The modern digital multimeter (DMM) is ubiquitous, partly because it’s so incredibly useful. Even an entry-level industrial DMM is valuable, though of course the higher-end models take that up a few notches.
But don’t let the fact that “everyone” has a DMM lull you into thinking you know how to use yours safely. Maybe you do, but are you sure?
Take this short quiz, which covers (only some of the) important safety considerations for using a DMM:
• Does your DMM meet the safety standards for the environment in which you’re using it? Do you merely think so, or do you know so? If the latter, how exactly do you know?
• Do you carefully examine all stickers, signs, and labels on the equipment to ensure your DMM is going to be connected to 480V instead of 13kV?
• Do you inspect your test leads for physical damage before making a measurement? Things do happen in between jobs. Inspect every time.
• Do you always connect and disconnect the meter one lead at a time? If not, you may some day expose yourself to a nasty arc flash event.
Beyond the safety aspects, also note the performance limitations of a DMM. For many tasks, it’s not the right piece of test equipment. The list of such tasks is actually quite long, but it includes items such as testing circuit breakers for contact resistance and testing feeder cables for insulation integrity.
Use your DMM safely, and don’t try to use it for testing it’s not suitable for.