Are grounded jacketed cables considered exposed energized parts?

[jtinge]

My question relates to how to work around energized cables in manholes. All of our high voltage cables are jacketed cables with a grounded shield such that the outer jacket is a ground potential. When working on a de-energized cable, is there a minimum approach distance to the other jacketed energized cables and if so why, since there is no exposed potential on the grounded jacket of the cable? An interpretation by the NESC, Rule 410A3 states that the phrase "on or near energized parts or equipment" includes conductors. "Near" implies a minimum approach distance to exposed energized parts. So if the outer jacket of the cable is grounded, how can the cable be considered an exposed energized part? Should I be applying the 70E update of "exposure to electrical hazard" rather than "exposed energized parts"? How do others deal with working around energized cables in manholes?

 

[Fulthrotl]

My question relates to how to work around energized cables in manholes. All of our high voltage cables are jacketed cables with a grounded shield such that the outer jacket is a ground potential. When working on a de-energized cable, is there a minimum approach distance to the other jacketed energized cables and if so why, since there is no exposed potential on the grounded jacket of the cable? An interpretation by the NESC, Rule 410A3 states that the phrase "on or near energized parts or equipment" includes conductors. "Near" implies a minimum approach distance to exposed energized parts. So if the outer jacket of the cable is grounded, how can the cable be considered an exposed energized part? Should I be applying the 70E update of "exposure to electrical hazard" rather than "exposed energized parts"? How do others deal with working around energized cables in manholes?

well, if there's three feet of water in the bottom of the substructure, there's
a good chance that when you pump it dry, you can safely enter the
vault. after you drop a sniffer for a gas check.... which you should do
before pumping the thing out.

 

[infinity]

If something is grounded can it be an exposed energized part?

 

[jtinge]

That's my thought; however, I have seen this particular statement regarding work in underground locations in many requirements docs: "When working on de-energized cables, conductors, or equipment, all exposed energized conductors within reach of any part of the body, shall be covered with suitable protective equipment." Are they classifying grounded jacketed cables (i.e. PILCN) as exposed energized conductors? What conductors are being referred to in this statement?

 

[charlie]

. . . Are they classifying grounded jacketed cables (i.e. PILCN) as exposed energized conductors? . .

I don't know what PILCN cable is but PILC is paper insulated, lead covered. I assume that is what you are talking about.

I have seen the results of a medium voltage cable blowout and would not be interested in being in a manhole when the blowout occurred. One thing that has always bothered me about PILC is that the oil impregnated paper tends to get a bit brittle with age. Assume that has happened to the cable behind you when you brush against it with your . . . :roll: