Here's the opinion I give most new techs, whether they ask for it or not: if you already own a decent multimeter, your next serious purchase should not be a better multimeter. It should be a thermal camera. If you maintain motors and feeders, an insulation tester belongs high on that list too. I know this sounds like the opposite of the usual tool-buying advice. I learned it the expensive way.
I've been doing industrial electrical maintenance and thermal imaging inspections for about seven years. I've personally made—and documented—11 significant tool and inspection mistakes, totaling roughly $4,800 in wasted budget. Now I maintain our team's pre-inspection checklist, so newer techs don't repeat the same errors. Nothing in this article is theory.
A better multimeter won't find what you aren't testing
In my first year (2017), I made the classic beginner mistake: a motor feeder kept overheating, so I bought a more accurate multimeter, as if more decimal places would reveal where the heat was coming from. It didn't. Voltage looked balanced. Current looked normal. The problem was a loose connection that only misbehaved under load, and by the time it tripped the breaker, we had already lost production.
I'm not knocking the meters I used then or now. An 88V multimeter is a genuinely capable tool, and I tell technicians who own one to keep it. But a multimeter answers questions you already know to ask. It can't show you which of the fifty terminations in a panel is about to fail.
A thermal scan can. In September 2022, I watched a senior electrician chase an intermittent VFD trip for three hours, swapping sensors and testing everything in sight. When I finally pulled the FLIR TG267 out of the truck, one image showed the output lug on L2 running roughly 55°C above its neighbors. Give or take, since I did not record the ambient temperature that day. Tightening the lug fixed it in about twenty minutes.
Most FLIR TG267 thermal camera reviews focus on sensor resolution or temperature accuracy, and those are fair things to evaluate. But the practical value I keep seeing is the speed of moving from something is wrong somewhere to that connection, right there. A multimeter can't do that.
Megger vs insulation tester: words get in the way
The other tool I underestimated for years was an insulation tester. Technicians ask about the megger vs insulation tester distinction all the time. The short answer: megger started as a brand name and over decades became a generic way to say insulation test. Some people say they megged a motor even when the tester on the truck is not that brand. That's fine. What concerns me is when someone expects a multimeter to do the same job.
A multimeter's resistance mode uses a low internal voltage, which is fine for continuity checks. It is not enough to reveal insulation that breaks down under stress. A real insulation tester applies 500 V or 1,000 V for a short period and measures leakage under that pressure. In 2021, I checked a 480 V pump motor with a multimeter and saw about 2 MΩ from winding to ground. I called it acceptable. A few weeks later, the motor tripped a ground fault during startup and the stator was cooked. When I tested the same winding with an insulation tester at 500 V, it read about 0.3 MΩ, well below the 1 MΩ floor that most maintenance guidelines use for motors rated under 1,000 V.
That replacement cost roughly $3,200 plus a week of downtime. The insulation test would have taken ten minutes. This is why I now put an insulation tester on the same priority list as a thermal camera: it turns a predictable failure into a scheduled repair.
The efficiency win is often in the workflow, not the sensor
The part that surprised me was where the efficiency came from. I assumed a higher-end camera with better resolution would always save the day. In practice, the tool that improved our inspection habit the most was a FLIR USB thermal camera that plugged into a phone. The image was not as refined as a professional unit, but in a panel scan you are not looking for a pretty picture; you are looking for a temperature pattern that stands out. The phone workflow made the difference: photos stayed on the phone, notes were added in seconds, and reports were finished in the parking lot instead of days later.
I should add that a phone camera isn't the answer for every job. In rough weather or awkward spaces, I prefer the TG267 because it is one-handed and there is no phone to juggle. The broader point is that the best inspection tool is the one your crew will actually use. A camera that stays in the truck because it is annoying to use has no return on investment.
I don't have hard data on how many failures this habit has prevented across the industry. I can only speak for our logs: in the past 18 months, we have recorded 47 reportable anomalies. Some were minor. Four of them were real faults already developing—one motor winding, one fuse clip, two breaker connections. Those are the exact faults that used to reach us as unplanned downtime.
What if you cannot buy everything at once?
That is the objection I hear most, and it is fair. Not every shop can fund a full thermal program overnight. But the answer is not to keep buying slightly better multimeters and hoping for the best. A practical order looks like this: start with an entry-level FLIR USB thermal camera so the habit actually begins; add a real insulation tester next; then move up to a rugged handheld like the TG267 if the site justifies it. Keep the multimeter through all of it. It still confirms voltage, measures load, checks continuity, and does the jobs that scanning tools cannot.
One more tool deserves a mention: a metal detector. It sounds trivial next to a thermal camera, but if your job includes mounting sensors, brackets, or junction boxes, thirty seconds with a metal detector before you drill can keep you out of an embedded conduit. I learned that in 2019 after mounting a sensor with a screw that landed exactly in an EMT conduit. Let's just say the repair cost more than the sensor. A thermal camera cannot see through drywall, and a multimeter cannot unscrew a mistake. Use the boring tool first.
I am also not suggesting that thermal imaging replaces safe electrical work practices. If you scan live equipment, do it as a qualified person under a documented safety program; NFPA 70E is the benchmark I know. And for occasional home use, a basic multimeter is probably all you need. My argument is aimed at people who are paid to keep equipment running. In that world, downtime is the real cost, and efficiency is the whole game.
To be clear, I don't think every thermal image will uncover an emergency. Most scans are normal, and that is fine. But when I look back at the $4,800 worth of mistakes that shaped our checklist, the biggest lesson is simple: a more precise meter only helps you measure the points you guessed in advance. Thermal imaging and insulation testing help you find the ones you didn't. If I could redo my buying decisions from 2017, I would have bought the scanning layer first. The meter was never the real bottleneck.
