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LED lighting in the United States is governed by several different layers of requirements. Electrical safety, product listing, energy codes, lighting controls, flicker performance, and application-specific guidance can all affect whether a system is appropriate for a particular project.

These requirements do not come from a single “LED code.” They come from different sources, including the National Electrical Code, locally adopted energy codes, California Title 24 and JA8 requirements, product safety standards, and lighting performance guidance from organizations such as IES.

This distinction matters because an LED fixture can operate normally and still be unsuitable or non-compliant for a specific installation. A product may have acceptable electrical performance but lack the required listing, fail local energy-control requirements, produce excessive temporal light modulation, or be incompatible with the selected dimming system.

For project teams, the practical question is therefore not simply whether a fixture is efficient or produces the required lumen output. It is whether the complete lighting system satisfies the electrical, energy, control, and performance requirements that apply to the building and jurisdiction.

Why LED Lighting Requires System-Level Coordination

Incandescent lighting placed relatively few demands on the rest of the electrical system. The lamp itself was essentially a resistive load, and its behavior was largely determined by the supply voltage and the fixture.
LED lighting introduces another layer of electronics. The light source depends on a driver that regulates current or voltage, and many installations also include dimming interfaces, occupancy or daylight controls, low-voltage wiring, and networked communication. Not every project uses all of these components, but each additional layer creates another point where compatibility and compliance have to be checked.

Component

Function

Risks if Poorly Specified
LED driver Converts and regulates incoming power for the LED load Flicker, overheating, poor dimming, reduced service life
Lighting controls Dimming, switching, sensing, and automation Driver incompatibility, unstable dimming, control failures
Low-voltage circuits Supply power or control signals within the lighting system Improper wiring methods, separation, or circuit classification
Wireless / network controls Connect lighting to local or building-wide control systems Interoperability, reliability, cybersecurity, or commissioning issues

This is why LED compliance cannot be evaluated by the fixture alone. The driver, controls, wiring method, product listing, and the requirements of the locally adopted electrical and energy codes may all affect whether the complete system is suitable for a project.

Electrical Safety: NEC, Low-Voltage Lighting, and Class 2 Circuits

Electrical safety for LED installations in the United States is governed by the locally adopted edition of the National Electrical Code (NEC) together with requirements enforced by the local authority having jurisdiction (AHJ).

For low-voltage lighting, NEC Article 411 is particularly relevant because it addresses lighting systems operating at 30 volts or less. Article 725 also becomes important when the installation uses Class 2 or Class 3 power-limited circuits for power or control.

Class 2 circuits limit available voltage and power to reduce the risk of electric shock and fire. Many LED drivers and control systems use Class 2 outputs for this reason, but Class 2 is not a universal requirement for every LED installation.

Compliance therefore depends on the complete system: the luminaire, driver, circuit classification, wiring method, controls, and the way those components are installed. A fixture can operate correctly while still creating a compliance problem if the driver, wiring, or equipment listing does not match the applicable NEC requirements or the conditions of installation.

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Energy Codes and Lighting Control Requirements

Energy-code compliance for lighting in the United States depends on the code adopted by the state or local jurisdiction. For commercial buildings, ANSI/ASHRAE/IES Standard 90.1 is one of the principal technical references used in US energy codes, while other jurisdictions use versions of the International Energy Conservation Code (IECC) or state-specific requirements. California applies its own requirements through Title 24, Part 6.

These codes regulate more than fixture efficiency. They also address how lighting is controlled during normal building operation. Depending on the space type and applicable code, requirements can include occupancy-based shutoff or reduction, automatic shutoff, daylight-responsive controls, and limits on lighting power. The current 2025 edition of ASHRAE 90.1 continues to strengthen daylight-responsive and occupancy-control provisions. ASHRAE

This means that an efficient LED fixture does not automatically make a project energy-code compliant. The fixture, driver, sensors, dimming strategy, and control logic have to work together in the manner required by the locally adopted code.

California JA8: Efficiency, Color Quality, Dimming, and Flicker

California’s Title 24, Part 6 includes specific lighting requirements for residential dwelling units. The current 2025 Energy Code applies to permit applications submitted on or after January 1, 2026, and uses Joint Appendix JA8 to define qualification requirements for high-efficacy light sources.

