Code Change Summary: Changes were made to recognize aluminum and copper-clad aluminum conductor material for use as a bonding jumper.

The previous code language in 250.102(A) required bonding jumpers to be of copper “or other corrosion-resistant material”. This code language left wiggle room for those trying to determine if aluminum is considered corrosion-resistant.

For several code cycles now, there has been a movement throughout the NEC^® to recognize the performance of aluminum and copper-clad aluminum conductors and their resistance to corrosion.

Both copper and aluminum is susceptible to corrosion and there are many misconceptions regarding the corrosion resistance of each material. Between copper and aluminum, copper is the most cathodic, or noble, and the effects of galvanic reaction is typically less in copper over aluminum. As a result, the general opinion of the electrical industry is that copper is corrosion resistant in almost any environment and aluminum is regarded as non-corrosion-resistant. However, placing copper in contact with more noble metals such as nickel or titanium would result in the copper corroding just as readily as aluminum. Installation conditions and other environmental factors play a big role in corrosion and the push from the aluminum industry to recognize its resistance to corrosion is evident in several code sections.

In the 2017 NEC^®, this code section changed to make it clear that bonding jumpers shall be of copper, aluminum, copper-clad aluminum, or other corrosion-resistant material.

Below is a preview of Article 250. See the actual NEC^® text at NFPA.ORG for the complete code section. Once there, click on their link to free access to the 2017 NEC^® edition of NFPA 70.