Our technician, Sam, sauntered into my office this afternoon like techs often do on a slow spring afternoon before the summer hits. It's been a long day for me, lots of training prep, a bunch of little fires, and errands to stomp out, and I still didn't get my article for the day written. I […]

On an energized, intact circuit, you will read voltage across an OPEN switch when testing with a voltmeter. However, you probably won't read significant voltage across a CLOSED switch. Both sides of a closed switch are electrically identical (or at least very close). Therefore, there should be no movement of electrons between the leads of […]

One of the most common questions we get from techs is about using a voltmeter to diagnose a high voltage circuit. It's especially tricky when a tech is used to working on a low-voltage or 120V circuit, where there is a clear “hot” side of the circuit and a clear “grounded” side of the circuit. […]