The Question I Shouldn't Have Answered So Fast

It was a little after 9 a.m. on a Tuesday in March 2024 when an interior designer I work with forwarded me a rendering and asked: "Can you add a dimmer switch to any light?"

The rendering was a sputnik chandelier — six long arms, brass finish, very mid-century. And it wasn't going in a dining room or a foyer. It was going in a master walk-in closet. A closet chandelier, she said. Her client wanted that "quiet luxury hotel dressing room" feeling: low, warm light at night, full brightness while picking out clothes.

I said yes before I'd even looked at the lighting schedule. "Sure. We'll just put a dimmer on the circuit."

That sentence cost me $860, six days of schedule delay, and a segment of LED strip that I had to replace myself. I've been specifying LEDs and power supplies for seven years, and I've made my share of mistakes — probably six significant ones, totaling around $4,000 in wasted budget. This was the one that finally forced me to write a checklist for my team. I wish I'd written it sooner.

Why I Reached for a Mean Well 24V 10A Power Supply

The fixture itself wasn't complicated. It was a 24V LED system: six small G4-style bulbs plus an integrated strip along the center spine. Measured load, around 72W. When I need a constant-voltage 24V supply, I default to Mean Well. It's not the flashiest choice, but it's been the reliable one on dozens of projects.

My plan was the Mean Well 24V 10A power supply model — the LRS-240-24. It delivers 24V at up to 10A in a compact metal case, and it's affordable enough that contractors don't flinch at the line item. I've installed a lot of them. None has failed on me before or since.

Here's what I missed: the LRS-240-24 is a fixed-output switching power supply. It is not a dimmable driver. And in a dimmed LED system, that distinction is everything.

What I Assumed Wrongly About Dimmers and LED

From the outside, this looks like a dimmer problem. It wasn't. It was a spec problem.

Most people assume a dimmer switch is a dimmer switch. You swap the wall switch, turn the knob, lights go down. That works with incandescent bulbs, and it works with a lot of retrofit LED bulbs that have their drivers built into the base. But when you're feeding a 24V chandelier through an external power supply, the wall dimmer has to talk to that box, not to the fixture. The lamp is just a passenger.

The LRS-240-24 has no dimming interface. Feeding it phase-cut AC from a wall dimmer is like asking a light switch to control a power drill. It isn't wired for that conversation, and no amount of brand reliability fixes a fundamental mismatch.

Three Dimmers, Two Dead Drivers, One Very Unhappy Client

Day one: I had the electrician install a standard leading-edge dimmer. On paper, fine. In practice, the chandelier hummed. Not loudly, but with the kind of low buzz you notice in a quiet walk-in closet — which is exactly where this thing lived. And the lights never got below about 80%.

I told him to swap it for a trailing-edge dimmer. That killed the hum. It also introduced a new problem: below 40%, every LED flickered. Not a subtle shimmer. A strobe. The designer saw it, filmed it, and sent me a video with the kind of caption that makes you put your phone down for a minute.

Then came the pop. That was the LRS-240-24 shutting down after about ten seconds of something that smelled like hot capacitors and regret. It refused to restart.

I was ready to blame Mean Well. I really was. It felt like the brand's fault — the "reliable" supply had died, right? But I checked the product labeling and the serial number, and it was genuine. It didn't fail. I'd asked it to do something it was never designed to do.

The Mean Well Power Supply Distributor Call That Saved the Job

I Googled "mean well power supply distributor" on my phone, ready to file a warranty claim. Instead of firing off an angry email, I called an authorized distributor's tech support line. The engineer asked me two questions:

"Is the driver rated for dimming?"
"I don't know."

"What dimming control does the fixture side expect?"
"There isn't one. It's a chandelier."

The pause on the other end was brief and diplomatic. Then he said, "We need to re-spec. What's the actual load?"

We measured the chandelier: 3A at 24V, so about 72W. The 240W LRS I'd specced was overkill anyway. And overkill doesn't fix compatibility.

He sent me the datasheet and wiring diagram for the Mean Well PWM-120-24 — a 24V constant-voltage LED driver with Mean Well's 3-in-1 dimming. Depending on how you wire it, you can control it three ways: with a resistance, with a PWM signal, or with a 0-10V DC voltage. We picked a 0-10V wall dimmer, and it plugged into the driver's low-voltage terminals instead of the AC line.

Twenty Minutes That Fixed Everything

The installation took less time than the phone call. We removed the LRS-240-24, mounted the PWM-120-24, and ran a single pair of wires from the wall dimmer to the driver's 0-10V control terminals. Done.

The chandelier dimmed from 100% down to about 10%, smoothly, with no flicker at any point. No hum. The client had her closet chandelier moment. It was beautiful — and humbling, because the fix was that simple.

What was complicated was everything I'd assumed to get there. It took me a burned driver and three failed dimmers to understand a single sentence: the driver is the dimmer's conversation partner, not the lamp.

So, Can You Add a Dimmer Switch to Any Light?

No. That's the short answer.

The longer answer: it depends on the driver at every stage. If you've got line-voltage bulbs with their own dimmable drivers, a compatible wall dimmer usually works. If you've got a 24V system supplied by an external power source, the driver has to be dimmable — and it has to match the dimming method you choose. The fixture itself is almost irrelevant to the question.

Since that project, I've kept a pre-check list that I run on anything involving a dimmer. The first three items are always:

  1. Is the driver or power supply dimmable? Check the model against the datasheet. "Dimmable" is a spec, not an assumption.
  2. Which dimming method does it support — phase-cut, 0-10V, PWM, or resistance? Match the wall dimmer to the driver, not to the fixture or the lamp.
  3. What's the actual measured load? Spec for the number you measure. Buying a bigger power supply doesn't solve a dimming compatibility problem.

Granted, this fix worked because the chandelier was the only load on that driver. If you're mixing dimmable and non-dimmable sections in the same fixture, or using a sputnik chandelier with integrated dimmable bulbs and a separate non-dimmable supply, the wiring gets more complex. I can only speak to the constant-voltage scenario we had — your mileage may vary.

The LRS-240-24 remains a perfectly good Mean Well 24V 10A power supply model — for systems that don't need dimming. The PWM-120-24 was the right Mean Well product for this job, and I'd have known that in five minutes if I'd made the call first. A 20-minute conversation with a proper distributor would've saved me $860 and six days of rework.

The lesson I keep repeating to new team members: five minutes of verification beats five days of correction. And when a client asks if you can add a dimmer switch to any light, the honest answer isn't "sure." It's "let me check the driver."