JA8 goes beyond basic energy efficiency. Depending on the product category, it addresses several characteristics that affect real-world performance:

  • luminous efficacy

  • color quality

  • dimming behavior

  • flicker

  • power factor

  • start time

  • audible noise

For qualifying light sources not subject to separate Title 20 color-rendering requirements, the current criteria include CRI of 90 or higher, R9 of 50 or higher, and nominal CCT of 4000 K or less.

JA8 also requires light sources to be dimmable to 10% light output. LED sources designed for forward phase-cut dimmers must meet NEMA SSL 7A compatibility requirements.

One of the more practical requirements concerns flicker. Reduced-flicker operation is defined as less than 30% amplitude modulation at frequencies below 200 Hz, and testing is performed both at full output and at 20% light output.

This matters because a source can appear stable at full brightness and behave very differently once dimmed. For project teams, JA8 therefore provides a useful example of how compliance can address not only efficiency, but also color quality, controls, and actual operating behavior.

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A Working LED Fixture Can Still Be Non-Compliant

A fixture that turns on, dims, and appears to operate normally is not necessarily compliant for a US project. Functional performance and regulatory compliance answer different questions.

Several separate checks may apply:

  • Product safety: the luminaire, driver, retrofit kit, or power supply may need evaluation to the applicable safety standard by a Nationally Recognized Testing Laboratory. OSHA recognizes standards such as UL 1598 for luminaires, UL 1598C for LED retrofit conversion kits, UL 1310 for Class 2 power units, and UL 8750 for LED equipment used in lighting products. UL is not the only acceptable certification organization; other OSHA-recognized NRTLs can evaluate products within their approved scope. 
  • Electrical installation: even properly evaluated equipment must be installed in accordance with the locally adopted NEC requirements, the product’s installation conditions, and the requirements of the authority having jurisdiction.
  • Energy-code compliance: an efficient fixture may still fail project requirements if the required controls, dimming, automatic shutoff, daylight response, or other energy-code provisions are missing.
  • Application-specific performance: flicker, color quality, dimming range, glare, and control compatibility may still make a product unsuitable for the intended space even when basic electrical requirements are satisfied.

California provides a clear example. Under the 2025 Energy Code, luminaires and light sources used in applicable residential installations must satisfy JA8 certification and marking requirements, subject to defined exceptions. JA8 qualification can include the light source and its LED driver as a tested combination, and inseparable luminaires may need the entire luminaire to meet the applicable requirements.

This distinction becomes particularly important with imported fixtures and retrofit products. A specification sheet may show the correct voltage, wattage, lumen output, and even individual certified components, but that does not automatically establish that the complete product configuration is acceptable for the intended installation.

For project review, the relevant question is therefore not simply:

“Does the fixture work?”

It is:

“Is this specific fixture, driver, control combination, and installation method documented for the requirements that apply to this project?”

LED Flicker, Temporal Light Modulation, and Visual Comfort

What is commonly called LED flicker is more accurately described as temporal light modulation (TLM): repeated changes in light output over time.

LEDs respond to changes in electrical current almost immediately. Because of that, the behavior of the driver, dimmer, and control system has a direct effect on the stability of the emitted light. Poorly matched components can create significant modulation even when the fixture appears to operate normally.

TLM can produce several different visual effects:

  • Direct flicker, typically associated with lower modulation frequencies and perceived as visible instability in the light.
  • Stroboscopic effect, where moving objects appear discontinuous or visually distorted under modulated light.
  • Phantom array effect, which can become noticeable during rapid eye movement and may appear as repeated images or patterns.

The US Department of Energy notes that direct flicker is primarily associated with frequencies up to about 80 Hz, while stroboscopic and phantom-array effects can remain perceptible at substantially higher frequencies. This is why frequency alone is not enough to describe LED flicker performance. Modulation depth, waveform, dimming level, and the interaction between the driver and controls also matter.

Historically, IEEE 1789-2015 provided frequency-dependent recommendations intended to reduce potential adverse effects from LED modulation. The document remains an important reference in the development of flicker guidance, but IEEE moved it to Inactive-Reserved status in March 2026. It should therefore be treated as an influential recommended practice rather than a current mandatory lighting standard. 

