Surge Protection Device Testing and Certification Services

UL Solutions provides investigations, testing and certification services for surge protective devices (SPDs), helping you demonstrate compliance and reach target markets efficiently. Our portfolio includes surge protection device testing supporting projects from basic designs to advanced monitored SPDs.  

What we cover in surge protection services 

We support the entire SPD industry, from light commercial and residential applications to complex devices that monitor surges and indicate SPD status, with a flexible service approach tuned to your product and markets.  

From concept through installation 

Our approach helps align compliance testing and certification so teams can focus on performance and safety while preparing for real‑world installation and end‑use considerations.  

SPDs help protect equipment from surges and spikes, including those caused directly or indirectly by lightning. They can be standalone devices or components within equipment installed on AC or DC power systems.  

Use cases across AC and DC power systems 

SPD applications vary by the surge withstand capability of the equipment, protection level desired, site geography and the equipment’s criticality. This is why SPD strategies differ across building systems and operating environments.  

Code‑driven applications 

Use of SPDs can be mandated by codes or local requirements. Examples include NEC^® (NFPA 70) Article 285 for installation and lightning protection standards such as UL 96A Installation Requirements for Lightning Protection Systems and NFPA 780 where surge protection is an integral system element.  

Related resource for code context: Learn how the 2024 IBC references UL 96A or NFPA 780 for LPS and calls for surge protection on power and communications systems. Read the update. 

Our comprehensive services can help you streamline market access while reducing time and cost through a well-proven global certification program.  

One certification process, multiple markets 

With combined testing for SPDs, UL Solutions can help you obtain the UL Mark for North America along with other certifications or schemes for international markets, one certification process designed for faster speed to market.

Tools to specify and verify SPDs 

Use iQ for Surge Protective Devices to find, verify and specify UL‑certified SPDs across more than 20 search parameters; the database houses 100,000+ UL Listed products and Recognized Components and is updated daily. Explore the database. 

Our areas of expertise cover SPD device families and component technologies used across commercial and industrial applications.  

Device‑level SPDs (Types 1–3) 

We test permanently connected SPDs (Types 1, 2, 3), cord‑connected and direct plug‑in (Type 3), receptacle type (Type 3), open‑type (Types 1–3), molded case SPDs (Types 1–2), and SPDs certified for use in specified equipment (Types 1–2).  

PV and DC SPDs (Types 1–4 component assemblies; Type 5 components) 

We also evaluate photovoltaic (PV) SPDs (Types 1, 2 and Type 4 component assembly, Type 5 component) and DC SPDs (Types 1, 2, 3 and Type 4 component assembly, Type 5 component). Modular component SPDs across these types are included.  

Component technologies (MOVs, GDTs, SADs, hybrids) 

UL’s scope includes discrete component SPDs such as metal oxide varistors (MOVs), gas discharge tubes (GDTs), silicon avalanche diodes (SADs/ABDs) and hybrid combinations.  

Our laboratories have invested in surge testing equipment that helps streamline evaluations and offer flexible testing options to decrease time to market. We perform surge testing to global SPD standards for AC, DC and PV applications.

Surge testing capabilities 

UL facilities in North America and Taiwan employ impulse current generators to perform surge testing aligned to applicable standards, supporting a broad range of SPD designs and ratings.

Related protection and safety services 

For adjacent commercial power protection needs, such as protective switching devices (e.g., relays, emergency stop, disconnects), UL Solutions provides testing and certification to help streamline global access. See Electrical Protection Devices Testing and Certification. For broader testing and certification offerings across markets and technologies, explore UL Solutions services pages. Testing • Certification 

Lightning & code pathways 

If your project includes a lightning protection system, see UL Solutions installer and inspection programs (including Master Label^® Certificate inspections) and how codes reference surge protection in LPS contexts. Lightning Protection Installer and Master Label Certificate Program • IBC 2024 update