A better fuse block

As part of revamping i3′s front-door wiring, I needed to distribute several circuits of overcurrent-protected DC power. First, I grabbed an old bakelite fuse-block:


(Side note: Are you as sick as I am of trying to read the markings on a blown glass fuse? A little Sharpie solves that!)

This left two unsolved problems, though: Gathering all the return leads, and replacing fuses if I shorted something while wiring. I decided to make a little power distribution block, instead:


The yellow discs are a 900mA Polyfuse and two 2.5A Polyfuses. The LEDs (and 1k resistors) don’t see voltage until the associated Polyfuse “trips”, so they indicate a faulted circuit. That allows me to commit stupidity while wiring things up, know about it, and not spend a glass fuse each time. It was also trivial to add extra screw terminals and a return bus, solving the other problem.

The next trick was mounting the thing without shorting out the traces on the bottom. It turned out to be easiest just to stand off a second piece of perfboard below it. These boards are so cheap ($0.39 ea?) it wasn’t worthwhile to make a dummy panel out of some other material.


Then a little Dual-Lock for mounting, and it’s done…