump over the gap? Not talking about high towers just domestic poles. Plane will fly @ 15' only.

I was only 8-9 years old, but that stuck in my mind forever! I don't know if it was a hit or a gap jump. I can tell you it was right across the street from the boardwalk here in Santa Cruz......

Jerry

PS: You've been warned.................several times!

[Arlan McKee]

You guys are a little low on your voltages. I know in commercial areas of Memphis that the lines you see mounted on wooden poles are around 5500 volts. High tension lines here are in the 350K range.
I once worked with a company that loaded barges with freight on the Mississippi river. They used a crane to carry the lids to the barges over to a welding and repair area. They decided to send the crane down the street to another building and the guys drove it without lowering the boom. They hit 350K high tension lines which grounded through the static chains that drag the ground on most equipment. It blew a hole in the street big enough to drive a car into.
A hundred feet would be too close for me.


Arlan

[peabody]

Back in my motorbike store days, a guy had a pretty good burn on his hand, elbow, hip and foot. He was flying his brand new flight streak at a Navy base with the circle center 500' from power lines. First flight was okay. The second flight, as he was flying high (I'm thinking in more ways than one), current jumped to the plane, down the lines, through the handle, his hand, then out his elbow to his hip and then to his shoe.
He tried to get out of the Navy, and then they investigated and found that he was, in fact, about 500' from the power lines. Never let him out.
He brought the Hot Rock by one day.....it had melted into a pistol grip looking thing.
Kinda made me wonder....
I pay attention.

Have fun!

[Fredvon4]

No matter the Voltage or current rating, remember the power lines are Alternating Current at 60 Hz

The magnetic field (exponentially bigger for the High tension lines) expands and collapses 60 times a second

The two conductive flying lines actually describe part of a transformer if they move within the magnetic field. Thus a voltage of varying strength will be induced on the lines

Also beware that the minimum safe AIR GAP distance is greatly reduced in humid air

There are formulas for determining the minimum AIR GAP or non air separation for a given voltage and type of dielectric

and from my Amateur radio learning as well as all the electronics military training; I know that you can get pretty close to a high KV source and NOT have an arc over. Line men work on live lines all the time in pretty close proximity but there is a safe distance for them...and still they die all the time

The height of the poles , separation of the lines,  and insulator length and types, give us clues that the AC will not arc down and fry us within 40 or 80 feet ( typical heights in most communities)

The cautions for 100' ~ 200', or greater, separation for conductive line flight ---is a good, all be it super cautious, safety margin of well over 100%

I have nice property, 2.5 acres with enough (tree free) room for 1/2a to 70' flying ----but can not, or more to the point, will not use for flying my models.
 Because three of my four boundaries have 3 phase legs ON my property line all under 100' of any circle I could set up

Even GSUMP is conductive when wet....just not worth the risk

[FLOYD CARTER]

Ionization of dry air at STP (standard temperature and pressure) is 75000 Volts/inch.  That theoretically says you can come within inches of high voltage lines, but this is not a good idea.

[Brett Buck]

No matter the Voltage or current rating, remember the power lines are Alternating Current at 60 Hz

The magnetic field (exponentially bigger for the High tension lines) expands and collapses 60 times a second

The two conductive flying lines actually describe part of a transformer if they move within the magnetic field. Thus a voltage of varying strength will be induced on the lines

Also beware that the minimum safe AIR GAP distance is greatly reduced in humid air

There are formulas for determining the minimum AIR GAP or non air separation for a given voltage and type of dielectric

and from my Amateur radio learning as well as all the electronics military training; I know that you can get pretty close to a high KV source and NOT have an arc over. Line men work on live lines all the time in pretty close proximity but there is a safe distance for them...and still they die all the time

   In addition, there is the corona discharge issue, which can cause local changes in the usual voltage gradient, which causes build up of charge in the antenna, er, lines.

    Some transmission lines are actually HVDC, which still can have corona losses if the wind is blowing although not as much as AC transmission lines. There are many advantages to long-distance DC distribution, and the problems with it back during the "current wars" (like the difficulty in conversion from AC to DC and back) are now soluble. For some applications the power lost converting it is less than the power lost from corona or other issues with AC, and it permits interconnection between different grids (which would otherwise have to be phase-synchronized between the grids).

