Sizing Temporary Protective Grounds

[BrkfldEE]

thread238-82004
Does anyone have a clear method to size temporary protective grounds? I have read IEEE 1246 and that doesn't seem to go into enough detail. I have read IEEE 1048 and it references some tables in ASTM F855-1997. However I can only get access to ASTM F855-2009 which doesn't seem to have the tables anymore. ASTM F855-2009 has Table 1 for X/R ratios of 1.8 or less and Table 2 for X/R ratios of greater than 1.8 however I can't understand how to use table 2, it doesn't seem to give enough information. Any help or guidance would be appreciated.

 

[Jebb]

Check out Chance Section 3000 (Grounding Equipment)

http://www.hubbellpowersystems.com/literature/encyclopedia-grounding/pdfs/07-0801-13.pdf

. We size our grounds for the breaker failure clearing time. A few locations require 2 sets of grounds due to high fault current or slow clearing times, which is clearly posted with signs at the grounding locations. The portable grounds should be a short as possible.

 

[bwen08]

I went through this quite a while back but have no idea where I stuffed all the documents I referenced and the calculations for it. Check out the appendixes and references listed in the USBR grounding document as it might help you get going.

http://www.usbr.gov/power/data/fist/fist5_1/vol5_1a.pdf