dangerous current

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normbac

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could someone explain how dangerous currents can occur when you use a 3 wire to a panel from a separate structure main panel say there is no metal conduit between the two structures but there is a say phone or coaxial cable joining the two structures how would one get shocked if you could explain a scenario I am sure I would then understand it. I know it has changed in 08 and I am figuring it must have been a serious issue to have the NEC pay attention. Thanks
 
normbac said:
could someone explain how dangerous currents can occur when you use a 3 wire to a panel from a separate structure main panel say there is no metal conduit between the two structures but there is a say phone or coaxial cable joining the two structures how would one get shocked if you could explain a scenario I am sure I would then understand it. I know it has changed in 08 and I am figuring it must have been a serious issue to have the NEC pay attention. Thanks
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It's not shock (primarily), but the possibility of forcing some of the neutral current through those other conductive pathways.
 
LarryFine said:
It's not shock (primarily), but the possibility of forcing some of the neutral current through those other conductive pathways.
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How would that current get on to a phone line?
 
ptonsparky said:
The direct bury phone line has a metal jacket that should be bonded to the building GE and would create your additional path.
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Sorry still not understanding are you saying that the main phone line from the street can become a GEC and if so where does it become energized by the neutral since it is a separate system from the electrical system
 
normbac said:
Sorry still not understanding are you saying that the main phone line from the street can become a GEC and if so where does it become energized by the neutral since it is a separate system from the electrical system
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The copper sheath of that phone cable, or the shield of a coax cable is required to be connected at both buildings to the grounding electrode system, if the neutral was also bonded at both buildings that would place the copper sheath or the shield in parallel with the neutral conductor and they start carrying current.
 
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