I Learned This the Expensive Way

I've been handling lighting and power supply orders for about nine years, and in that time I've made 13 documented mistakes. Together they cost me roughly $6,900 in wasted labor and materials. The one I'm most embarrassed about is also the most useful: I bought a “MEAN WELL” LED power supply that wasn't a MEAN WELL. Same branding. Same model number. Not the same product.

Search for a “mean well led power supply” and you'll see listings that make it look like a commodity. Many are fine. Some are not. This isn't a comparison of MEAN WELL against a random cheap brand—it's a comparison of the genuine units I use now against the counterfeits that caused my mistakes. Same label, same case, different behavior.

I'll compare them on four dimensions: output accuracy, dimming, installation, and total cost. Then I'll give you the checklist I use now.

Dimension 1: What a Label Says vs. What a Supply Does

It's tempting to think a power supply is a power supply. Match voltage, match current, plug it in. But the first difference appears before the product is even powered.

The MEAN WELL 24v 5a power supply I use most often is the LPV-120-24. According to the official product page on meanwell.com, it's rated 24V at 5A, IP67, constant voltage. A counterfeit copy I bought weighed noticeably less. Under a 3.5A load, it output 22.8V instead of 24V. The light result was subtle color shift in the middle of the run and visible after a few feet.

When I swapped in a genuine LPV-120-24, the output held at 24.0V under load. I kept my meter on the terminals, waiting for the fake behavior. It didn't come.

For constant-current fixtures, the danger is even bigger. I once replaced the driver inside an Italian chandelier with a counterfeit LPC-60-700. The current drifted from 620mA to 780mA. The chandelier flickered on its lowest settings, and the restaurant owner saw it immediately. That mistake cost me $480 in rework labor, plus the price of a genuine replacement.

What most people don't realize is that a counterfeit label can match the model number but not the internal design. The output type is the first thing to verify: constant voltage or constant current. If the product doesn't say which one it is, it isn't an LED driver you can trust.

Dimension 2: Dimming and the “3-in-1” Claim

Dimming is where a fake reveals itself. One reason I spec genuine MEAN WELL drivers is the 3-in-1 dimming capability: resistor, PWM, and 1-10V. It lets one driver serve several control systems. The genuine unit follows the signal. The counterfeit doesn't.

What most people don't realize is that “dimmable” is not the same as “has a dimming circuit.” A fake I tested had control wires, but no response on either PWM or 1-10V. The genuine driver, in the same fixture, dimmed smoothly down to about 10% before cutting off.

The 3-in-1 dimming resistor range matters more than it sounds. On the genuine unit, I can read the value from the datasheet and know exactly what dimming level to expect. The counterfeit had no resistance response at all.

For a dimmable Italian chandelier, this isn't a technical footnote. The difference is between a warm, controlled dining room and a flickering conversation piece. That's a bad place to save money.

Dimension 3: How to Run Under Cabinet Lighting (Without Losing a Weekend)

When people ask how to run under cabinet lighting, they usually want a wiring diagram. But the question that matters is the power supply. Most LED strip lights run on 24V constant voltage, so the driver must be constant voltage as well.

How to run under cabinet lighting, in a practical order:

  1. Confirm the strip voltage. If it says 24V, don't use a constant-current driver.
  2. Run 18/2 or 16/2 low-voltage cable from the driver to each under-cabinet zone. Parallel connections are better than one long daisy chain.
  3. Mount the driver in a ventilated spot. Above the cabinets or in a covered service space works. Don't bury it in insulation.
  4. Label the power supply side, not just the strip, so the next person knows what's feeding what.

The reason I put “power supply” first is personal. I installed 40 feet of strip lights with a counterfeit supply once. The output sagged at the far end, the driver got warm above the range, and the lights flickered after 20 minutes. The genuine LPV-120-24 took over that exact spot and never blinked.

For an outdoor light flood, the same lesson hit harder. The counterfeit claimed IP67, but water entered through a poorly sealed screw hole and killed it after one rain. The genuine IP67 case is potted. You can see the difference as soon as you open it, but by then it's usually too late.

Dimension 4: Total Cost, Callbacks, and Reputation

The price gap between a genuine MEAN WELL LED power supply and a counterfeit is often $15 to $25. On a $3,700 lighting retrofit, that's less than 1 percent. The cost of a callback is usually $300 to $600 and a chunk of trust.

Here's my mistake log entry from 2024: an $18 counterfeit “MEAN WELL” caused a 2 a.m. failure in a retail shop. The emergency electrician billed $450 before I even heard about it. That didn't count the missed opening, the refund, or the conversation I had to have with a customer who had previously trusted me.

The lesson is consistent with how I define quality: the light is the brand. A smooth light flood, a stable under-cabinet row, a dimmable Italian chandelier—these are what the customer remembers. They won't say nice power supply, but they'll feel the difference.

“A counterfeit can work for two years and then die. That's the trap. One bad failure erases every dollar you saved.”

I'm not saying every cheap unit fails. But as a contractor, you don't just buy a power supply. You buy the certainty that it does what the label says. Certainty is the actual product.

What I Check Now

If you're asking how to run under cabinet lighting or you're replacing a driver in a delicate fixture, start by verifying the supply before installing it.

  • Buy from an authorized MEAN WELL distributor, not only from a marketplace listing.
  • Compare the printed model with the specifications on meanwell.com.
  • If the label shows a safety mark, search the file number in the UL Product iQ database. A real mark is traceable; a sticker isn't.
  • Weigh the unit if possible. A big gap from the official weight is a warning.

Per FTC advertising guidance (ftc.gov), claims about products have to be truthful and substantiated. A counterfeit driver labeled as a certified model is the opposite of that. If you install it, your name is the one on the invoice.

Searching for “mean well led power supply” is a reasonable first step. Making sure you actually receive one? That's the job.