The Branches Chandelier That Wouldn't Stop Glowing

I wasn't planning to spend a Thursday morning in a dusty ceiling plenum, but that is what happens when a custom Branches Chandelier starts glowing after the wall switch is off and the installer on-site is already convinced the Mean Well LED driver is bad. The client noticed it first: the room lights were off, the rest of the lighting was off, and the warm-white branches still had a faint glow. Not one Hue spotlight in the same room did that. That was our first clue.

For context, I'm the quality/compliance manager at an architectural lighting manufacturer. I review every fixture and driver configuration before it goes out the door. In 2024, I signed off on roughly 200 unique configurations and rejected about 7% of the first samples for things like wrong output current, poor dimming behavior, or missing labels. I mention that because I've learned to ask which part is actually telling the truth. In this case, the Mean Well driver was probably fine.

The Branches Chandelier was powered by a remote Mean Well LPC-60-700 LED driver. It worked for two weeks. Then the customer started seeing the ghost glow late at night. The installer replaced the Mean Well led driver with a brand new one, and the glow stayed. He then took the original driver back to the shop, wired it to a test LED module, and it worked perfectly. That should have told us not to order a third driver.

Mean Well Power Supply Troubleshooting Has to Start Before the Driver

When I arrived, my first question wasn't about Mean Well driver specs. It was about how the switch was connected. Too often, a Mean Well power supply troubleshooting call turns out to be an installation wiring issue. The power supply is the part that reports the symptom, but the wiring is the part that causes it.

I opened the wall switch box and saw the problem immediately. The black feed from the breaker was connected directly to the cable running up to the driver. The white neutral wire went through the switch. So the switch was interrupting the neutral return path, not the hot feed. That is a code violation and a shock hazard, and it's also the kind of mistake that shows up with LED drivers more than it ever did with old bulbs.

Here is why: with the neutral switched, the Mean Well driver still had line voltage on its L terminal whenever the breaker was on. The switch only opened the return path. The driver was never fully disconnected from the source. With a high-efficiency LED load, even a tiny bit of leakage can be enough to make the LEDs glow or behave strangely. It's not really a driver failure. It's a circuit that never truly turns off.

How to Connect a Light Switch to a Mean Well LED Driver

The fix was straightforward, and it didn't require replacing the Mean Well led drivers. For a standard single-pole switch, the correct wiring path is simple: hot from the panel goes to the switch; the switch output goes to the L terminal on the Mean Well driver; the neutral wire goes directly to the N terminal; and ground connects to the switch and the driver case. The switch has one job: interrupt the hot conductor. It should never be installed on the neutral side, and it should never be wired between the driver and the LED load.

Put another way: the wall switch kills the AC feed to the driver. It doesn't control the low-voltage output, and it shouldn't be wired into the dimming leads. If the driver has DIM+ and DIM- leads, those are control wires. A wall switch is still an AC line-side device. I tell people the same thing every time: if you remember how to connect a light switch to an LED driver, remember to switch the line side.

The Hue spotlights in the same room were not involved. They had their own power supplies and their own control system. A Hue spotlight can do clever things through its app, but it doesn't send current through a Branches Chandelier driver. The client thought the smart-home system was causing the glow. It wasn't. The switch wiring was causing it.

After we rewired the switch correctly, the Branches Chandelier stopped glowing. It's been running on the same Mean Well driver since then. No third driver was needed. The repair took about forty-five minutes, and the only parts used were a wire nut and a short pigtail.

Mean Well Power Supply Troubleshooting: The Checklist I Use

When I get a call about a driver that seems dead or won't turn off completely, I don't tell the installer to replace the driver first. I ask for four simple readings:

  • With the switch on, measure voltage between L and N at the driver terminals. If it matches the driver label, the input side is present.
  • With the switch off, check L to ground. If you still see line voltage, the switch is not breaking the hot conductor.
  • Disconnect the LED load and test the driver on a bench with a known good LED module. That separates a real driver problem from a load or wiring problem.
  • If the driver has dimming leads, don't use them as switch wires. Those leads carry a low-voltage control signal, not the AC input.

This is a Mean Well power supply troubleshooting checklist from real field experience, not from a datasheet. The datasheet will tell you the output current and terminal layout. It won't tell you that someone connected the neutral to the switch leg.

Do I Still Trust Mean Well LED Drivers?

Honestly, yes. Mean Well LED drivers are not magical and they can fail like any electronic component. But in this Branches Chandelier case, the driver was doing exactly what it should have done. The failed component was the wiring concept. The easiest way to reduce callbacks is to check the switch before you blame the power supply. Quality starts at the switch, and that's true no matter which brand of driver is mounted above the ceiling.