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On 10/21/14, 4:07 PM, Yurtle Turtle via Tesla wrote:
Pics of an industrial fence?
I'll see if I can take some pictures today.
At JPL, we have the same thing. There's a bonding jumper between the
swinging gate and the rest of the fence, for instance.
Here's a site with pictures
http://www.erico.com/newsdetail.asp?newsid=71
and a spec I found
https://www.wbdg.org/ccb/DOD/UFGS/UFGS%2032%2031%2013.pdf
3.19
GROUNDING
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NOTE: Delete this paragraph if grounding is not
required. If grounding is required and lightning
protection is not part of project design, the
requirements in the second set of brackets will be
used in lieu of those in the first set of brackets.
Provide fence grounding details when composite type
posts are specified where grounding of the fence is
required. Grounding requirements may be indicated
on the drawings or included in this section.
Specify polyvinyl chloride coated fencing with care
when grounding is a project requirement.
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Ground fencing as [indicated on drawings][and specified].
[
Ground all fences crossed by overhead powerlines in excess of 600 volts,
and all electrical equipment attached to the fence.][ Ground fences on
each side of all gates, at each corner, at the closest approach to each
building located within 15 m 50 feet of the fence, and where the fence
alignment changes more than 15 degrees. Grounding locations can not
exceed 198 m 650 feet. Bond each gate panel with a flexible bond strap
to its gate post. Ground fences crossed by powerlines of 600 volts or
more at or near the point of crossing and at distances not exceeding 45
m 150 feet on each side of crossing. Provide ground conductor consisting
of No. 6 AWG solid copper wire. Provide copper-clad steel rod grounding
electrodes 19 mm 3/4 inch by 3.05 m 10 foot long. Drive electrodes into
the earth so that the top of the electrode is at least 152 mm 6 inches
below the grade.
Where driving is impracticable, bury electrodes a minimum of 305 mm 12
inches deep and radially from the fence, with top of the electrode not
less than 610 mm 2 feet or more than 2.4 m 8 feet from the fence. Clamp
ground conductor to the fence and electrodes with bronze grounding
clamps to create electrical continuity between fence posts, fence
fabric, and ground rods. Total resistance of the fence to ground cannot
exceed 25 ohms