Which label should service entrance terminals have when using aluminum wire or cable?

Service entrance terminals need to be clearly labeled to indicate the type of wire or cable being used for safety and compatibility purposes. The designation "Al-Cu" stands for aluminum to copper compatibility, which is crucial when connecting aluminum wires to terminals that may be made of copper or vice versa. This labeling ensures that the terminals can accommodate aluminum wires safely, minimizing the risk of overheating or connections degrading over time.

When aluminum wire is used, it is essential for service entrance terminals to recognize the distinct properties of aluminum compared to copper. Aluminum requires specific handling techniques and may expand or contract differently than copper, which can affect the connection if not specified correctly. Therefore, the "Al-Cu" label provides assurance that the terminals have been designed to handle aluminum wiring effectively.