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UPS Runtime for Office Equipment
Branch office UPS planning covers multiple desks, networking, and sometimes phone systems—but rarely high-inrush copiers on the same protected feed.
Who this scenario is for
Best for: Facility leads sizing a 5 kVA class UPS for desktops, switches, and VoIP on one branch.
Not ideal for: Open-plan floors with centralized motor loads, or sites where code requires stamped backup studies only.
Quick answer
Aggregate steady office watts—often near 1.5 kW on a 5 kVA UPS with 48 V / 100 Ah—for screening near 45–75 minutes before derates; exclude laser printers from the protected bus.
Key variables
- Diversity across desks: Not every workstation peaks simultaneously—document whether you use connected or diversified kW.
- Excluded high-inrush loads: Laser printers and copiers usually belong on utility-only circuits to avoid UPS overload trips.
- Growth and refresh cycles: IT refreshes add watts—carry margin in load estimates before locking battery Ah.
Example: office cluster on 5 kVA
1.5 kW steady, PF 0.85, 48 V / 100 Ah on a 5 kVA frame screens under an hour for graceful shutdown if batteries are healthy—re-run after adding desks or PoE switches.
Next steps — tools
- UPS Runtime Calculator — minutes at your kW, V, and Ah.
- UPS Load Calculator — roll up devices before runtime.
- UPS Battery Calculator — Ah for a target minute goal.
- UPS Capacity Calculator — required kVA with PF and margin.
Assumptions and disclaimer
Figures on this page are planning estimates using typical efficiency (~0.8) and safety factor (~0.7). Battery age, temperature, discharge rate, and UPS topology change real minutes. Confirm procurement with manufacturer runtime charts and your licensed engineer where required.
Frequently asked questions
Can a laser printer share the office UPS?
Generally no—inrush can overload the inverter. Keep printers on utility power.
How do I roll up watts for several desks?
Use the UPS load calculator with device counts, or sum measured plug-meter readings.
When is 5 kVA enough for an office branch?
When diversified kW and PF still fit utilization targets—pair capacity sizing with runtime minutes here.
Related UPS scenarios
Main UPS Runtime Calculator · How to calculate UPS runtime (guide)