UL 1778, the Standard for Uninterruptible Power Systems
We provide testing and certification services for Uninterruptible Power Supply (UPS) Systems in accordance with UL 1778, the Standard for Uninterruptible Power Systems, along with other applicable safety Standards. Through our evaluation process, we assess the safety of your systems.
What is a UPS?
An Uninterruptible Power Supply is an electrical device designed to provide emergency power to a load when the main power source fails. A UPS offers near-instantaneous protection from power interruptions. There are UPS systems for industrial and consumer use cases. The UPS may safely shut down non-essential loads while continuing to provide power to critical equipment loads.
UPS systems have been providing this support for various applications for decades. A UPS utilizes stored energy from an integrated or external energy source, typically a battery bank, supercapacitor or the mechanical movement of a flywheel.
UPS vs. ESS
While UPSs and Energy Storage Systems (ESSs) may appear similar, they serve distinctly different purposes and operate in fundamentally different ways. A UPS shares some structural similarities with an ESS, such as the use of batteries, inverters and control electronics. However, the key differences lie in their intended function and operational behavior.
UPS functionality
A UPS is designed primarily to provide short-term backup power during outages, supporting the uninterrupted operation of critical equipment. Unlike ESS, which may operate in parallel with the grid and undergo frequent charge and discharge cycles, a UPS typically remains idle until a power disruption occurs. While some ESS configurations can offer UPS-like functionality, their primary role is broader — supporting grid interaction, energy optimization and load management — functions that go beyond the core purpose of a UPS.
Consumer applications of UPS equipment
- Home network equipment
- Gaming consoles
- Smart home hubs
Industrial applications of UPS equipment
- Data centers
- Server rooms
- Healthcare
- Telecommunications
- Financial institutions
Read our white paper to learn more about the current state of North American codes and standards for UPS products and evolving ESS.
Code compliance overview
We help your UPS equipment meet key regulatory requirements, including:
National Electrical Code® (NEC)
Section 645.11, 700.12(E), 701.12(E) and 708.20(G)
These sections outline specific requirements for installing uninterruptible power supplies (UPS) used in:
- Information technology systems
- Emergency systems
- Legally required standby systems
- Critical operation power systems
Section 110.3(B)
Requires that listed equipment be installed and used according to the instructions provided in its listing or labeling.
International Fire Code (IFC) and International Building Code (IBC)
IFC Sections 1203.1.3, 1203.4, 1203.5 and IBC Section 2702.1.3
These codes state that UPS systems used for emergency or standby power must be:
- Installed
- Inspected
- Tested
- Maintained
- In accordance with NEC, NFPA 110 and NFPA 111
National Fire Protection Association (NFPA)
NFPA 1 and NFPA 5000
Require that stored electrical emergency and legally required standby power systems comply with NEC and NFPA 111 for installation and maintenance.
Other relevant standards to which we can provide testing
- C22.2 No. 107.3, the Standard for Uninterruptible Power Systems (Canada)
- IEC 62040-1, Uninterruptible power systems (UPS) – Part 1: Safety requirements
- IEC 62477-1, Safety requirements for power electronic converter systems and equipment – Part 1: General
- UL 62368-1, the Standard Test Method for Evaluating Thermal Runaway Fire Propagation in Battery Energy Storage Systems
Where can we perform testing?
UL Solutions offers global testing capabilities for UL 1778 Uninterruptible Power Supply (UPS) Equipment, and other International Standards such as IEC 62040-1 Uninterruptible power systems (UPS) – Part 1: Safety requirements, with full-service laboratories strategically located to support manufacturers across key regions.
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Contact us today to learn how testing and certification for UPS systems can support your path to compliance.
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