Electrocution by neutral and ground?

[michaeltay]

Hi:
A man was salvaging (stealing) copper wires from an abandoned building with 3-phase power supply (415V). He cut several neutral and ground wires (black and green/yellow) at the main service panel and was electrocuted (died). The other phase wires were not cut. How is this possible? Thanks in advance for your pointers.

Mike

 

[bphgravity]

Re: Electrocution by neutral and ground?

Where are you from? Your nominal voltage and conductor colors are not US typical.

When you open a grounded (neutral) conductor, it becomes an ungrounded (phase) conductor and will have a potential of whatever the phase voltage is to ground or line voltage to another phase.

What kind of science are you in?

[ May 31, 2005, 08:19 PM: Message edited by: bphgravity ]

 

[michaeltay]

Re: Electrocution by neutral and ground?

Hi:
My background is chemistry and chemical engineering. I am from Singapore. The victim was an electrician who had done wiring jobs for years. There were black marks on both his hands and he was thrown backwards. Thanks.

Michael

 

[charlie b]

Re: Electrocution by neutral and ground?

I have one more possible explanation for the situation you have described. I won't say it is likely, but it is possible.

In a balanced, three-phase system, the neutral carries no current. But such systems are seldom completely balanced. An imbalance causes current to flow through the neutral. Perhaps while cutting the neutral, the person might have had contact between his hands, the cutting tool, and the neutral wire that was being cut. That would put his body in a parallel circuit: current would flow from the netural to the tool, to his hand, through his body, to the floor, via metal flooring or even via dirt back to the ground rod, and from there back to the source. It would not take much current to be fatal.