Current lighting practice increasingly evaluates TLM through more specific metrics and guidance. The ANSI/IES TM-39-25 technical memorandum addresses the measurement and specification of visual responses to TLM and provides a more modern framework for evaluating metrics such as SVM and other visual-response measures.

For project teams, the practical point is straightforward: a claim such as “flicker-free” should not be accepted without supporting performance data. Flicker behavior should be evaluated under the actual operating conditions of the system, including dimmed states, because driver and control performance can change significantly as light output is reduced.

Why LEDs Can Flicker More Than Incandescent Lamps

Incandescent lamps and LEDs respond very differently to changes in electrical current.

An incandescent filament has thermal inertia. Even as the AC waveform passes through zero, the filament remains hot and continues producing light. This naturally smooths much of the variation in light output, which is why incandescent lamps usually show relatively shallow modulation even though the electrical supply itself is alternating.

LEDs behave differently. Their light output responds to current changes almost immediately, with very little persistence. If the driver does not sufficiently smooth the electrical waveform, the light output can rise and fall sharply with the current. In extreme cases, modulation can approach the full range from nearly off to full output.

The driver therefore plays a critical role. Its electronics determine how well the LED output is regulated and how the system responds to dimming. Some dimming methods, particularly poorly matched phase-cut controls or pulse-width modulation strategies with deep modulation, can introduce additional temporal light modulation.

This is why two LED fixtures with similar wattage, lumen output, and color temperature can behave very differently when dimmed. The visible result depends not only on the LED chips, but on the driver design, control method, modulation frequency, and depth of modulation.

The practical consequence is straightforward: replacing an incandescent or fluorescent source with LED should not be evaluated only by matching wattage or light output. Driver and dimmer compatibility can determine whether the new system provides stable light or introduces flicker that was not present before.

How LED Flicker Is Measured

There is no single number that fully describes LED flicker. Temporal light modulation depends on modulation depth, frequency, waveform, and the operating condition of the luminaire. This is why technical specifications may include several different metrics.

Metric

What It Measures

How to Read It
Percent Flicker / Modulation Difference between maximum and minimum light output relative to the overall output Useful as a simple measure of modulation depth, but does not account well for frequency or waveform
Flicker Index Relationship between the light waveform above and below its average level Provides more waveform information than Percent Flicker, but is an older metric and should not be used alone
PstLM Short-term visibility of direct flicker under normal viewing conditions Used to evaluate whether modulation is likely to be perceived as visible flicker
Stroboscopic Visibility Measure (SVM) Probability that modulation will make moving objects appear discontinuous or distorted Particularly relevant where people or machinery are moving under LED lighting
Modulation Frequency Number of light-output cycles per second, expressed in hertz Important context, but frequency alone does not determine whether a lighting system will produce visible TLM effects

A specification such as “flicker-free” is therefore not very informative unless the manufacturer provides actual measurement data and explains the conditions under which the product was tested.

Dimming deserves particular attention. A luminaire that performs well at full output may show substantially more modulation at lower light levels because the driver and control method behave differently. California JA8, for example, evaluates reduced-flicker performance not only at full output but also at 20% light output.

For project review, the useful question is not simply whether a fixture flickers. It is which TLM metrics were measured, at what operating level, and with which driver and control configuration.

Retrofit Mistakes That Cause Flicker Problems

LED retrofits often fail at the interface between the new luminaire and the existing control system.

A fixture may physically replace a fluorescent or incandescent source without difficulty, yet the electrical behavior of the new LED driver can be completely different. Existing dimmers, sensors, switching devices, or control wiring may not operate correctly with the replacement equipment.

Typical symptoms include:

  • flicker or flashing at certain dimming levels
  • buzzing from the driver or control device
  • uneven dimming between luminaires
  • lights that drop out before reaching the intended minimum level
  • delayed start, ghosting, or unexpected behavior when switched off
  • unstable operation when occupancy or daylight controls are activated

The underlying cause is usually not the LED source alone. It is the interaction between the driver, control method, minimum load, dimming protocol, and existing electrical system.

For example, a phase-cut dimmer that worked acceptably with incandescent lamps may not provide stable operation with a particular LED driver. Likewise, a fluorescent system using 0–10 V controls may require verification that the replacement LED driver accepts the same control signal and responds correctly across the full dimming range.

