Tuesday, 1/26 (Part 2)
Upon completion of the excavation, Brian went back to project grounding rod. Thankfully, the materials needed were in stock locally so he was able to start working on it immediately. Additionally, our electrician friend lent us his Bosch SDS rotary hammer and two different sledge hammers.
The grounding rods are 5/8″ wide and 8 feet long. In New Mexico, they must be hammered into a 30″ deep trench, so Brian had to drive them in about 6 feet to put their tops 6″ underground. The copper wire that will connect them is 2 gauge bare copper. As you are likely aware, we are dealing with some HARD soil so this was not the world’s quickest task. Additionally, the rods are thin and springy and with each hit, they may or may not whip back and forth like a big antenna. The T-post hammer was good for getting started, but for finishing the job, the best tool ended up being the flat side of a 24 oz ball-peen hammer.
Note that Brian was unable to get the Bosch SDS going because he hadn’t fully allowed quick release chuck to re-engage and the tool won’t operate with it half engaged because it might launch the bit like a missile.
Brian took some time in the morning to review the electrical code with regards to grounding rod depth under soil. He also connected with the electrical inspector and scheduled the ‘underground inspection’ for that very afternoon. What a lovely turnaround.
We had underestimated the wire needed for the grounding operation, so after a quick trip to the electric supply depot, Brian got to it. The wire was clamped in place. To anyone doing this: put the acorn clamps on the grounding rods before they mushroom (Brian did this) and thread the bare copper wire through the clamp closer to the breaker panel first (Brian didn’t do this). It ends up being kind of a wire-bendy hassle to thread the far clamp first because 2 AWG copper is so stiff.
The local inspector arrived on the scene around 3:45pm and gave us the green light. He also told Brian he needed to clamp the mast higher than we had thought. To do this, Brian will have to ‘build out’ a bracket with lego-like strut products. Should be interesting.
Before calling it a day, Brian started to dig out the connection from the grounding trench to the electric box. It basically needs to be 24″ deep and is probably a 6′ stretch of dirt. That’ll put the wire (encased in a PVC conduit) directly underneath the electric box.
Planned out the bonding to ground all the structural metal parts and incorporate the extra 2 gauge wire from the grounding project. Purchased bonding parts. Drilled holes in foundation beams for the bonding.
We examined the bonding options – run bonding wires directly into a clamp on the near ground rod or up through the wall into the panel. This decision needed to be made prior to filling in the trench. We ultimately decided to run the wires in the wall, which will keep things hidden and tidy looking from the outside.
Lastly, Brian worked more on digging out the connection trench. He hit some cement-slab-like pieces of compacted dirt that did not want to crumble. Again, not the fastest task.