LED PSU Boot Sequencer

I learned about inrush current at Tracks. A large video wall I helped install kept tripping the breakers every time the room powered up, and it took a while to figure out that the power supplies were pulling a huge spike for a fraction of a second before settling down. I have read the inrush line on every spec sheet since.

So when I needed to run eighteen power supplies for the blackout ceiling tubes, I knew what to do. Pulling more electrical circuits cost too much. Instead I built three 3D-printed sequencer boxes to stagger the load. Six supplies per box. Inside, a small power supply runs a relay board as a switch bank. Packing high-voltage lines, relays, and a nest of WAGOs into a sealed case took a few printed revisions before everything fit. Every connection uses a locking connector. Indicator LEDs on the front show which outputs are live, and status lights on the back confirm AC power.

The boxes sit on the black wall just above the rafters. Flipping the main breaker starts a cascade of relay clicks across the room, and every five to ten seconds another section of ceiling wakes up as its capacitors charge. When the cascade finishes, the whole rig runs silent.