Electrostatic charges on a bare wire stretched in the air? 1

[Sempronio1960]

A bare wire stretched in the air, in particular the conductor of a power line taut between their supports on its isolators, and never fed, without any type of electrical connections at the ends, can be the site of electrostatic charges? If so, why?

 

[Skogsgurra]

Probably because of the electrostatic field that easily is several kV/m.

But probably not anything you will ever be able to notice.

Gunnar Englund

http://www.gke.org

--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

 

[Marmite]

If the line runs in parallel with other lines over any part of its length it will also pick up a charge by mutual induction.
This is why utilities normally earth redundant, or out of service overhead lines. Also when you are building a new line, for safety reasons, the conductors are earthed as they are erected.
Regards
Marmite

 

[Sempronio1960]

>Marmite (Electrical) ... line runs in parallel with other lines ...
There aren't any lines nearby. There was an arc between a metal beam, suspended by a crane under a line in construction never fed, and another beam placed on the ground. The conductors of the line under construction had been grounded at the start of the work near the crane. I think for electrostatic charge accumulated on the beam suspended: is it possible?

>Marmite (Electrical) ... building a new line ... the conductors are earthed ...
As you earthed conductors in buildings new lines? Every how many meters?

 

[waross]

Many years ago I was appointed safety ban on a project to insert capacitors in series with a 500kV line. I was given an information package of accident investigation reports.
One report related an accident on a line under construction:
The new line was grounded at both ends. Some distance away from the construction site the line ran parallel to an energized line.
At the work site the line was grounded and the crane was also grounded but the line ground and the crane ground were not interconnected.
The crane lifted a worker up in a man basket to do something on the line. When the worker touched the line he received a shock which rendered him unconscious. Fortunately he survived.
Another instance later involved a friend of mine. Similar situation; A line grounded at both ends but parallel to an energized 500 kV line. The men were working near the ground connection.
Somehow the ground connection went open and one worker bridged the gap. He died. My friend was blown out of the bucket he was working from and received serious back injuries.
Google 'step potentials' and 'touch potentials'.
When an un-energized line is in proximity with an energized line a potential may be induced. Multiple grounds may result in a circulating current of several amps or more. This current returns through ground and may cook the ground around the ground electrodes resulting in the resistance to ground rising to an unacceptably high value.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[Sempronio1960]

>waross ... When an un-energized line is in proximity with an energized line a potential may be induced. ...
In these cases would be the induction magnetic, not electric. Right?

>waross ... Multiple grounds may result in a circulating current of several amps or more. ...
In these cases it is better to just put a land close to the workplace without creating loops. Right?

However in my case there were no near energized lines.

 

[marks1080]

It's possible and should be anticipated... In your scenario the line is acting like a capacitor.

 

[jghrist]

If there were no energized lines nearby, then most likely the beam got charged with static electricity similar to how you would get charged shuffling your rubber soled shoes on a carpet then touching a doorknob.

 

[Sempronio1960]

>marks1080 ... acting like a capacitor ...
>jghrist ... the beam got charged with static electricity ...

I have some difficulty imagining the physical phenomenon. The beam suspended and that placed on the ground are both conductors (not dielectric as rubber etc.) and not connected to emf, so they can charge only if immersed in an electric field, the origin of which I can not find it anywhere.

 

[electricpete]

Think about this: how does a cloud get charged to produce lightning?

It happens.

The only way to assure something won't hold a charge is to ground it.

=====================================
(2B)+(2B)' ?

 

[waross]

In the early days of PLCs, on a major project, all the MCCs came wrapped in plastic. When they were to be installed the easiest way to remove the plastic was to raise the MCC a few feet in the air using a crane and fabric slings. The plastic sheets would be torn off the MCC and the crane would continue and place the MCC.
We had hundreds of interface cards destroyed and replaced. Do you think that it may have been a static charge generated when the plastic was removed?

In these cases would be the induction magnetic, not electric. Right?

Anywhere near a 500 kV line there is often a lot of capacitive induction also.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[Sempronio1960]

>electricpete ... how does a cloud get charged ...
The clouds get charged by friction between particles due to convective movements. I don't think clouds are comparable to conducting bodies. However I will ask more information about environmental conditions.

> waross ... Do you think that it may have been a static charge generated when the plastic was removed? ...
Yes, I do!

> waross ... Anywhere near a 500 kV line there is often a lot of capacitive induction also. ...
As here, on the nail?

http://www.eng-tips.com/viewthread.cfm?qid=295758

 

[PersonalProfile]

Yes for various reasons as cited above + :

http://en.wikipedia.org/wiki/Aurora_borealis#Auroral_events_of_historical_significance

One of the examples provided from Waross, sounds suspiciously like the circumstances of the following:

http://www.townsvillebulletin.com.au/article/2009/12/07/98781_news.html

Regards,
Lyle

 

[stevenal]

The clouds get charged by friction between particles due to convective movements. I don't think clouds are comparable to conducting bodies. However I will ask more information about environmental conditions.

Would you accept the aluminum skin of an airplane as conducting body? Link

 

[DRWeig]

Google up a triboelectric series. Here's one for you: Link

Best to you,

Goober Dave

Haven't see the forum policies? Do so now: Forum Policies

 

[bacon4life]

From the Hicks Health and Safety Mobile Crane manual:

Before working with loads in which a static charge can be induced (such as lifting plastic pipe), the following precautions shall be taken when necessary:
o Provide the equipment with an electrical ground directly to the upper rotating structure supporting the boom.
o Attach a grounded jumper cable between the material being handled and the boom.
o Remove flammable materials from the immediate area before operating the crane.


This wasn't a sky crane by chance? Helicopters induce a very big static charge in suspended loads.

 

[itsmoked]

Blow reasonably dry air across an insulated wire and you will deposit charge. It's no different than water dripping thru rings (Lord Kelvin generator) or a Van De Gaff generator with the motive power for charge separation provided by the wind instead of a motor.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[cranky108]

This might be the same thing Tesla saw. He proposed using a high voltage spark gap connected to a reverse Tesla coil to convert the static charge to a lower voltage with a higher current so it could be used to do work. Sadly Tesla's ideas were dashed when he lost his source of funding, mainly because there was no way to make a profit from free electricity.

On the other hand, if your source of energy can be shown to come from induction, or capactiance from a power company, you can be arrested for stealing energy.

Make sure of you energy source. AC or DC?
AC is from a power company.
DC could well be a static electricty.

 

[ghostbuster7]

Farmers have been placing large steel coils of fencing on the ground under the powerlines for years and dragging them into the barns at night to keep their livestock warm.

 

[Sempronio1960]

Thank all for your answers. Greetings with this link:

http://mappingignorance.org/2013/05/09/on-bees-antennae-and-electrical-flower-power/