Power Lines

[kmr2288]

There is playgroung and baskeball goal equipement located under power lines. I'm getting electrical charges from the metal of the playground equipment. There also is an electrical power distrubtion station located acroos the street from the playground. is it possible to have stray voltage in the ground or the power lines my problem. Is there anyway make the equipment safe.

Thanks Ken

 

[jeremysterling]

"I'm getting electrical charges..."

What does this mean? Is it measurable? With a DMM?

Privately/school owned primary overhead?

If these electrical installations/lines belong to the utility they should be involved in an investigation.

 

[mjf]

I would probably report your concerns to the poco, requesting, as jeremysterling said, that bthey investigate.

 

[Cow]

I've serviced some light poles too close to power lines for comfort. I can turn a glowstick on, stick it in my back pocket and reach out and touch the fixture(with no power to it) and the tester goes off in my pocket. You get one heck of a zap if you're not wearing gloves!

 

[hurk27]

Capacitive coupling is always a problem for metal items under medium voltage power lines, and this is one place a ground rod can help, but make sure you bury it and not leave it sticking out of a ground for someone to fall on, bond anything that might have a build up of voltage to it, I have done street lights under a power line and all I had to do was bond it with a wire to my 1' long screwdriver stuck into the ground while I was working on it, once the circuit was ran to it and connected it went away.

 

[hurk27]

I've serviced some light poles too close to power lines for comfort. I can turn a glowstick on, stick it in my back pocket and reach out and touch the fixture(with no power to it) and the tester goes off in my pocket. You get one heck of a zap if you're not wearing gloves!

Back when tic-tracers had just came out, I was in a house trying to use one to trouble shoot a house we had on generator, the thing just went nuts, no matter where I put it, it would just beep away, well I thought it had a bad battery so I went out to my truck and changed it, as I held it up it was still beeping just them my eyes move further up and I realized there was medium voltage lines right above the house.

Later on I had to go back to hang lights, and thought I would mess with the guys, we had a few under cabinet lights to mount, so I took a couple of the florescent lamps, and connected them to a 10' piece of THHN on one end, and laid the other end on the SS metal kitchen sink which was grounded through the plumbing, they lit up almost full brightness, I just left them for the guys to find, but what I didn't know was the home owner was in the house, it didn't set well with him when he found out how these two florescent lamps was lighting sitting on the kitchen counter, needless to say I almost cost the builder the sale of the house, it took some talking to not get him to back out, last time I did that trick.

It didn't really matter as the house was condemned a year later because of the home owner getting shocked from almost any metal he touched that wasn't bonded, and there was no way to prevent it from happening on portable items like metal ladders, even his car.

 

[T.M.Haja Sahib]

Capacitive coupling is always a problem for metal items under medium voltage power lines, and this is one place a ground rod can help, .......... I have done street lights under a power line and all I had to do was bond it with a wire to my 1' long screwdriver stuck into the ground while I was working on it, once the circuit was ran to it and connected it went away.

Capacitive coupling is not at work here because the street light metal pole would be buried in the ground and so it is already grounded.So the voltage induced in the metal pole due to current flowing in the Medium voltage lines might be the reason.Providing extra grounding as above with a '1' long screwdriver' might have equalized potential with that on metal pole,IMHO.

 

[kwired]

Capacitive coupling is not at work here because the street light metal pole would be buried in the ground and so it is already grounded.So the voltage induced in the metal pole due to current flowing in the Medium voltage lines might be the reason.Providing extra grounding as above with a '1' long screwdriver' might have equalized potential with that on metal pole,IMHO.

We have either a capacitor or an inductor at work here, which one is more likely?

Isn't an inductor a core and coil? Where is the core, where is the coil?

Isn't a capacitor two conductors with an insulator between them? We have HV line and metal object at grade level as conductors and air between them as insulator.

 

[zbang]

Isn't an inductor a core and coil? Where is the core, where is the coil?

A single straight wire has inductance, and two straight and parallel conductors can form a transformer. The overhead line will induce a current in the pole by its magnetic field; whether it's detectable is a different matter. (The capacitor couples by electric field.)

 

[charlie b]

We have either a capacitor or an inductor at work here, which one is more likely?

Wrong question. We, in fact, have both. The appropriate question is this: Which is more likely to result in a measureable current in a nearby conductive surface?

 

[kwired]

Wrong question. We, in fact, have both. The appropriate question is this: Which is more likely to result in a measureable current in a nearby conductive surface?

I like this response the best so far.:thumbsup:

 

[meternerd]

Have you ever considered that you may be charging yourself instead of surrounding equipment. I have worked in many substations where touching any metal, whether grounded or not, can zap pretty hard. May be the same thing working here. Grounding could make things worse. If that's the case, a ground mat would be the only solution. Just a thought.

 

[texie]

Just happen to see this today: http://videos.tdworld.com/video/Contact-Voltage-Detection

 

[hurk27]

Capacitive coupling is not at work here because the street light metal pole would be buried in the ground and so it is already grounded.So the voltage induced in the metal pole due to current flowing in the Medium voltage lines might be the reason.Providing extra grounding as above with a '1' long screwdriver' might have equalized potential with that on metal pole,IMHO.

was not a metal pole, as the pole was a common wood pole like used by power company. next time I'm out there I'll take a photo if I can remember.

 

[T.M.Haja Sahib]

was not a metal pole,

Then grounding it has no effect....... except at the point where the bonding wire from the 1' long screwdriver stuck into the ground attached with the wooden pole.

.... all I had to do was bond it with a wire to my 1' long screwdriver stuck into the ground while I was working on it, once the circuit was ran to it and connected it went away.

 

[hurk27]

was not a metal pole, as the pole was a common wood pole like used by power company. next time I'm out there I'll take a photo if I can remember.

I was out there today had some free time so I took a few photos of the pole in question:

it was a shocking experience, but not my first one. screw driver worked perfectly until I had the circuit EGC connected

 

[kwired]

I suppose that light absolutely needs to be directly below the transmission lines:slaphead:

 

[hurk27]

I suppose that light absolutely needs to be directly below the transmission lines:slaphead:

well we put it where they wanted it, it its where it is lol

 

[T.M.Haja Sahib]

Hmm.The free charges on a wooden pole can not move as in a metal pole,they stay where they are as the wooden pole is an insulator.Perhaps,was the subject wooden pole moist due to any rain so that the 'screw driver grounding' was effective?

 

[hurk27]

Hmm.The free charges on a wooden pole can not move as in a metal pole,they stay where they are as the wooden pole is an insulator.Perhaps,was the subject wooden pole moist due to any rain so that the 'screw driver grounding' was effective?

Perhaps the part I bonded to the screw driver was the metal light on top of the pole and the conductors coming down it.

Do you really think I would try to bond a wooden pole?

No where in post 5 does it say anything about bonding a pole, I was talking about the equipment on the pole and assumed most would understand that the shocks was coming from handling this equipment and conductors, not the wooden pole, but I guess I was wrong?:roll: