Load Bank Utilization in Data Centers

A Technical White Paper from ASCO Power Technologies

In the data center industry, power reliability is paramount. A facility with 99% uptime—which sounds impressive—still experiences nearly 88 hours of downtime per year. For larger data centers, where a single minute of downtime can cost an average of $7,900 USD, ensuring every electrical component operates flawlessly is not just an engineering goal; it is a business necessity.

A key tool in achieving this reliability is the load bank. ASCO Power Technologies’ white paper, "Load Bank Utilization in Data Centers," provides a comprehensive guide on how and where to use load banks to validate and maintain critical power systems. This article summarizes the key applications and benefits outlined in the paper.

Why Use Load Banks in Data Centers?

Load banks are devices that simulate real electrical loads to test and stress power sources and distribution systems. They are the only practical way to create a "real-life" power demand during the commissioning and testing phases of a data center’s life, especially before actual server racks are installed.

The white paper identifies four main applications for load banks in a data center’s lifecycle:

1. Commissioning: Testing all new systems and components to ensure they are installed, operate safely, and meet performance requirements before the data center goes "live."
2. Maintenance & Periodic Testing: Rigorously testing back-up power supplies (like generators and UPS systems) to identify potential issues and ensure reliability.
3. Expansion: Simulating the increased power and cooling load of new equipment, validating that the expanded infrastructure can handle the demand.
4. Component Replacements: Testing new components (e.g., a replacement generator) to ensure they perform correctly and are compatible with the existing system.

Where Are Load Banks Used?

The paper provides a clear guide on where load banks should be utilized in a data center and the typical types used for each application.

• Back-up Diesel Generators: Simulate electrical load to test the engine’s capability, prevent "wet stacking" (a condition caused by running under no or light load), and ensure full power output. Typical load bank type: Resistive & Inductive (to fully test the kVA rating); often permanent for larger sites.
• UPS Systems: Discharge batteries to maintain health, determine battery autonomy (run time), and test inverters and distribution under load. Typical load bank type: Resistive; often permanent.
• HVAC Systems: Use the heat produced by the load bank to simulate server heat output, testing the cooling system’s effectiveness and validating hot/cold aisle designs. Typical load bank type: Resistive; portable or networked.
• Substation: Test gross capacity and verify the correct operation of relays, metering, and protection systems. Typical load bank type: High-voltage (HV); often permanent.
• PDUs & RPPs: Verify correct power distribution and monitoring from the PDU to the remote power panels and ultimately to the server racks. Typical load bank type: Resistive; portable.
• Bus Tracks: Test the power units, feed tracks, and tap-offs for efficient power distribution to the racks. Typical load bank type: Resistive; portable.
• Server Racks: Simulate the heat and power consumption of servers to validate cooling designs and power delivery before expensive servers are installed. Typical load bank type: Rack-mounted; portable.

Detailed Application Overview

1. Commissioning: Validating Before Going Live

Commissioning is the critical phase where potential issues are identified and corrected before they can cause downtime. Load banks are essential because real servers are not typically available during early construction. They provide the only practical way to test the entire electrical chain, from the utility or generator down to the rack-level power distribution.

2. Maintenance & Periodic Testing: Preventing Failure

Data centers typically rely on back-up UPS systems and diesel generators. Regular load bank testing is vital to maintain these assets. Tests can be performed automatically to build a historical record of the generator’s health, identifying any degradation in performance over time and allowing for preventative maintenance.

3. Networked Testing for HVAC Validation

Modern load banks can be connected in a network and strategically placed throughout a data center hall. This allows operators to simulate heat output from actual server locations, creating realistic "hot spots" and testing the cooling system’s response. This approach can validate hot/cold aisle cooling designs before servers are installed, avoiding costly rework later.

4. Rack-Mounted Load Banks for Aisle Design

Smaller, purpose-built load banks can be mounted into standard server racks. They precisely simulate the electrical load, airflow, and heat profile of production servers. This allows data center managers to validate the cooling design and the power delivery to each rack before commissioning begins, reducing the risk of costly downtime and reconfiguration later.

Renting vs. Purchasing Load Banks

The white paper notes that the decision to rent or purchase load banks depends on several factors specific to the data center:

• Location: Is equipment readily available locally?
• Size: How much load needs to be tested?
• Security: Does the site have strict access policies for outside equipment?
• Maintenance Schedule: Is testing required frequently (favoring purchase) or only for initial commissioning (favoring rental)?

Conclusion

For modern data centers, where uptime is critical, load banks are an indispensable tool. They provide the only reliable method to test and validate the entire electrical infrastructure—from generators and UPS systems to the server racks themselves. By using load banks during commissioning, maintenance, expansion, and component replacement, facility operators can ensure a reliable power supply, prevent costly downtime, and protect their business reputation.

Download the Full White Paper

This overview is based on the white paper "Load Bank Utilization in Data Centers" from ASCO Power Technologies. The full document provides further detail on load bank types and best practices.

The paper is available to download for free directly from ASCO Power Technologies:

Download the White Paper (PDF)

Note: This article provides a summary of a third-party white paper. While efforts have been made to accurately represent the content, please refer to the official ASCO document for complete technical details. Final design and testing decisions should be made by qualified professionals.