Evolving Electrical Testing Methods
Jun 10, 2017
I need to correct something I've advocated over the past few years, about how to test for voltage in the wiring systems on farm equipment. I've been a big fan of wire probes, wire piercers, and gadgets that allow me to poke a needle or pin through the insulation on wires to allow me to test the voltage on the wire inside.
A discussion with a Mac Tools salesman reminded me that my techniques and tools are somewhat out-of-date and contrary to the preferences of most equipment manufacturers. Because many of the electronics on modern farm equipment operate on much less than the standard 12 volts, those wires are very susceptible to ANY corrosion. So equipment manufacturers are really fussy about anything that creates even the possibility of moisture corroding wires. To minimize the risk of corroding wires, they prefer that we back-probe at wiring connectors or plugs with small, long needles designed specifically for that purpose. Their theory is that back-probing through the rubber boot or isolator on harness connectors has less chance of damaging the waterproof nature of the plugs than poking holes in the hard plastic insulation on the wires.
So I'm going to have to buy a set of back-probes, because that's probably the right way to do things. But till then, I guess I'll have to keep piercing wires with my little needles, and then dabbing the teeny, tiny holes in the insulation with Liquid Tape or other sealant.
(And if you're still using your pocket knife to peel back some insulation on a wire so you can test it for voltage, then wrapping the sliced wire with electrician's tape-- I've seen the results of that technique. The only benefit to that technique is that I know exactly where to start looking for problems when I see patches of electrician's tape on a wiring system that has malfunctioned.)