# Working on high voltage power lines

1. Apr 7, 2010

1. The problem statement, all variables and given/known data

We know that current will flow whenever there is a potential difference. Sometimes when there are problems with high voltage lines - workers must work on them 'live' (not shut down). How do the workers manage to work on the wires without getting electrocuted by the high voltage?

2. Relevant equations

N/A

3. The attempt at a solution

If anybody knows how workers are protected in real life, I'd be curious to know.

I do know that if the workers had protective rubber gloves they would be okay to work on the wires because the gloves would insulate them against the flow of current. But, is there something else that high voltage workers use to not get 'zapped'?

2. Apr 7, 2010

### Staff: Mentor

Rubber gloves would not be enough by themselves at those voltages.

Here's a question for you that should help -- why don't birds get electrocuted when sitting on power lines?

3. Apr 7, 2010

Let's see... About the birds, they aren't grounded (obviously). That would mean that when they land on the power line, their potential would become that of the power line, meaning *somehow* they are not experiencing a net current...?

4. Apr 7, 2010

### Staff: Mentor

Not exactly. When you say "grounded", that would mean that they were holding a ground wire in one foot while holding onto the power wire with their other foot (no rubber booties). That creates a voltage (potential) difference across their little bodies, which generates a big current through them and poof!

But what if you had a big bird like a great white heron, who landed on the residential power wires, and had both feet on one wire. What would change when the heron tried to step to the next wire...?

5. Apr 7, 2010

### mgb_phys

And why would you not hand a metal tool to somebody working on a wire!