First off a PI test does not involve different voltages, it is a constant voltage test comparing the results at different time intervals (1 minute and 10 minutes)
Second, while we are on the topic, a megger is a brand name, like kleenex, that most people use to describe a Insulation Resistance test.
Thirdly, You can’t measure resistance
You are probably saying to yourself, “Are you nuts? I have an ohmmeter and a megometer in my truck that I use to measure resistance every day!” Well let’s get back to basics and review how an “Ohmmeter” works.
A megohmeter is actually measuring current. The meter applies a test voltage and measures the current flow through the circuit and uses Ohms law to calculate resistance which is displayed on the meter in Ohms. If the applied voltage is not high enough, the amount of current passed through the resistance is below the sensitivity range of the meter. I think that is what reno was trying to describe in his "micro tester" theory, but that sounds more like a microhmeter description to me, which is worthy of its own thread IMHO.
