Code Change Summary: Small editorial changes but a good clarification was made from CMP-1 in response to a Public Input that was denied.
The words “where” in Section 110.5 were replaced with the words “if” to bring this code section into compliance with the NEC® Style Manual. "If" is to be used to indicate a condition and "where" a location.
This was simply an editorial change, and the language in Section 110.5 still requires that if the conductor material is not specified, the sizes given in the Code shall apply to copper conductors, but something else occurred that provides some clarity on a different issue.
During the first draft stage of the 2023 NEC® development process, a public input was made to add the following statement to Section 110.5:
“Aluminum Conductors shall have anti-oxidant compound applied to termination points.”
The submitters substantiation was “The use of Ani-oxidant on aluminum conductors is not a requirement by the NEC® and should be.”
The code making panel resolved (denied) the Public Input and stated, “Aluminum conductors do not always require use of an anti-oxidant at terminations.”
This is a very common misconception that has infiltrated the minds of many electricians, electrical inspectors, and home inspectors.
Countless inspections are failed every year when inspectors see no evidence of antioxidant paste at aluminum wire terminations to a circuit breaker. When cross examined by the installer, the inspector will ask for proof that antioxidant paste is not required. Instead of doing the research, the installer usually adds antioxidant paste to each termination just to get the inspector to pass the inspection.
Oxide inhibitor creates a barrier at the termination or splice point that works to keep out moisture and other substances that may damage the connection. Some compression connectors come pre-filled with an oxide inhibitor.
According to the UL Guide Information on product category ZMVV which applies to Wire Connectors and Soldering Lugs, “some wire connectors supply instructions for the preliminary preparation of conductors, such as use of conductor termination compound (antioxidant compound)”. “Some connectors are shipped pre-filled with conductor termination compound (antioxidant compound). For non-prefilled connectors, conductor termination compound may be used if recommended by the connector manufacturer as preliminary preparation of the conductor”.
Some manufacturers require antioxidant paste at aluminum wire terminations or splices while others do not. The action and statement made by this code panel should hopefully put this misconception to rest.
Below is a preview of the NEC®. See the actual NEC® text at NFPA.ORG for the complete code section. Once there, click on their link to free access to the 2023 NEC® edition of NFPA 70.
2020 Code Language:
110.5 Conductors. Conductors used to carry current shall be of copper, aluminum, or copper-clad aluminum unless otherwise provided in this Code. Where the conductor material is not specified, the sizes given in this Code shall apply to copper conductors. Where other materials are used, the size shall be changed accordingly.
2023 Code Language:
110.5 Conductors. Conductors used to carry current shall be of copper, aluminum, or copper-clad aluminum unless otherwise provided in this Code. If the conductor material is not specified, the sizes given in this Code shall apply to copper conductors. If other materials are used, the size shall be changed accordingly.
Which of the following is required in Section 110.5?
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