Which UPS system type is usually considered to have a lower number of single points of failure?

In the context of uninterruptible power supply (UPS) systems, the N+1 system is designed to enhance reliability by reducing the likelihood of single points of failure. An N+1 configuration means that for every critical component required to provide power, there is an additional component available as a backup.

This redundancy allows the system to continue functioning smoothly even if one component fails, as the extra component can take over the load. Therefore, in the event of a single point of failure (like the failure of a UPS unit), the system remains operational due to the presence of the extra unit.

In contrast, other configurations may not provide this level of backup. For instance, an N system has no redundancy, while a 1N system has just enough capacity to meet the base load without any extra components. A parallel redundant system can also enhance reliability but may not always be as structured in terms of redundancy planning as an N+1 system.

Thus, the choice indicating an N+1 system highlights its robust design that significantly reduces the chances of critical failures due to its inherent redundancy, making it the preferred choice when reliability is the primary concern.