Dar Sir,
What is farady's cage & how it works

Let me google that for you (http://www.lmgtfy.com/?q=faradays+cage)

You will find:

http://en.wikipedia.org/wiki/Faraday_cage

Here's an example:
Helicopter High Voltage Cable Inspector (http://www.flixxy.com/helicopter-cable-inspector.htm)

Now those guys earn their money.