Electric shock through a tree touching a high-tension wire

[ElectroEnthusiast]

Few days before, i had a daily wage worker to pluck some coconuts from a tree. A part of tree(branch/leaves) was touching to an high-tension wire that carried some high voltage(maybe some kV).
When he climbed the tree and when he was at the peak of the tree, he said that he felt an electric shock. The question is: ' Would this cause an electric shock?( Since he was standing on the tree, and was by noway touching the ground directly(also with any conductor or anything).
What seems to me is that he is at the same potential(as he's on a tree), i suppose he acted like that to attract some extra payment from me(since i would feel that he did the job with some extra risk).

 

[jpanhalt]

Re: Electric Shock: Tree

If the top of the tree is touching the HV line and the base is touching the ground, there would be a voltage differential along the length of the tree. Now, if you climb it, say with your hands a meter or so from your feet, one could be shocked by that differential. That is why it is recommended to keep one's feet close together (e.g., shuffle) when walking away from a downed power line.

John

 

[ElectroEnthusiast]

Re: Electric Shock: Tree

If the top of the tree is touching the HV line and the base is touching the ground, there would be a voltage differential along the length of the tree. Now, if you climb it, say with your hands a meter or so from your feet, one could be shocked by that differential. That is why it is recommended to keep one's feet close together (e.g., shuffle) when walking away from a downed power line.
John

Hi joHn,

What i mean in the question is, the person has already reached the top of the tree. And he then says: He felt the shock(At the Top of the tree).

 

[FvM]

Re: Electric Shock: Tree

The observation sounds reasonable, because part of the high voltage can be expected to drop along the tree, due to the finite conductance of the wood. It's hard to estimate the voltage drop's magnitude. I guess, you don't want to try an experiment?

Normally, the electricity company is in charge to cut the touching branches on their own.

 

[Rob B]

Re: Electric Shock: Tree

Should have Sensitive Earth Fault protection .

An incident occurred in the UK recently where two horses appeared to be electrocuted at a race track, possibly by an underground cable fault.

Here's the link:

http://www.bbc.co.uk/news/uk-12497064

 

[jpanhalt]

Re: Electric Shock: Tree

Here is one link among several that describe safety around high voltage and trees.

**broken link removed**

The question of hopping vs. shuffling has been discussed. Some people have recommended hopping on one leg. Clearly, that is unstable for most people, and falling on one's hands while trying to hop on one foot would be one of the worst positions to be in. As for a two-legged hop, there are probably situations where that is necessary, as in jumping from a step onto the ground, but once on the ground, most people are less likely to fall if they shuffle.

John

 

[FvM]

Re: Electric Shock: Tree

Should have Sensitive Earth Fault protection

I'm not familiar with power districution standards, but I guess, that it's impossible to detect a small earh fault at an overland line. In the said case, the earth currents may have been rather low, no injuries have been reported. As John showed in his instructive link, there are other cases to be considered.

 

[Rob B]

Re: Electric Shock: Tree

I'm not familiar with power districution standards, but I guess, that it's impossible to detect a small earh fault at an overland line. In the said case, the earth currents may have been rather low, no injuries have been reported. As John showed in his instructive link, there are other cases to be considered.

It might not operate with a phase touching a tree (moisture dependent maybe?) but it is designed to detect in the low mA region.

 

[KJ6EAD]

Re: Electric Shock: Tree

The term I've been taught for the phenomenon is "step voltage" or "step potential" Earth potential rise - Wikipedia, the free encyclopedia.

 

[ElectroEnthusiast]

Re: Electric Shock: Tree

Normally, the electricity company is in charge to cut the touching branches on their own.

Yep, they cut it like about a week ago, but the incident happened before that.

Sensitive Earth Fault protection

How can you have it for a tree/horses?!!!

So wont the plant cells get toasted due to that voltage? But the plant is still standing tall, i guess it had enough cells to keep multiplying.

 

[jpanhalt]

Re: Electric Shock: Tree

So wont the plant cells get toasted due to that voltage? But the plant is still standing tall, i guess it had enough cells to keep multiplying.

The perception and effects of shock on animals is through our nervous system. Plants don't have a similar system. Both plants and animals can get toasted, if the current is high enough. Obviously, that was not the case here.

John