This is why a retrofit should not be evaluated only by fixture dimensions or wattage. The existing control method, driver compatibility, dimming range, and operating behavior should be reviewed before the replacement equipment is specified.

Correcting a mismatch after installation can require new drivers, replacement controls, rewiring, or recommissioning of the lighting system.

LED Lighting Regulations in the US

Lighting for Schools and Healthcare Facilities

Schools and healthcare facilities illustrate why LED lighting cannot be evaluated by efficiency alone. Both environments involve long periods of occupancy, but the required light level and quality can change substantially within the same building.

Educational Facilities

The current ANSI/IES RP-3-26 addresses lighting for educational facilities, while the US Department of Energy’s 2024 school-lighting guidance provides useful quantitative benchmarks for retrofit and specification work.

For general classroom applications, DOE cites IES recommendations of 30 to 50 footcandles, or approximately 300 to 500 lux, on desks and other task surfaces.

That number should not be treated as the only design criterion. DOE specifically notes that light distribution also matters. Vertical illumination needs to be considered so that teachers, whiteboards, walls, and instructional material remain clearly visible. LED replacements can produce very different distributions from existing fluorescent systems even when measured horizontal illuminance appears adequate.

For school LED projects, the specification should therefore consider:

  • 300–500 lux (30–50 fc) on typical classroom work surfaces

  • vertical illumination for whiteboards and teaching surfaces

  • glare and fixture distribution

  • flicker and temporal light modulation

  • dimming and separate control of teaching zones

  • - interaction between electric lighting and daylight

Dimming also has a practical role beyond energy savings. DOE recommends considering it for classroom flexibility and specifically identifies areas such as special-education classrooms, counseling rooms, and school nurse offices as priorities where adjustable lighting can be particularly useful.

This is also why simply replacing fluorescent troffers with LED fixtures on a one-for-one basis can be problematic. DOE recommends evaluating actual light levels and distribution before completing a building-wide retrofit rather than assuming equivalent wattage or fixture dimensions will produce equivalent lighting conditions.

Healthcare Facilities

Healthcare provides an even clearer example of why a single “recommended lux level” is not enough.

The current ANSI/IES RP-29-25 addresses lighting for hospitals and healthcare facilities, including task visibility, glare, color, controls, comfort, safety, and flicker. Actual illumination requirements vary substantially according to the clinical task and location.

For a quantitative US reference, the US Department of Veterans Affairs Lighting Design Manual specifies several different maintained illumination levels within a single patient room:

  • 50 lux (5 fc) for general ambient illumination at the floor

  • 400 lux (40 fc) for patient reading

  • 500 lux (50 fc) for examination at the patient bed

  • 30 lux (3 fc) for night observation

  • - approximately 2 lux (0.2 fc) for night lighting along the path to the toilet or corridor

The same VA guidance specifies 500 lux (50 fc) ambient illumination for diagnostic imaging rooms, with different task levels within the room depending on the activity.

Those figures show why healthcare lighting is typically divided into zones and operating modes rather than designed around one fixed output level.

There is also a practical reason for emphasizing controls. In a DOE-supported survey of 252 nurses across four hospitals, 68% reported using supplemental lighting in patient rooms, and 24% specifically mentioned using a flashlight. Nurses ranked light level as the most important lighting attribute affecting their professional tasks, while controls ranked second.

For LED specification, that translates into a requirement for much more than adequate lumen output. The system may need to provide high task illumination for examinations, much lower nighttime levels, controlled glare for a reclining patient, reliable dimming, appropriate color performance, and stable operation throughout the control range.

IES recommendations are not automatically mandatory building-code provisions in every jurisdiction. They provide application-specific professional design criteria, while legal requirements still depend on the adopted codes, project specifications, and the authority having jurisdiction.

Smart Lighting and IoT Compliance

Connected lighting systems can combine luminaires, occupancy and daylight sensors, gateways, mobile applications, cloud services, and building automation platforms. Depending on the project, communication may use technologies such as Bluetooth, Zigbee, Wi-Fi, or other wired and wireless protocols.

The current ANSI/IES LP-12-26, Lighting Practice: Lighting Systems and the Internet of Things, treats connected lighting as an IoT ecosystem rather than simply a wireless control feature. The document covers system architecture, integration throughout the project lifecycle, data analytics, security, energy considerations, and newer technologies such as Bluetooth, Li-Fi, Ultra Wide Band, and LTE-M.

