Which two power sources are considered Source 1 on a CDB ATC?

In the context of a Central Distribution Board (CDB) Automatic Transfer Control (ATC), Source 1 typically refers to the primary or main power source that is used for normal operations. This source provides the necessary reliability and capacity to meet the demands of the system under standard conditions.

Choosing utility power as one of the sources is logical, as it is the standard form of power supply for many electrical systems and provides a constant and reliable source to support regular operational loads. Additionally, generator power serves as a suitable backup that can take over when utility power is unavailable or if there are issues with the primary supply. This combination ensures that there is always power available for essential systems, meeting the critical requirement of redundancy and reliability in power distribution.

The other choices involve sources that may not fulfill the necessary prerequisites for being classified as Source 1 due to factors like inconsistent generation or lower reliability compared to utility and generator power. For example, solar panels may not consistently produce power based on weather conditions, while backup generators often serve more as a secondary option rather than a standard source of power.