    Point being, an arc-over is not required, there are plenty of other possible charge sources and charge transfer mechanisms that are sufficient when that kind of energy is around.

     Brett

[Dane Martin]

This is what we use on boom lifts and AWP's at work.

[Fredvon4]

Any one old enough to have helped dad remove, take to drug store, test, and buy new TV tubes?

Remember him pointing to the big black thing with a spark plug wire going to the back of the Tube, and saying stay the hell away from that bugger!?

Fly back transformer---- and IT would bite you very very badly if you got close enough...

Also trying to dissipate the Capacitor charge was a good way to snuff 3 or 4 good tubes and make the tip of the screw driver useless

My Son is a Master electrician for a huge Austin company doing big stuff ---very high end Billionaire homes, and super sized commercial projects....He Does NOT screw around with electricery

I am Dad trained, then Army trained, and (self) Armature radio trained, PLUS a lot of common sense trained about elecricery...

I do NOT screw with the electrons either... not that I actually learned any lesson from the electric fence----- but can say my brother peeing on  a running Briggs lawn mower spark plug...well you get the idea...

Electrons and/or holes are ALL intent on hurting you if you get too close

Some where in our house, is a Neutral tied to ground... evidenced by slight tingle/vibration when bare foot and touching an appliance like the stove

Son and I, over 23 years, have been searching for it

Most likely is one of the dozens of Florescent light fixtures has a miss wired ballast....  or a ceiling fan (8 of them) ...or a bathroom vent fan, 3 of them....Or attic squirrels chewed enough insulation away to have a slight feedback conductive circuit in the old 14-2 Romex.....very vexing problem

 

[Brett Buck]

Any one old enough to have helped dad remove, take to drug store, test, and buy new TV tubes?

   I ran a tube tester yesterday afternoon! Bad 12SQ7 tube, got a new one out of the bin, $4.


     Brett

[Fredvon4]

Well a total hijack but what the hell

12SQ7 Double Diode-Triode   Audio Frequency   

Brett where do you have access today for a TUBE tester?   

I have not seen one in 20 years.... and have to do pin to pin testing many times creating a holder and circuit to add V or some load

I seem to recall you do antique radio repair

[Brett Buck]

Brett where do you have access today for a TUBE tester?   

  Halted Electronics in Santa Clara, plus they have rack upon rack of NOS and used tubes. I actually have my own tube tester, but it needs to be repaired and refurbished, and I haven't done anything with it aside from put it in my storage unit.

   They aren't all that useful or helpful. Tubes are very reliable by themselves, and don't degenerate just sitting there, and if you have a problem, just subbing in spares and testing voltages can usually reveal the bad one.

    Brett

[Clint Taylor]

I drill water wells and service pumps, and so must work around power lines on a regular basis.  In my area (Carlsbad, NM) primary lines are 7200 Volts.  The primary lines and high tension lines are bare aluminum.  The safety training I have been to usually says to stay 20' from primary lines with a pulling unit.  My mast can go up 47'.  I fly my control line planes at my house.  There is a 7200 Volt line about 70' from the outer edge of my circle.  I have never had any problem.  I do have a cement board that I stand on while flying to keep me from wandering.

In my industry power line contacts are the number one cause of fatalities.  All modern rigs have warning lights and buzzers that activate when the mast is being raised.  Primary voltages can jump several feet to a ground, but not the long distances mentioned in some of these posts.  I have had to pull pumps as close as 10' to primary lines a few times.  In those cases the utility comes out to kill the power or blanket the lines.  It is not something that I enjoy.

[afml]

" I actually have my own tube tester"
Ditto!
My Dad worked for Bell Systems in PA.
Upon replacing the old relay bays with the new electronics, he was able to procure a Western Electric tube tester.
His last 'post' was to head-up the transition to the newer equipment in the regions smaller offices.
Sure was fun going to the office to 'shoot a case of trouble' at night when he was 'on call'.
Those ladders made a great ride down the banks of relays! Great soldering IRONS too!
Oh, since I contributed to the severe thread drift, the tall round Bell Systems 1/2V dry cells lasted FOREVER when used to start our model airplane motors!
Memories.....
"Tight Lines!"
Wes

[Tim Wescott]

'Lectricity can kill you dead.

