hI
My friend, an electrician, touches live wires, buss bars, utility non-fused feeders (All 120v-240v) WITHOUT ANY GLOVES
He belives he is safe as long as he has the plastic showes on and he is not touching any conductive materials while he is with contact......
This not right/safe things to do right??
Tanx
I'll start with the basic idea:
It takes two points of contact, with a voltage difference across the two points, in order to cause current to flow and thus damage to the human body. Current can be even more dangerous, if it flows through a path that crosses the heart. You will hear about the "one hand rule", which is that you only handle live circuits with one hand, so that current doesn't flow anywhere near your heart.
It is not the level of voltage that hurts you, it is the difference in voltage across two points on your body. If there is only one point of electrical contact, or two points of electrical contact at identical voltage levels, you could say that the person is figuratively "a bird on the wire". There is no voltage difference across the human body driving current to flow, and therefore the person would be safe.
Just like a bird on an electrical wire. Both of the bird's talons are touching points on the wire that are at 13 kV, and in the same phase with one another. The resistance through the short piece of wire between talons is a lot less than the resistance through the bird body. Therefore, current flows through the wire like it should, and not through the bird.
The same is true, if a person can perfectly insulate themselves, and only handle one phase of one busbar at a time. You very likely can get a false sense of security, because conventional clothing is not a perfect insulator. Even though the shoes and clothing are normally non-conductive, they are not tested to electrical conditions. And if the clothing is damp, it ruins its value as an electrical resistor.
There do exist linesman's insulating boots, that are rated for withstanding 15 kV (or possibly higher) while working on power lines. Much safer than conventional shoes, but not perfect. The person still needs to be careful, not to let any part of their body or clothing, come in contact with a live or grounded part, while working on a live part.