For a US project, several additional issues may therefore need to be reviewed:

  • Interoperability and commissioning. Sensors, drivers, gateways, and control software need to communicate reliably and continue operating as intended after installation.
  • Wireless equipment compliance. Wi-Fi and Bluetooth transmitters are intentional radiators subject to FCC equipment-authorization requirements under Part 15 before they can be marketed in the United States.
  • Cybersecurity. NIST IR 8259 Rev. 1, published in 2026, recommends cybersecurity activities across the IoT product lifecycle, including development, support, risk assessment, and information provided to customers.
  • Privacy. Privacy obligations depend on what information the system collects and who operates it. In California, the CCPA applies to covered businesses handling personal information that can identify, relate to, or reasonably be linked with a consumer or household. It is therefore not a blanket requirement for every smart-lighting installation.

A connected LED system can therefore be electrically compliant and still have unresolved issues at the network or data layer. For specification purposes, it is useful to verify not only the lighting hardware, but also the wireless module authorization, software and firmware support, cybersecurity documentation, data flows, and compatibility with the building automation platform.

What to Check on an LED Specification Sheet Before Approval

An LED specification sheet should be reviewed as more than a product brochure. Before a fixture is approved for a US project, the document should provide enough information to verify electrical suitability, control compatibility, lighting performance, and any project-specific code requirements.

A practical review should cover several areas.

  • Product safety listing. Verify the applicable NRTL listing for the complete product or assembly, not only individual internal components. Common standards include UL 1598 for luminaires, UL 1598C for LED retrofit conversion kits, UL 1310 for Class 2 power units, and UL 8750 for LED equipment used in lighting products. OSHA recognizes multiple NRTLs, so UL is not the only acceptable certification body.

  • Electrical ratings. Check input voltage, frequency, wattage, driver output characteristics, power factor, environmental rating, and whether the driver is identified as Class 2 where that classification is relevant to the installation.

  • Dimming and controls. The specification should state the supported control method, such as forward phase-cut, reverse phase-cut, 0–10 V, digital control, or another protocol, together with the usable dimming range. “Dimmable” by itself is not enough information to establish compatibility.

  • Flicker and temporal light modulation. Look for measured data rather than a general “flicker-free” claim. Depending on the application, useful information can include Percent Flicker, PstLM, SVM, modulation frequency, and test conditions. DOE notes that multiple metrics may be needed because different metrics describe different TLM effects.

  • Color performance. Review CCT, CRI, and, where relevant, R9 or more detailed color-quality data. For California JA8 products that are not subject to separate Title 20 color-rendering requirements, the current criteria include CRI ≥90, R9 ≥50, and CCT ≤4000 K.

  • Project-specific energy-code data. If the product is being used in a jurisdiction with additional requirements, verify the actual certification or qualification rather than relying on generic efficiency claims. California JA8, for example, requires a minimum dimming level of 10%, identifies compatible control methods, and limits flicker to less than 30% modulation at frequencies up to 200 Hz at both full output and 20% light output.

For connected lighting, the review may also need to cover the wireless module, supported communication protocol, FCC authorization, firmware support, cybersecurity documentation, and integration requirements for the building control platform.

The final point is important: a specification sheet is evidence, not approval by itself. Product listing records, installation instructions, test reports, control compatibility data, and project submittals may still need to be reviewed separately.

For a project team, the approval question should therefore be:

Does the documentation verify that this exact fixture, driver, and control configuration is suitable for the electrical, energy-code, and performance requirements of this project?

Conclusion

LED lighting compliance in the United States is not defined by a single standard. It is the result of several layers of requirements that apply at different stages of a project.
A lighting system may need to satisfy:

Product Safety & Listing Requirements

NEC & Local Electrical Installation Rules

Adopted Energy Code Requirements
Applicable product safety certification, listing, and documentation requirements. Electrical installation must comply with the NEC edition adopted by the local jurisdiction and AHJ requirements. Lighting must meet the energy code adopted for the project jurisdiction, including applicable control requirements.

