I am part of a hobby project where we have a pair of fat, insulated #4 AWG stranded copper wires carrying +5V and ground. I want to tap into these wires every few inches to draw power off it (max draw of around 4A per tap), for a total of 24 tap pairs.
The 'best' idea I've had so far is sketchy: Drive some steel metal screws in through the insulation and into the center of the wire strands. Solder the connecting wires off of the heads of those screws, and eventually cover the heads in electrical tape or similar (to prevent people accidentally shorting across two posts).
How much electrical loss would you expect from this connection? I'd prefer it if these were copper screws instead of steel, but the local hardware store does not have those. Is the resistance of steel negligible given the short travel distance?
Do you have a better suggestion for tapping into this wire? The best 'correct' solution I've found for an insulation-piercing tap that will handle #4 AWG appears to cost $15 for each tap. Since I need 48 taps, this path would be prohibitively expensive.