For overseas buyers targeting North America’s $54 billion light box market, the UL certification of double-sided circular light boxes is no longer just a "market access pass"—it has become a core competitive advantage in commercial scenarios such as retail storefronts, gas stations, and urban advertising. In 2024, UL (Underwriters Laboratories) launched key updates to standards including UL 48 (Electric Signs) and UL 1598 (Lighting Equipment), which directly affect the compliance of circular light boxes in North American commercial applications. This article deciphers the updated requirements and provides practical compliance guidance for global buyers.

UL certification is recognized by U.S. federal regulations and Canadian provincial standards, covering electrical safety, mechanical stability, and environmental adaptability—three pain points for commercial light box applications. For double-sided circular light boxes, which feature a curved structure, dual-sided lighting design, and frequent outdoor use, UL certification solves three core concerns of North American buyers:

• Safety Compliance: Avoid customs detention and fines (up to $10,000 per shipment) for non-compliant products, and prevent lawsuits caused by electrical failures such as short circuits.
• Market Trust: Retailers like Walmart and CVS require suppliers to provide UL certification documents, and certified products have a 30% higher consumer acceptance rate in commercial bidding.
• Durability Guarantee: UL’s strict environmental tests ensure light boxes can withstand North America’s extreme climates, from Alaska’s -40℃ cold to Florida’s hurricane rains.

A 2025 survey by the American Signage Foundation shows that 82% of commercial light box procurement projects in North America list UL certification as a mandatory requirement, an increase of 15 percentage points from 2023.

The 2024 revisions to UL 48 and UL 1598 (Rev. January 31, 2024) have added targeted requirements for double-sided circular light boxes, focusing on three key areas:

The updated UL 48 standard emphasizes two mandatory requirements for LED double-sided light boxes:

• LED Driver Harmonic Current Limit: New limits on harmonic currents generated by LED drivers have been added, requiring compliance with IEEE Std 1789-2015 to avoid interfering with the North American power grid. This means that low-quality non-certified drivers previously used by some manufacturers will no longer pass testing.
• Secondary Circuit Grounding: UL 1598 now mandates independent grounding for the secondary circuits of double-sided light boxes (the circuit part directly connected to the LED panel), which reduces the risk of electric shock caused by insulation failure by 60% compared to the old standard.

For example, a 120V commercial circular light box must now pass a 1500V withstand voltage test for its secondary circuit, with no breakdown allowed for 1 minute.

Aiming at the curved structure of circular light boxes, the updated standard has refined mechanical safety and material flame retardancy requirements:

• Curved Panel Impact Resistance: The acrylic or PC panel of the light box must pass a hail impact test—using a 25mm diameter ice ball to hit the panel at 20m/s without cracking or breaking, which is a key update for regions prone to hailstorms such as the U.S. Midwest.
• Flame Retardancy Upgrade: All plastic components (including frame and diffuser) must meet UL 94 V-0 flame retardant grade, an upgrade from the previous V-2 requirement. This prevents fire spread in commercial spaces such as shopping malls.

The updated standard has standardized the labeling requirements for double-sided circular light boxes, which must include:

1. UL certification mark and certification number (permanently affixed to the frame, not easy to wear);
2. LED light source lifespan (not less than 50,000 hours) and compatible driver parameters;
3. Warning labels for installation orientation (circular light boxes have strict front/back installation requirements to avoid light leakage);
4. FTC Lighting Facts energy efficiency label (synchronized with North American energy consumption regulations).

Buyers should note that missing any of the above labels may result in refusal of market access during retailer audits.

Different commercial application scenarios correspond to differentiated UL testing requirements. Kingwe-star summarizes three common scenarios and their core standards:

A Toronto-based advertising company planned to import 300 double-sided circular light boxes for a fast-food chain’s outdoor promotion in early 2024. Initially, the supplier provided products certified to the old UL 48 standard, which lacked secondary circuit grounding and new labeling. During the pre-shipment inspection, Kingwe-star’s compliance team identified the issue and proposed two solutions:

1. Upgrade the LED driver to a UL-certified model with harmonic current control, adding independent grounding wires;
2. Supplement the standardized labels and provide a third-party test report from a UL-accredited laboratory (TÜV SÜD).

After the rectification, the products passed Canadian customs clearance smoothly, and the fast-food chain’s promotion was launched on schedule. The buyer’s procurement manager stated: "The updated UL certification not only avoids fines but also makes our products more competitive in the local bidding."

Based on serving 87+ North American light box buyers, Kingwe-star summarizes a three-step compliance method:

1. Clarify Requirements in Advance: Provide the supplier with detailed application scenarios (e.g., "outdoor in Chicago" or "gas station in Texas") to confirm the applicable UL standards and test items.
2. Verify Core Components: Check whether key parts (LED driver, power cord, plastic shell) have independent UL certification. Using certified components can shorten the overall certification cycle by 40%.
3. Pre-Test to Avoid Risks: Conduct pre-testing of key items (such as withstand voltage and flame retardancy) before formal certification, which can reduce the rework cost caused by test failure by 50%.

To help overseas buyers quickly adapt to the 2024 UL certification updates, Kingwe-star provides free one-stop services: including UL standard interpretation, component selection guidance, and third-party test report review. Our team of engineers with 10+ years of experience in lighting certification can simulate North American commercial scenarios to conduct targeted pre-testing, ensuring that each batch of double-sided circular light boxes meets market requirements.

For a personalized UL certification compliance checklist for your commercial light box project, please contact Kingwe-star or visit Kingwe-star to submit your needs.