I designed this enclosure for a small/cheap AC power meter (with power factor) I purchased for under $20 on Amazon:
"AC Power Meter, DROK Digital Multimeter AC 50-300V 20A Voltage Ammeter Amperage Volt Current Power Factor Energy Frequency Tester Amp Watt Power Gauge Monitor LCD Display" by Drok
The meter functions quite well from my brief testing with various devices against a fluke meter for amps, volts, and frequency. I have no way of verifying the power factor output, but it appears to be accurate enough for my needs (low pf for switching supplies, high for resistive loads, etc...). With the box and cables, this neat little PF energy meter fits in my toolbox next to my other hand meters. :)
To finish it, you will need:
1@ printed top and bottom parts
4x M3x10 (or longer) hex head bolts
Print the bottom with build-plate only supports, and the top with no supports. The Drok meter snaps firmly into the top with it's built in clips. The top and sides of the interior give enough room for solder joints, crimps, or even small wire nuts if you prefer. Both sides have built in strain reliefs, sized for 8mm diameter cables. You pick which side is in/out, and the length of wire leads you like. I chose a 3' input lead, and a 1' output for convenience in certain situations, with a 'left to right' convention. Add very tight zipties to the wires just inside the box, for better pullout protection. As you tighten the bolts, the 'pipes' in the strain relief will grab the wires and prevent rotation. The box is designed with 3mm thick walls, for a robust tool... with slightly sarcastic naming. Finish it off by filling the text on the top with your favorite paint (or print the first 1mm layers in a contrasting color).