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Wednesday, November 9, 2016
Question:
Looking at UL product specifications and specific manufactures listings it appears that a ground rod clamp, sometimes called an “acorn” clamp in the field, can be used to attach a copper grounding electrode conductor to a conductive iron rebar as part of the concrete grounding electrode system. If listed, this connection can be buried in concrete. A typical ground rod clamp would provide a pressure connection between the clamp and the iron bar. With the copper conductor in direct contact with the iron rebar, would this installation be considered a violation of 110.14 where dissimilar metals are in contact with one another?
Gary Beckstrand
A
Answer:
Hey Gary thanks for your question. Contact of dissimilar metals in terminal and splicing connectors is not permitted - unless the device is identified for the purpose and conditions of use as stated in the first paragraph of 110.14. Specific rules for the connections to grounding electrodes, including some listing requirements, are in 250.70. Manufactures typically provide the type and material a product is suitable for either on the product or packaging.