Worse, it can half-kill you, and leave you crippled and with medical bills for a good long time until you do die.  This is one of those things where the risk can be very small, but the cost can be very, very large -- so being careful is a good idea.

At a guess, staying two or three times farther away from the lines than their height above ground should do you good -- except I'd get even further away from the really tall towers.  Or read Clint and Dane's posts and make your own decisions.

[peabody]

I reached out to my friend that remembered Dave the Navy guy....they were the main power lines into the big Navy yard in VA....HUGE voltage....
He lost his suit even though the Navy still designated the site as a model airplane flying site. Go figure.

[Garf]

All the warnings on the lines, handles, and plans showed a minimum of 200' seperation between the airplane and power lines. That still doesn't apply to getting static shocks from nearby thunderstorms. Been there, had that.

[john e. holliday]

Also depends on where in this great land we live in as well as the weather.   Pawnee Rock KS we were getting static shock on any laps above 10 foot from ground.     At the old Gage Park circle in Topeka the power lines were just beyond the trees.

[Air Ministry .]

In the damp you can feel the buzz from H T Grid 100 yards off .

Wooden Handle and Lightning 4 - 5 miles off , a finger on the lines gets ' a tingle ' .

New .018 laystrate , a Aluminum Handle & Bare Feet , noticing a transformer up a post about 60 Ft Out When it starts pissing down ,
is too bloody close .
You let out a large sigh of relief when the fuel finnally gives out .

[Air Ministry .]

It can jump 60 Ft from 12.000 volt Lines .They say . Thatd be with a trace of humidity .

Aeromodeller MAg in England had occasional reports of 12 Yr Olds geting electroplated
on vacant lots when they hit overhead lines .

One Had a guy scorched with severe burns in places & roasted gumboots .

Left Hand to Right Foot , is ' Thru the Heart . So left handed guys start hopping on your left foot , if it starts raining and your to close .
Or change hands .

[Clint Taylor]

When you look at a power line just remember that the taller it is, the higher the voltage.  Primary lines are the 7200 Volt lines that bring power from a substation to your home.  Your transformer knocks this down to 230 Volts/2 legs to your home.  These low voltage lines are insulated, but it is not a good idea to touch them.  When you look at a primary line notice that the distance between each conductor.  If the current could really jump 20' during humid times, none of these lines would work.

Really tall pylons carrying power cross country from generator stations or hydroelectric plants can be running a million volts or more.  The problem the utilities deal with is wire size.  To move huge amounts of current requires extremely high voltage to keep the wire size down to a reasonable diameter.  I install water well pumps, and pumps of more that 10 Hp are always three phase, and usually 460 Volts to keep the wire size down.  Some gas compressor motors in my area are 10,000 Hp.  These huge motors run at 7200 Volts, three phase.

[Paul Smith]

This is what we use on boom lifts and AWP's at work.

To correctly use this table you need to know the voltage.  Who really knows the voltage of an elevated wire?  I would assume that it's over 440 v.

In our city a cement worker "touched" a power line with the end of the 25' handle of concrete smoothing tool.   He got zapped and was saved by a truck driver.  Universal Ambulance took him to the hospital where he recovered fully.  The local Fire Department claimed that they resurrected him from DEATH caused by 29,000 volts.

It was my contention that no power company puts 29,000 volts 25 feet over a residence.  I think he got a small induced zap from 220.  If he touched 29,000 volts with an aluminum pole he would have looked like an overcooked piece of bacon.

Point being:  you don't really know the voltage.

[Eric Viglione]

I saw an electrician slip and drop a big 1ft flat head screwdriver into a 3phase bus box once. The screwdriver litterally evaporated, no remains to be found other than a small piece of the insulated handle. Sounded like a shotgun blast.

I also met a man once that was involved in an insurance claim.... he was trimming trees across the street from a power substation,.working from the roof of the next building with a pole saw. The spark jumped over 150ft. It evaporated both his arms up to the shoulder sockets and he lived...but not too happily.

I've lost count how many times I was hit by 27k to 30k volts working on tube televisions back in the day. Fortunately it was at low amps. Still hurt like the devil, and the muscle reaction is often worse than the shock itself. I learned to keep the wall behind my workbench clear of pointy things, and even thought about padding the wall once. Heh heh. High frequency voltages in high watt trasmitters can drill a hole in your finger faster than you can blink.. right through fingernail and all.

