Fall of Potential Test Alternative

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metallica5

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Metro DC
I have a project that calls for Fall of Potential test OR alternative in accordance with IEEE Standard 81. New School has 1200 amp 480/277 3 phase service. we have 3 ground rods in a triangle 15' apart with 4/0 copper into the main gear. There is also 3/0 to the water main from gear and another to building steel. This is all done per their plans/specs. My first question is: Can a three point test be done while gear is energized? My second question is what is an alternative test that would be in accordance with IEEE Standard 81.
Thank you for help.
 
There is the slope method and the intersecting curves method but those are for large ground systems. 3 point FOP is the correct test here.

Yes it can be done when the system is energized but the ground needs to be disconnected so care needs to be taken to ensure there is not any current on the ground. Your best bet will be to sub this out to a testing company. (Brian John (member here) is in your area and would be an excellent person to contact for this)
 
This project is in the Northeast (far from Brian John and Leesburg, VA). My concern was having to shut down the gear to lift the ground. Although it can be done safely, our policy is to shutdown. I was looking into the possibility of an alternative to the three point test that didn't require shut down of gear. My plan now with your feedback is to shutdown and have third party tester conduct the Fall of Potential test.
Thank You
 
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