Lighting Performance Criteria

Driver & Control Compatibility

RF, Cybersecurity & Data Requirements
Color quality, dimming behavior, flicker, and temporal light modulation should be evaluated for the intended application. Drivers, dimmers, sensors, and control systems must be verified for reliable operation as a complete system. Connected lighting may introduce additional wireless, cybersecurity, software, and data-privacy requirements.

These categories should not be treated as interchangeable. A luminaire can be electrically safe but fail an energy-code requirement. It can meet the applicable code and still produce poor dimming or excessive flicker. A connected fixture can perform correctly as a light source while introducing unresolved network or wireless-compliance issues.

For designers, contractors, developers, and owners, the most useful approach is therefore to review LED lighting as a complete system and verify the relevant documentation before products are approved or installed.

A Priori Source supports the selection and supply of LED lighting and control systems for US projects, including coordination of technical specifications and available compliance documentation with project requirements.

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FAQ

How do regulated LED devices ensure user protection and meet safety standards?

User protection in an LED installation depends on several layers working together. Product safety evaluation addresses risks such as electric shock, overheating, and fire. The NEC governs how equipment is installed, while locally adopted energy codes can impose additional requirements for controls, automatic shutoff, and dimming. For low-voltage systems, Class 2 power limitations may be relevant, but Class 2 is not required for every LED installation. The complete fixture, driver, wiring method, controls, and applicable product listing should be evaluated for the specific project. Lighting quality is a separate consideration. Flicker, dimming behavior, glare, and color performance can affect visual comfort even when the electrical installation itself is compliant.

What are the main LED lighting standards and code requirements in the United States?

There is no single national “LED lighting standard.” Different requirements address different parts of the system. For a typical US project, the relevant framework may include:

  • NEC for electrical installation and safety
  • UL or other NRTL standards for applicable product safety evaluation and listing
  • ASHRAE 90.1, IECC, or another locally adopted energy code for lighting power and control requirements
  • California Title 24 and JA8 for applicable projects in California
  • IES guidance for application-specific lighting performance
  • TLM and flicker metrics such as PstLM and SVM when temporal light modulation is being evaluated

The applicable requirements depend on the jurisdiction, building type, product configuration, and intended application.

What does “flicker-free” actually mean on an LED specification sheet?

“Flicker-free” by itself is not a precise technical specification. LED light output can vary with frequency, modulation depth, driver design, dimming level, and the control method being used. A stronger specification provides measured data such as Percent Flicker, PstLM, SVM, modulation frequency, and the conditions under which testing was performed. Dimming is especially important. A fixture that performs well at full output can show significantly more temporal light modulation at lower levels. For project approval, the useful question is therefore not whether the manufacturer uses the term “flicker-free,” but what was measured, at what output level, and with which driver and control configuration.

Can an LED fixture work normally and still fail code compliance?

Yes. A fixture can turn on, dim correctly, and appear to perform well while still failing one or more project requirements. Compliance can depend on factors that are not visible during normal operation, including the applicable product listing, NEC installation requirements, the locally adopted energy code, control requirements, and project-specific conditions such as California JA8. A common example is a fixture assembled from individually listed components. The driver or LED module may carry a recognized certification, but that does not automatically mean the complete luminaire configuration has been evaluated or is acceptable for the intended installation. The correct review therefore considers the complete fixture, driver, controls, wiring method, documentation, and the requirements of the local authority having jurisdiction.

How can you tell whether LED flicker is caused by the driver, dimmer, or wiring?

The operating conditions usually provide the first clue. If flicker appears mainly when the light is dimmed, the issue is often related to driver and dimmer compatibility, minimum load, or the selected dimming method. If one fixture flickers while identical fixtures on the same circuit remain stable, the driver or luminaire itself becomes a stronger suspect. If several fixtures flicker together, including at full output, the investigation should also consider supply-voltage fluctuations, loose connections, neutral problems, shared loads, or other wiring conditions.

Typical diagnostic steps include:

  • testing the fixture at full output and at several dimming levels
  • temporarily bypassing or replacing the dimmer with a compatible control
  • comparing affected fixtures with identical fixtures on the same circuit
  • checking driver specifications and approved dimmer compatibility
  • measuring supply voltage and inspecting wiring connections if the problem affects multiple luminaires

Flicker troubleshooting should therefore focus on the complete electrical and control system rather than assuming that the LED light source itself is defective.