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UL 62368-1 Certification Guide — Test Requirements & Process
UL 62368-1 is the prevailing safety standard for audio/video, information, and communication technology equipment in the North American market. Built on the IEC 62368-1 framework, it adopts a Hazard-Based Safety Engineering (HBSE) methodology — a fundamentally different approach from the legacy standards it replaced. This guide covers the core test requirements, end-to-end certification process, and practical considerations that manufacturers commonly encounter. For tailored guidance, reach out to GTG Group.
What Is UL 62368-1?
UL 62368-1 is a safety standard published by UL (Underwriters Laboratories) that covers audio/video equipment, information technology devices, and communication technology products. It is based on the international standard IEC 62368-1 and has formally superseded two long-standing predecessors: UL 60065 (audio/video apparatus) and UL 60950-1 (information technology equipment).
A common misconception is that UL 62368 is simply a merger of the two older standards. In practice, the shift is more fundamental. Rather than prescribing test clauses by product category, UL 62368 employs a risk-based framework that starts with energy sources — electrical, thermal, mechanical, and others — and classifies them by hazard level. Products must then demonstrate appropriate safeguards at three tiers:
- Basic Safeguard — first line of defence under normal operating conditions
- Supplementary Safeguard — activated when the basic safeguard fails
- Reinforced Safeguard — a single measure that replaces the combination of basic and supplementary safeguards, used in higher-risk scenarios
This hazard-based approach means that two visually similar products may follow entirely different compliance paths depending on how their internal energy sources are distributed and managed.
Products Covered by UL 62368-1
UL 62368-1 applies to a broad range of consumer and professional electronics. The main product categories include:
- Audio equipment — power amplifiers, active speakers, headphones, mixing consoles, audio interfaces
- Video equipment — monitors, projectors, televisions, cameras, video capture devices
- IT equipment — desktops, laptops, servers, printers, scanners, network-attached storage
- Communication devices — routers, switches, modems, set-top boxes, VoIP phones
- Consumer electronics — gaming consoles, smart home hubs, wearable devices
- Power supplies and accessories — external adapters, chargers, UPS units
Certain product types — medical devices, industrial control systems, and luminaires, for example — may fall under separate or additional standards. It is worth confirming scope applicability before initiating a UL 62368 project to avoid scope-related delays down the line.
Core Test Requirements
The UL 62368 test programme is structured around three pillars: electrical safety, mechanical integrity, and fire enclosure performance. Each pillar addresses specific hazard types identified through the HBSE methodology.
Electrical Safety
- Insulation resistance — verifies that electrical isolation between circuits of different potentials is adequate under specified conditions
- Dielectric voltage withstand — applies a voltage above the rated level for a set duration to stress-test the insulation system
- Earth continuity — confirms a low-impedance ground path capable of carrying fault current safely
- Leakage current — measures touch-current levels to ensure they remain within the limits defined by the standard
- Temperature rise — monitors critical points (transformers, power semiconductors, enclosure surfaces) under rated load over an extended run period
Mechanical Safety
- Stability — evaluates tip-over risk during normal use and reasonably foreseeable misuse
- Enclosure strength — impact testing to verify the housing can withstand mechanical abuse without exposing hazardous parts
- Moving parts guarding — checks that fans, gears, and other rotating components have adequate protective barriers
Fire Enclosure
- Glow-wire test (GWT) — simulates overheating from poor contacts or overload conditions and assesses self-extinguishing behaviour
- Needle-flame test — applies a small flame source to replicate ignition from a failing internal component
- GWIT and GWFI ratings — quantifies glow-wire ignition temperature and flammability index for materials used in the product
Energy Source Classification
Class 1 Energy sources accessible under normal conditions; low hazard level — no additional safeguard typically required
Class 2 Limited energy sources; moderate hazard — basic safeguard is mandatory
Class 3 Hazardous energy sources; high hazard — reinforced safeguard required; contact may result in serious injury
In one recent project involving a batch of IT equipment, the power supply module reached a surface temperature of 78 °C after 4 hours of full-load operation — comfortably within the standard's limit. However, units with suboptimal thermal design pushed past 95 °C, putting them at risk of failing the temperature-rise test. The difference came down to PCB layout and heatsink design choices.
