Which of the following is NOT a type of equipment mentioned that requires field marking?

The reason residential circuit breakers are not typically noted as requiring field marking is due to their installation context and scale. Residential circuit breakers are usually installed in home environments and are more straightforward in terms of their function and identification. In contrast, switchboards, panelboards, and industrial motor control panels are larger and often part of more complex electrical distribution systems, necessitating clear identification for safety, maintenance, and operational purposes. Field marking in these contexts serves to ensure that anyone interacting with the equipment can quickly understand its layout and functions, thereby enhancing safety and efficiency.

In complex installations, clear markings help prevent confusion, particularly in environments where multiple circuits or large electrical systems are present. This makes marking essential for equipment like switchboards and industrial control panels, where incorrect handling can have significant repercussions.