What must all equipment intended for use in photovoltaic systems have applied to them?

In photovoltaic systems as governed by the National Electrical Code (NEC), it is essential that all equipment used within these systems bears a field label. This field label is a crucial marker that signifies compliance with specific safety and performance standards. Such labeling ensures that the equipment has been inspected and meets the appropriate codes and regulations for installation and operation.

The field label is particularly important for equipment used in systems that involve varying degrees of exposure to outdoor conditions and electrical loads, as it helps to inform installers, inspectors, and users that the equipment has been deemed acceptable for use in the field. This requirement promotes safety and functionality, minimizing risks associated with improper installation or the use of inadequate equipment.

Conversely, while a warranty label provides information regarding the manufacturer's guarantee on the product, it does not necessarily indicate compliance with safety or performance standards. An operational guide is helpful for proper usage and maintenance but is not applicable as a certification for safety or compliance. A safety certification is often recognized as a broader statement about a product’s overall safety but does not specifically address the need for ongoing compliance during installation and operation in the field, which is what the field label ensures.