The service disconnecting means rated 1,000V or less shall be marked to identify it as being suitable for use as service equipment and shall be _____.

• A. listed
• B. field labeled
• C. listed or field labeled
• D. certified

Answer: (C)

In service equipment, the marking shows that the disconnecting means is suitable to be used as service equipment. The NEC allows this marking in two ways: the equipment can be listed by a recognized testing laboratory, or it can be field-labeled to indicate suitability for service use. This ensures the device has been evaluated for use as a service disconnect, including its electrical and safety characteristics for service conditions. A device that is merely listed is acceptable, and a device that is field-labeled is also acceptable, and some equipment may be both. The option “certified” isn’t the term used for this requirement. That combination—listed or field labeled—best covers the ways to show suitability for service equipment.