Yes, electricity can jump large gaps with no obvious reason to the naked eye. Maybe your groundwater table is high that day, dew on the grass, dry air and static discharge, whatever. Respect the voltage and keep the reccomended distance.

EricV

[dave siegler]

If you want to get a feeling for how much voltage is being carried on the lines look at the insulator disks.

the size of the insulator will tell you the voltage.  Otherwise the tower would ground all the current. 

My friend as a utility line guy use a rule of thumb for determining the number of porcelain/glass suspension disc insulators: 10kV for each disc (standard 5-1/4' x 10").

For typical system voltages in North America, this would be:
69kV: 4-6 discs; 115kV: 7-9 discs; 138kV: 8-10 discs; 230kV: 12 discs; 345kV: 18 discs; 500kV: 24 discs.

[TigreST]

I think I've told (typed) this story before.  Circa 1977-ish, Grade-12, Pease AFB New Hampshire.  Flying the Sterling P-51 profile/Fox-35 in the school yard with my brother.  We can see a storm front moving in but it will not be here for some hours,....at least that's what we think.  Hot very humid and over cast on this particular afternoon.  The flying site is bored on three sides by telephone and/or electrical power wires (hmmm...why do we call them telephone poles?).  Very shortly after launch my brother starts pointing at me...or something behind me, or so I think.   I only see him standing in the pit area and have no clue what he's looking at until I rotate to face him again.  I shrug my shoulders in a "What?" manner..then he points at his head with both hands in a "your hairs standing up" type movement.  About that time I start feeling something coming through the E-Just handle....electrical shocks.  It starts getting worse and I signal him to throw a rag in the prop of the plane as I come by him.  It take about three laps to make this happen.  I crash land the Mustang..no damage, and we start packing up the gear. The front was moving much quicker then we first thought.  I'm not sure what it was...hydro wires or storm front that caused the shocks.  One of the weirdest experiences ever c/l related.   Act of god type rained followed shortly after we got home.

T.

[Fredvon4]

lightning is particularly dangerous, because it frequently strikes away from the rain core, either ahead or behind the thunderstorm. It can strike as far as 5 or 10 miles (8 or 16 kilometers) from the storm, in areas that most people do not consider to be a lightning-risk area.

If you do try to use a Flux Capacitor (FC) for in flight battery recharge on your Electrickery model; Remember, you need a power input of 1.21 jigowatts (gigawatts) to operate... I assume flying in lightning may promote proper FC transfer of power

[jim gilmore]

1. I did not read every post so i might be repeating something.
Fly as close and you need to but as far away as possible. In dry air static electricity can build up and just quite far. So the further away the better. I myself would say no closer than 400 feet to high tension lines. and 100 feet to regular power lines. Always wear decent rubber sole shoes and do not fly anywhere near power lines if your standing in wet grass.
 

[Target]

If you do try to use a Flux Capacitor (FC) for in flight battery recharge on your Electrickery model; Remember, you need a power input of 1.21 jigowatts (gigawatts) to operate... I assume flying in lightning may promote proper FC transfer of power

But doesn't the plane have to reach exactly 88mph to enable the FC? :-)

[Fredvon4]

For time travel back to the first VSC or Nats you need Tim's TUT with the settable clock mod, and yes 88MPH

[Jim Kraft]

It is more the induced voltage from the flying lines getting to close to the power lines than a voltage jump as said above. I was flying in a contest in Topeka where there was a thunderstorm about 5 miles away, and every time I got above level flight I got zapped. I flew the tank out at 4 ft. Never again.

The bad thing about being hit is it might not kill you, but can get your heart of sync. There have been many cases of that where they have to stop your heart and restart it to get it back to normal. I worked around 440 three faze for many years, and I have great respect for what can happen. Heard to many stories at safety meetings about bad things. I also worked around 1400 lb. pressure gasoline and diesel pipelines and pumps. We used 500 horsepower electric motors to run the pipeline pumps.

Between the high voltage and the high pressure gasoline, you do not make many mistakes, and I worked alone almost all of the time. After 27 years I retired and did not realize how much pressure I worked under until then. Keep away from power lines at least a 100 ft, an you will be OK.