A non-contact volt/ammeter is more than adequate for most general servicing jobs.

A non-contact volt/ammeter. Photo courtesy of Jim Wheeler.

Something that I learned in a previous life as a supervisor over electronic technicians in a TV manufacturing plant (back in the 1960s) is that engineers don’t usually make good technicians. Engineers are specialists, while good technicians are generalists with knowledge covering a broad range of fields.

Good candidates for HVACR service techs must not only understand thermodynamics and airflow, but they also need to be pretty good plumbers and electricians, since much of the service work in our industry has to do with electrical problems and proper disposal of water. So, in addition to refrigerant gauges, vacuum gauges, airflow instruments, thermometers, etc., they also need some good and reliable instruments to measure electrical pressures, flows, and resistance.

Back when I made the jump from the field of electronics into HVACR, the main electrical meter that was used by my service techs and me was a clamp-on ammeter, which also had probes for reading voltage and resistance. They’re still around. While I was covering an AHR Expo in Chicago several years ago, I noted a new type of electrical measurement device at the Amprobe booth, so I stopped by to ask a few questions. What they had was something brand new at the time - a non-contact volt/ammeter.

Well, I was pretty skeptical, and my first reaction was to question the accuracy and practicality of this little “stick.” After all, there is no actual analog scale (just a line of LED indicators), and how accurate could the thing be without actually making physical contact? So I started to turn and move on to the next booth, when the product manager said, “Here, let me give you one. Try it yourself and see what you think.”

I don’t remember how many years that I’ve had it by now (it was a new product back then), but this has become my favorite electrical instrument, because it is so easy to use and it is more than adequate for most general servicing jobs. For a few critical operations I would prefer a true-RMS volt/ammeter, and it doesn’t read ohms. However, I can, do, and have used it many times to find the source of electrical problems in everything from 24-volt thermostat circuits to 480-volt industrial jobs. It fits in my pocket and I don’t have to make contact with live electrical lines.

So, what’s my point? If your company isn’t stocking and selling huge numbers of these fine instruments, you should consider it. An online search reveals there is at least one other company (Fluke) that manufactures them.

 A good supply house doesn’t just sell parts and equipment that people come in and ask for. The good ones are proactive and looked to as a source of information and education. Customers recognize and appreciate those who teach.