Thats typical of Electric trolleys in small 8 foot track drifts. And the mining act covers that sort of installation not the electrical code. The reasoning is its not practical to put that trolley line any higher. That and people are trained to work around them.
WE work under the 3 foot restriction now, anythi ng 600 or above must be 3 feet from a miner or in my case 1 foot from an electrician.
Another consideration is the amount of available fault current the rectifier station can provide AND the GF protection on the line ( will trip if there is short to ground ). On the 1000 volt Kiruna trolley system that trip point is around 10 mA ( generaly non leathal shock )and thats quite a feet to keep a system that sensative from tripping in normal opperation ( just dust and dirtt can set it off ). Most of other lower voltage systems use .5 to 4 amp trip setting ( possibly leathal but not from burns. Its generaly the burns that kill ).
You can be killed by 4 amps no doubt but I am living proof that more often a fuck up ( and even I fuck up with all the training and safety beat into me and touch something live. After all it is broken or malfunctioning when I am called in the first place) results in a lot of bad words some pain and some burms. I have had 3 or 4 " fuck ups " in my life only 1 serrious that burned me and 1 near miss with some very leathal 13800 v switch gear. Mostly this happened because I had not arc flash protection and was not provided with rubber gloves
and because I did hot work ( testing on live equip or actualy working on live equip )....
Hot work is now against the law for the most part because it is dangerous and todays power system pack not just enough power to cook you but enough available energy to super heat the air and turn an electrical box into a bomb. And those bombs have killed people. Testing and working around but not on live equipment is restricted. Hot work can only be done by permit that explains why it can't be powered down.
http://www.youtube.com/watch?v=MH1_gjPTMIg&feature=relatedDoesn't look violent does it but its hotter than the sun at the center of that fire ball and metal has turned into a gas
I have taken that ride on the infinit bus
I have the scars to prove it.
What is safe or dangerous is realy all in the eye of the beholder at the end of the day. That poor fellow in the video probably had no idea that wire was there and never mercifly knew what hit him.
