Choosing the Right UPS: Why Selection Matters

UPS selection is a critical decision for any organization tasked with protecting sensitive equipment, data, and operations. Whether you're building a new facility or upgrading an existing power infrastructure, the uninterruptible power supply you choose must be aligned with your application’s power profile, load type, battery runtime expectations, and redundancy requirements. The wrong system (whether underpowered or overbuilt) can lead to inefficiencies, unnecessary costs, or worse, failures during outages.

This guide offers a structured, expert-led approach to selecting UPS systems, helping you match capacities and configurations to real-world conditions. It draws on best practices, practical design considerations, and highlights the modular capabilities within Legrand’s diverse UPS product range to support better decision-making.

Core Considerations for Effective UPS Selection

1. Define the Protected Equipment and Load Profile

UPS selection begins with a clear understanding of what you're protecting. Start by cataloging all connected devices, including:

• Servers and storage arrays
• Networking devices (routers, switches, firewalls)
• Building control systems
• Industrial controllers or medical devices
• Business-critical computers and workstations

For each device, determine the VA or watt rating, startup current, and whether it requires continuous backup or orderly shutdown.

Best practice: Include only critical equipment in your UPS load calculation. Non-essential devices (e.g., monitors, printers) may be better served by surge protection or alternate backup paths.

2. Determine Runtime Requirements and Battery Strategy

The amount of battery backup time needed varies by application. For many IT loads, 5 to 15 minutes of runtime is sufficient to bridge short outages or allow controlled shutdown. For healthcare, manufacturing, or edge data applications, 30 minutes to several hours may be required.

Considerations include:

• Do your devices require zero interruption, or is graceful shutdown acceptable?
• How long does the generator or alternate supply take to activate (if applicable)?
• Will you need external battery cabinets or extended runtime modules?

Legrand systems like the Trimod HE and Daker DK Plus offer scalable battery configurations and flexible runtime profiles tailored to both short-ride-through and long-duration backup requirements.

3. Select the Appropriate UPS Topology

Not all UPS systems are designed alike. Selecting the right topology depends on your application’s criticality and power environment.

For most business-critical environments, online UPS systems are the base standard. They ensure consistent power delivery, filter voltage sags or surges, and support sensitive equipment without interruption.

4. Factor in System Scalability and Redundancy

UPS selection isn't just about current needs, it’s also about planning for growth. Choose a system that supports modular expansion, allowing you to scale as your equipment base or backup duration increases.

Legrand’s KEOR MOD and Trimod HE platforms are designed for scalable deployment, supporting capacities from 25 to 250 kVA in modular blocks. These systems also support N+1 and 2N redundancy, ensuring backup capacity even during maintenance or internal failures.

Real-world tip: Redundant systems help meet uptime SLAs and regulatory requirements, especially in data centers, finance, healthcare and industrial automation sectors.

5. Evaluate Power Quality and Environmental Conditions

The environment in which your UPS operates will influence your system selection. Consider:

• Input power quality: Are there frequent surges, harmonics, or voltage fluctuations? Online systems are better suited for unstable supplies.
• Temperature and airflow: Batteries degrade faster in poorly ventilated or hot areas.
• Space constraints: Rack-mounted systems (like Legrand’s Daker DK) offer compact protection for tight IT spaces.
• Installation location: Edge sites and distributed branches may require smaller form factors with high resilience.

UPS systems are not just about backup—they also serve as power conditioning devices, protecting equipment from silent failures and long-term wear caused by poor-quality input.

Common Mistakes in UPS Selection and How to Avoid Them

• Underestimating runtime needs: Always match battery capacity to realistic outage scenarios, not theoretical minimums.
• Sizing for watts, not VA: UPS capacities are expressed in VA/kVA. Ensure you account for the power factor.
• Failing to account for inrush currents: Equipment like servers or motor-based devices may require higher capacity at startup.
• Ignoring system monitoring: Choose systems that integrate with SNMP or building control for proactive alerts.
• Selecting a fixed system in a growing environment: Opt for modular UPS platforms that allow additional capacity to be added as the application evolves.

Legrand Solutions for Precise UPS Selection

Legrand’s UPS portfolio is engineered to support a broad range of applications and sizing strategies:

• KEOR MOD
  Modular three-phase UPS system, scalable from 25 to 250 kVA. Designed for large IT, colocation, and industrial environments.
• Trimod HE
  Hot-swappable transformerless UPS ideal for enterprise IT and healthcare applications, available in 5–80 kVA capacities.
• Daker DK Plus
  Compact, line-interactive and online UPS models designed for desktop and rack-mount installations, from 1 to 10 kVA.

Each system is designed with modularity, battery flexibility, and real-time monitoring in mind. Ensuring your backup infrastructure evolves alongside your critical systems.

A Strategic Approach to UPS Selection

UPS selection is not a one-size-fits-all exercise. It requires a clear understanding of your protected equipment, application requirements, growth projections, and battery expectations. The right system should not only meet your current load but support future scalability and provide confidence during critical events.

Legrand’s uninterruptible power systems are built for precision, reliability, and ease of integration. Whether you’re protecting a small branch office, building-wide control systems, or enterprise-scale data infrastructure, our UPS products provide the capacity, protection, and flexibility to meet your goals.

To get expert guidance on selecting the right UPS for your application, connect with a Legrand specialist.