Pier grounding detail
- Thread starter anbm
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petersonra
Senior Member
- Location
- Northern illinois
- Occupation
- engineer
perhaps the building steel is not a grounding electrode as defined by the code.
or maybe someone just decided to do it this way.
or maybe someone just decided to do it this way.
MRKN
Member
- Location
- California, USA
If the structure is electrically served, then it is required to be grounded.
If there is 20 linear feet or more of interconnected rebar, an astute inspector will require it to be connected to the proposed ground rod under 250.50. Which in turn obviates the need for the ground rod in the first place.
However something the code does not cover is longer term galvanic corrosion. I would recommend you to simply coil 20' of bare Cu #4 elevated off the lowest rebar with PVC spacers and be done with it.
If there is 20 linear feet or more of interconnected rebar, an astute inspector will require it to be connected to the proposed ground rod under 250.50. Which in turn obviates the need for the ground rod in the first place.
However something the code does not cover is longer term galvanic corrosion. I would recommend you to simply coil 20' of bare Cu #4 elevated off the lowest rebar with PVC spacers and be done with it.
gadfly56
Senior Member
- Location
- New Jersey
- Occupation
- Professional Engineer, Fire & Life Safety
I'm not sure if the detail intends this, but it appears that the ground rod is driven under the pier, with an exothermic welded wire. My understanding is that the pier should be poured on top of undisturbed or compacted ground, or gravel. That doesn't appear to be what they are doing here.
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