National Electrical Installation Standards

Standards as High as Your Own

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Wednesday, September 11, 2019

Question:

I work at a facility that has miles of chain link fencing, and that fencing has ground rods with a GEC every 50'. Whenever new fencing is built we do the same thing. When I ask why are we grounding fencing that is already 2' in the ground the answer is always, "this is how we've always done it'. Do you have any insight or history on why fence grounding is necessary. Thanks for all your help.  

Chloe R.
A

Answer:

Hey Chloe thanks for your question. You don't mention what voltage is used to supply the facility, or if it a special type of facility, but there are some specific rules about fence grounding in Article 250, Part X, for systems and circuits over 1000 volts. Examples include 250.190(A) and 250.194. Informational Notes in 250.191 and 250.194(A) reference IEEE 80, Guide for Safety in AC Substation Grounding for additional information about substations. For other applications the NEC does not require metal fences to be connected to grounding electrodes. If you are using fence contractors for the installations, ask them if anyone else is requiring the same thing. Maybe you asking the question can lead to save additional cost for future installations if there is no need for the additional grounding electrodes.

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