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| Underground Manhole Systems https://brainfiller.com/arcflashforum/viewtopic.php?f=13&t=379 |
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| Author: | wmok82 [ Fri Mar 20, 2009 9:10 am ] |
| Post subject: | Underground Manhole Systems |
All - What are you guys doing with respect to your UG manhole systems? Specifically, if you have calculated energies, what are you doing with PPE? |
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| Author: | stevenal [ Wed Apr 01, 2009 12:06 pm ] |
| Post subject: | |
http://standards.ieee.org/nesc/NESCIR557.pdf Deenergize, mainly because of cable movement during a remote fault. |
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| Author: | acobb [ Wed Apr 01, 2009 2:35 pm ] |
| Post subject: | |
One other issue to consider. Years ago I was in a small vault checking on some equipment when I noticed a portion of cable had "blown out" at some point allowing an energized 7,200 volt aluminum cable to be exposed. Somehow it was still operating. Didn't hang around very long! |
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| Author: | haze10 [ Wed Apr 01, 2009 5:29 pm ] |
| Post subject: | |
Enter manhole in HRC4. Check all cables with tic tracer. No live voltage found exit manhole and re-enter in HRC2. De-energizing is often not practical. How many square miles of city is it acceptable to de-energize before inconvienence become infeasible? Most manhole accidents to not occur because there was a conincidental fault on an adjacent cable. Most are from touch an energized conductor, by accident. |
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