What is emphasized regarding conductor ratings in Article 690?

In Article 690 of the National Electrical Code (NEC), it is emphasized that conductors must be rated for the maximum system voltage or higher. This requirement is crucial for ensuring the safety and reliability of solar photovoltaic (PV) systems. Conductors need to be able to handle the maximum voltage that may be present in the system to prevent insulation breakdown, which could lead to short circuits or fires.

When conductors are rated appropriately for the maximum system voltage, they can operate safely under normal conditions as well as during events such as voltage spikes. By adhering to this specification, it helps to protect both the equipment and personnel from electrical hazards.

The other options do not align with the key principles outlined in Article 690. For example, while it is important for conductors to be rated for their operating current, this is not the primary emphasis in terms of voltage ratings, which is the focus of the correct answer. Similarly, the concept of under-rating conductors is not acceptable in the context of safety and code compliance. Lastly, while conductors must have specific voltage ratings, stating that they do not require them contradicts the fundamental safety objectives of the NEC.