PARLCARD306

N = Power delivered by the UPS (e.g. 20KVA). +1 refers to an extra power and battery module for redundancy. If there is a fault in one module it can be replaced while still providing fully protected power.

N+N is a second complete UPS wired in parallel, distributing 50% of the load evenly across the two units. If one UPS were to fail, the load would be seamlessly picked up by the reciprocal UPS.

Redundant redundancy, for the most critical applications. Two N+1 UPS systems in parallel to increase reliability exponentially and eliminate downtime. Provide confidence that you are prepared for the unexpected.

If N+1 is purchased, YES! If your system is not configured for N+1, each power module supplies 10KVA of power, so if you are running 20KVA of load on a 40KVA system you can swap power modules because the system will remain running on 30 of 40KVA, easily picking up your 20KVA load until the new power module is installed. For batteries, the same applies. If at least one extra battery string is provided, the UPS can operate fully protected while the battery modules are replaced one at a time.

If the power feed is protected upstream, by an appropriately sized overcurrent protection device, an input circuit breaker is not required. If the output is feeding a distribution panel with a properly sized main circuit breaker, the output breaker is not required. With all of that said, having the circuit breakers located at the UPS adds an extra disconnect point, centralized at the UPS for quick and easy bypass function for repairs or maintenance. If paralleling UPS systems, both systems should be equipped with the optional circuit breakers.