What to Look for in a Lighting System Supplier (a buyer's notes after $42K of mistakes)

"What's your per-unit price on the LED power supply?"

That was 2018. I was sourcing fixtures for a campus retrofit — around 1,800 heads across three buildings. I sent the RFQ to six suppliers, got quotes back, ranked them by dollars-per-watt, picked the cheapest, and moved on.

Six months later we started commissioning. 340 fixtures on a single DALI network. A quarter of them would not individually address. The "DALI driver" on the spec sheet meant the driver accepted a DALI signal — it did not support individual addressing of the ballast/driver on the bus, which was the entire reason we had specified DALI in the first place.

We re-sourced the drivers. Total loss landed around $42,000 once you count labor, the three-week delay, and the liquidated damages clause the GC invoked. I remember the invoice total. I remember the project manager's face more.

That mistake is why I keep a printed pre-check sheet taped inside my sourcing binder. Below is what's actually on it.

The mistake nobody puts in the spreadsheet

Here's what I got wrong, and what most people in the same seat get wrong: I treated the LED driver as a component. The driver is the lighting system. Once you pick the driver, you have locked the dimming curve, the flicker behavior at low end, the inrush current, the surge protection, the thermal de-rating curve, and the failure mode of every fixture on that circuit.

So the actual question is not "what to look for in a lighting system supplier." It's "which decisions do you make at the supplier, and which decisions you're making at the driver." If you haven't separated those two, price comparison is theater.

Reason 1: "DALI driver" is a label, not a specification

DALI is standardized under IEC 62386, which is maintained by the IEC and by the Digital Illumination Interface Alliance (DiiA) for the certification program. A driver can legitimately be "DALI" in three very different ways:

• DALI-2 certified — passed DiiA's test suite. Interoperability is the point of the certification.
• DALI-compatible / "supports DALI signal" — accepts a DALI bus signal but may not implement the full command set. Often fails multi-vendor mixed-bus scenarios.
• DALI application — DALI across a proprietary run of the manufacturer's own gear. Works fine until you add a second brand.

Ask for the DiiA certification reference number, not the marketing word. If the supplier cannot produce it in under an hour, the driver is not DALI-2 certified. That's not a sales call — that's a procurement filter.

This is also where the choice of a known driver platform matters. When you're evaluating DALI drivers — Tridonic, for example, publishes the DiiA certification references for its DALI-2 driver lines — the point isn't the brand name. The point is that a documented interoperability footprint exists, so your control system integrator can predict behavior before install. A no-name driver at 30% cheaper has no such paper trail. In a 200-fixture segment, you don't want to be the one doing the discovery testing on-site.

Reason 2: The "manufacturer" is often a private label

Most people assume that a supplier selling "their" lighting system actually builds it. Increasingly, that's not the case. The supplier is an ODM reseller: they buy the driver from one factory, the housing from another, the lens from a third, put their own label on the box and their own logo on the instruction sheet.

That's not a problem by itself. It is a problem when nobody in the supply chain tells you.

When you buy a private-label lighting system, you need to know specifically:

• Who actually manufactures the LED power supply — the name on the factory door, not the brand on the label.
• Who holds the UL / ENEC / CE declaration of conformity. If the certificate is held by the ODM factory, the ODM can change the driver without telling the brand, which can void your CE mark on the finished luminaire.
• Whether the ODM has a change-notification clause in its contract with the brand. Many do not. Many brands do not ask.

Half of my $42,000 mistake traces back to this. The supplier was private-labelling a driver from a factory I had never heard of. When I asked about the DALI addressing mode, the sales rep genuinely did not know — they had never opened the box.

To be fair, private label is not automatically worse than a vertically integrated supplier. Some of the best-run sourcing programs I've seen are ODM-based, because the brand focuses on integration and support rather than on running a factory. The difference is transparency: an ODM-based supplier who tells you who the OEM is, and puts the change-notification in writing, is generally easier to work with than a "manufacturer" who is vague about their own production.

Reason 3: The real cost lives in the documents, not the invoice

The cheapest quote I ever accepted in 2021 was roughly 18% below the next bid. Total delivered cost came in about 22% above the next-most-expensive option, because the missing pieces were all on the document side:

• No photometric .ies files for the finished luminaire — we had to have third-party testing done to satisfy the client's lighting designer: roughly $3,400.
• CE declaration referenced a driver model that had been discontinued. The supplier shipped a "drop-in replacement" with slightly different surge tolerance. Installation report had to be reissued: 4 days of the electrical contractor's time.
• DALI-2 certification not actually held for the specific driver SKU shipped. Different SKU number, same family name. Cost us a re-test at the commissioning stage.

I've learned to ask "what's NOT included" before I ask "what's the price." Phrasing it that way takes some getting used to in a first email. Do it anyway.

The vendor who lists every fee and document upfront — even if the headline number looks higher — is usually the one who costs less by the time the project closes out. I've tracked this across roughly 40 commercial projects now. The correlation is not perfect. It's strong enough that I won't accept a quote anymore that omits the compliance line items.

What I actually check now, in order

1. DiiA certification reference number for the specific driver SKU — not the family. Ask in writing.
2. Named manufacturing source for the driver inside a private-label system. If they won't name it, treat it as unknown-brand risk and price accordingly.
3. Who holds the declaration of conformity and whether the ODM has change-notification in their supply contract.
4. Programmable output range and default curves — because a driver that programs 200–1050mA is worth more than a fixed 700mA unit at the same price, but only if you actually know the range.
5. Photometric files, surge rating, and thermal de-rating curve for the finished assembly, not the bare driver.
6. Warranty carve-outs — normally the first place unclear sourcing shows up. "5-year warranty" rarely means 5 years on the driver inside a sealed fixture.

That's the whole list. It takes about an hour per supplier to run and has saved us from two confirmed mispicks since I started using it consistently in early 2023.

Two things I want to be honest about

I learned this list working on commercial and light-industrial projects in the 200-fixture to 2,000-fixture range. If you're sourcing municipal, hazardous-location, or stadium-scale, your priorities will shift — surge and IP ratings carry far more weight there, and some of my weighting above won't apply.

Also, everything here is written relative to the market as of late 2024. DiiA has been tightening the DALI-2 certification process, and the ODM/label landscape shifts faster than most procurement docs assume. Verify current certification status and current pricing before you use any of this as a hard filter. I'll update the sheet when I find it needs updating — which is usually whenever a supplier has found a clever new way to omit a column.