What is in this article?:
- What's Wrong Here?
- Find the Answer
Hint: This 0.625-inch diameter, 8-foot ground rod electrode is connected to a water pipe clamp.
Find the Answer
Tony Scaffidi, technical support engineer, Pieper Electric, Milwaukee, submitted this response to the photo in the December issue. “All ground clamps and fittings shall be approved for general use without protection or be protected from physical damage [250.10(1) and (2)]. Where practicable, rods, pipe, or plate electrodes shall be embedded below permanent moisture levels and free of nonconductive coatings [250.53(A)]. The rod shall be driven so that 8 feet is in contact with the earth. Since there's only a couple of inches showing over the concrete, it doesn't look like they had any trouble driving the rod in [250.53(A) and (G)]. It's hard to tell from the picture what type of conductor is used, but 250.64(A) and (B) tells us that a grounding electrode conductor shall be securely fastened to the surface on which it is carried. A 4 AWG conductor, or larger, is required to be protected from physical damage if exposed.”
In addition to citing the same violations as Scaffidi, Marc Blaine, electrician, Colgate Palmolive Co., Morristown, N. J., noted: “Grounding conductors and bonding jumpers shall be connected by listed clamps or other listed means. The clamp used in this instance is a water pipe clamp, not a recognized ground rod clamp [250.8].” He added, “250.70 covers pretty much the same subject indicated in 250.8, but also notes ‘Ground clamps …, where used on pipe, rod, or other buried electrodes, shall also be listed for direct soil burial or concrete encasement.’ The plated steel screws used to make the conductor connection and maintain the grip of the two clamp halves on the electrode often rust through over time, creating a poor (high resistance) connection. A ground rod clamp (acorn) is made of non-corroding material, which is why it gets the UL Listing for this application and the water pipe clamp doesn't.”
Bob O'Brien, project manager, Riggs Distler & Co., Inc., Sharon Hill, Pa., also identified a combination of violations noted by the two other December winners.