How LED lighting is made
An LED luminaire has three working parts: the LED board, the driver and the heat path. LED packages are placed on a metal-core circuit board by pick-and-place machines and soldered in a reflow oven. The board is fixed to an aluminium housing, die-cast or extruded, that carries the heat away, with thermal paste or a pad between them. The driver converts mains AC to the constant current the LEDs need; many Indian assemblers buy drivers from specialist makers, others build their own. Optics or diffusers, gaskets and cable glands are fitted, and finished fittings go through an ageing rack, where they burn for hours, and production tests before packing.
The cost is mostly in the LEDs and the driver, and both can be changed without changing how the product looks. A batch built with lower-bin LEDs gives less light; a cheaper driver can mean flicker, a low power factor or early failure. India exported US$315.6 million under HS 9405 in FY2025-26 according to Department of Commerce TradeStat; the figure is provisional and the heading also covers non-LED and decorative lighting. We have not found an official source naming LED lighting clusters, so we name no town.
What we check on LED lighting
| Check | How it is checked | What fails |
|---|---|---|
| Hi-pot (electric strength) | Factory's tester applied between live parts and accessible metal on every sampled unit; set voltage, time and trip current recorded | Breakdown or trip |
| Earth continuity | Factory's earth bond tester on every sampled Class I fitting, from the earth terminal to the housing | Resistance above the set limit; earth wire not fixed to the housing |
| Wattage and power factor | Sampled units run at rated voltage on the factory's power meter; readings compared with the label and datasheet | Power well off the label; power factor below the specification |
| Driver identity | Driver opened up or read through the housing: make, model, output current and approvals compared with the type-test report and approved sample | Different driver or different output current |
| LED board | LED count, package type and board marking compared with the approved sample; thermal pad or paste present | Fewer LEDs; different package; no thermal interface |
| Light colour and output | Units lit side by side against the golden sample; colour consistency and dead LEDs checked; samples sealed for photometry | Visible colour difference; dead or dim LEDs |
| IP construction | Gaskets, glands, potting and screws checked as built against the IP-tested design | Missing gasket; gland that does not grip the cable |
| Labels and packaging | Rating label, CE or UKCA, WEEE bin, energy label and EPREL QR code on light-source packaging, instructions | Label data that differ from the test report or EPREL entry |
Lumen, CCT, CRI and flicker: what needs a lab
Total luminous flux, efficacy, colour temperature (CCT) and colour rendering (CRI) are measured in an integrating sphere or with a goniophotometer, under controlled temperature and stabilisation. Some factories own a sphere and we can witness its readings, but those are indicative. Where the claim matters, for a tender, a retailer or an energy label, we pull samples at random, seal them and send them to an ISO/IEC 17025-accredited photometric lab through lab testing coordination, then compare the lab report with the label.
Flicker is mostly a driver question. Under the EU Ecodesign Regulation for light sources, mains-powered light sources must meet limits on visible flicker (PstLM of 1.0) and stroboscopic effect (SVM), and the SVM limit tightened from 0.9 to 0.4 on 1 September 2024. Both need a lab instrument. On site we make sure the driver is the one that was tested, because a substituted driver is the usual reason a fitting that passed in the lab flickers in the shipment.
Photobiological safety (IEC 62471), temperature rise, EMC emissions and the full IEC 60598 safety tests are type tests for the lab, not inspection checks.
Ecodesign, EPREL and other market rules
In the EU, Regulation (EU) 2019/2020 sets ecodesign requirements for light sources and separate control gear, and Regulation (EU) 2019/2015 sets the rescaled A to G energy label; both have applied since 1 September 2021. Light sources need the energy label, and suppliers must register each model in the EPREL product database before placing it on the market; the label's QR code links to the entry. Luminaires are "containing products": since 25 December 2019 they carry no energy label, but the supplier must state which light sources they contain, and if the light source or control gear cannot be removed for checks without permanent damage, the whole luminaire is treated as a light source. We check the label, the EPREL entry and the luminaire documentation against the model shipped.
Safety follows the IEC 60598 series for luminaires, IEC 62031 for LED modules and IEC 61347-2-13 for LED drivers, under the Low Voltage and EMC Directives; RoHS and WEEE also apply. For the US, luminaires are commonly listed to UL 1598 and LED equipment to UL 8750, with FCC Part 15 for electromagnetic emissions; see UL and ETL listing. DLC and ENERGY STAR are voluntary programmes some buyers require.
Common defects in LED lighting
| Defect | Why it matters | Class |
|---|---|---|
| Hi-pot failure or broken earth on a Class I fitting | Shock risk | Critical |
| Driver not the one in the test report | Safety, EMC and flicker results no longer apply | Critical |
| CE, UL or energy label without supporting test report or EPREL entry | Cannot lawfully be sold as marked | Critical |
| Wattage or power factor far from the label | Energy and lumen claims not met | Major |
| Missing gasket or loose gland on an IP-rated fitting | Water entry and failure outdoors | Major |
| Dead LEDs or visible colour mismatch | Customer rejects the installation | Major |
| Scratched diffuser, paint marks on housing | Appearance | Minor |
Packing, transit and your purchase order
Diffusers and glass covers crack when cartons are crushed, and heavy die-cast flood and street lights break their own packaging if the inserts are weak. The inspector checks inner packing, carton strength and stacking marks, and may carry out a drop test on a packed carton. Look for loose screws or parts rattling in sealed cartons after the ageing rack.
Put these in your purchase order:
- Wattage, lumen output, efficacy, CCT, CRI and beam angle, with tolerances and the lab method for checking them.
- Approved driver make and model, LED package and bin; no substitution without written approval.
- Power factor, flicker requirement, IP and IK rating, operating temperature.
- Markets and marks: CE or UKCA, energy label and EPREL registration, UL or ETL listing.
- Production tests to witness: hi-pot, earth continuity, ageing hours.
- Samples for the photometric lab and who pays for them.
- Packaging, labels, instructions and languages.
Decorative lamps and string lights have their own pages: table and floor lamps and string lights and LED décor. Book an inspection.
Sources
- Department of Commerce, TradeStat: commodity-wise exports (HS 9405, FY2025-26 provisional)
- European Commission: Light sources, Regulations (EU) 2019/2020 and 2019/2015
- Commission Regulation (EU) 2019/2020, ecodesign for light sources and separate control gears (EUR-Lex)
- Commission Delegated Regulation (EU) 2019/2015, energy labelling of light sources (EUR-Lex)
- European Commission: What is EPREL?