Certification Process — Step by Step
A typical UL 62368 certification project follows six stages. The overall timeline depends on product complexity, number of test cycles, and the completeness of submitted documentation.
- ①Scoping & Technical Review — The manufacturer submits product specifications, schematics, PCB layouts, and a critical component list. The certification body reviews these against the applicable clauses of UL 62368-1 and identifies potential technical hurdles early.
- ②Sample Preparation — Typically 2–3 fully functional production-representative samples are required, along with standalone samples of key components (power supply modules, transformers). Any deviation from mass-production design should be flagged upfront.
- ③Application Submission — The formal UL application is filed with company and product details. UL assigns a project number and a responsible engineer, officially kicking off the engagement.
- ④Product Testing — The laboratory evaluates the product against each applicable clause of UL 62368-1. If non-conformances are found, the engineer issues a report detailing the findings. The manufacturer then has a defined window to implement corrective actions and resubmit.
- ⑤Initial Production Inspection (IPI) — A UL field auditor visits the manufacturing facility to verify that production processes, quality-control systems, and critical component controls meet the certification requirements.
- ⑥Certification & Ongoing Surveillance — Once testing and the factory audit are cleared, UL issues the certification. The manufacturer is then subject to periodic Follow-Up Service (FUS) inspections to maintain the certificate's validity.
Practical tip：The biggest schedule risks rarely come from the testing itself. They come from incomplete samples, documentation mismatches, and unanticipated retest cycles. Running an internal pre-compliance check before formal submission can catch most of these issues early — consider engaging a specialist certification partner for a gap analysis at this stage.
Common Pitfalls and Practical Considerations
Critical component changes Replacing a safety-critical component (power module, transformer, optocoupler) on a certified product may trigger partial retesting or supplemental evaluation. Establish an internal change-control process and consult the certification body before making substitutions.
Marking and nameplate compliance Product nameplates must include the UL mark, model designation, and electrical ratings. The durability of these markings is verified through rub and scrape tests — non-compliant marking is a frequent cause of project delays.
Design change notification Circuit modifications, structural changes, and material substitutions must be reported to UL promptly. In a recent smart-speaker project, an unreported PCB layout revision led to a supplemental test requirement that added weeks to the schedule.
Documentation-to-sample consistency Schematics, BOMs, and specifications must match the actual samples submitted. Discrepancies — even minor ones like a capacitor's voltage rating differing between the drawing and the physical part — will halt testing until resolved.
Watch out：One of the most common reasons for test interruptions is a mismatch between submitted documentation and physical samples. For instance, a schematic may specify a 250 V-rated capacitor while the actual board uses a 200 V part. These details are cross-checked item by item during evaluation. A dedicated pre-submission review — comparing every component on the BOM against what is actually on the board — is time well spent.
Frequently Asked Questions
Q1 How does UL 62368-1 differ from the old UL 60950-1?
UL 60950-1 followed a prescriptive approach — specific test clauses mapped to specific product types. UL 62368-1 takes a fundamentally different route: it starts with energy sources, classifies their hazard levels, and then requires safeguards proportional to the risk. The two standards differ not only in test procedures but in the underlying logic that determines what gets tested and why.
Q2 What samples are needed for UL 62368 testing?
Generally 2–3 fully functional samples that represent the final production design. Key sub-assemblies (power supplies, transformers) may need to be submitted separately. If the product has multiple variants or configurations, discuss with the certification body upfront which models can be covered under a single report.
Q3 Do products already certified to UL 60950-1 need to be recertified?
UL 60950-1 and UL 60065 have been formally withdrawn. During the transition period, existing certificates remain valid — but any new application, certificate renewal, or significant design change will require compliance with UL 62368-1. Planning the standard transition early helps avoid last-minute disruptions to product launch timelines.
Q4 How much does UL 62368 certification cost?
Costs vary significantly based on product type, complexity, and the scope of testing required. The best approach is to provide detailed product documentation to a certification body for a tailored quotation.
This article was generated with AI assistance. Content is for reference only and does not constitute any certification commitment or legal advice. Refer to the latest official regulations for authoritative guidance.
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