UPS & batteries

Backup power is sized by the load it must carry and the time it must hold. Online UPS units suit servers and sensitive equipment, while offline units suit basic desktop backup. State the VA or kVA rating, input and output phase, and required backup duration. For batteries, give the voltage, ampere-hour capacity and type, tubular, flat plate or sealed; chargers need matching voltage and current. Sizing should be checked by a qualified electrician.