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hypothetical grounding question
ok guys something we were discussing today, kind of a "what would you do", 69kv line, stacked construction, bottom insulator is bad, air break switch open on both sides of you, you have to climb to fix it, how bad of an idea would it be to test and ground just the bottom phase you are working on as opposed to all 3? just wanted to hear your answers.
Okay, you aren't telling us if this 69kv line runs parallel to any higher voltage transmission lines where you might be getting some induction. Another 12 to 15 feet of climbing up you can grd. them all. I know how heavy those 4/0 grounds are to carry and I have done it. You probably have a Polaris Ranger and can drive right up to your job. Me I would ground all three phases.
polaris ranger, thats funny.Originally Posted by Highplains Drifter
.. no possible induction, i know ground all 3 is the right thing to do but what could be the possible hazzards in grounding only the one you are on in this situation?
I guess sometimes the things we cut corners on can sometimes bite us in the butt when we get older. I have cut lots of corners myself, but there are lots of young inexperienced folks reading these posts. And they will try cutting a corner with out knowing totally what they can get by with. So I guess in my older years I just figure it is as easy to do the job correctly then openly discuss the short cuts. Let the young ones learn what they can get by with themselves without us telling them.polaris ranger, thats funny.
i totally agree with you 100% on teaching the next gen the correct ways to do things without cutting corners, some of the corners that i have seen cut, and yea, also cut myself over the years were a little scary. i was just trying to settle an argument at work betwene some of us about this situation.
What if the switches on either side of you happpen to be bad,,,,no grounds means ZAP.
Done it so many times I can't count.... It's your life, every situation is different.
There ain't much that can go wrong if confirmation of switch opening is confirmed and you ground your conductor. If your not climbing over another to get to the one you want, I don't see any issue.
I too have been guilty of this short cut in the past. The problem is the maximum fault current that can be developed on a circuit! If you have a visual opening on both side of you, and you ground the phase you are working on in an equal-potential way you stand a chance of surviving if a fault occurs, BUT it is not optimal.
An accident investigation was performed several years ago where a similar work situation was taking place on a 115KV line with parralel transmission lines. A fault happened on an ajacent line when they were switcthing for an unrelated issue. The switch broke when switching the other line creating a hugh fault current. The fault current was induced onto the 115KV line. The single ground the guys were using from the ground on the pole to the phase they were on, burned off at the pole ground connection. The pole ground burned off above the ground jumper connection which energized the pole ground. The Groundman running the hand line was shocked, and went to the hospital in bad shape. The two up top felt it but were on dry wood so nothing major happened to them. The Groundman luckily survived but did not go back to work for a while.
This could very well have been a multiple fatality but the very dry conditions saved them.
When you take a short cut you are not doing anyone any good.
Grounding all three phases is the best insurance should the line come hot the protection device will see it and trip.
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