This goes for the test probes being used as well.ĭo not use a meter/probes rated less than the voltage of the equipment being tested. There are two major factors in choosing the correct meter for the job, voltage level and category rating. Solution: Choosing the correct meter and probes The bottom line is to ensure you have the proper category meter for the job. If you want to get a better understanding of these categories, here is a great article from Fluke. The transient voltage will travel through the utility connection into the facility's three-phase power distribution, down to the single-phase circuits, and eventually to the electronics in the offices.Īs the spike works its way through the system it is being continually reduced until it becomes negligible.Įach multimeter category is based on the amount of power available at each of these locations.
Imagine lighting strikes the transmission lines outside of a factory. This is why it’s so important to make sure you have purchased a digital multimeter with the proper category rating for the work you are performing. Lighting strikes on outdoor transmission lines is also a highly probable cause for a voltage transient. Often, within a plant, these overvoltages can be generated by motors, capacitors, and variable speed drives. Occasionally the voltage on a 480-volt system can find itself all the way up to 8000-10,000 volts! Voltage transients are just a fancy term for voltage spikes. Let’s look at some of the possibilities that are out there and what we might do to ensure they don’t happen to us or the people we work with. Shock hazards can occur if the meter and test leads are not properly maintained.Īrc flash can occur if the meter is not properly rated for the voltage, the meter is exposed to transient voltages outside of its operating conditions, or because of defective parts or components.
Many electrical incidents have occurred while qualified electrical workers were using a digital multimeter or test instrument. There have been a number of cases over the years where something has gone wrong during the testing phase and someone has been exposed to a serious arc flash event or shocked. Think about it, in order to complete the test, an electrician has to come within inches of potentially energized circuits parts, and touch those circuits parts with two probes that are about the size of a pen… that doesn’t make me very comfortable. What most people don’t realize is when electricians are performing that ever crucial step of determining the absence of voltage they are actually at an increased level of risk of causing an arc flash or getting a shock. What are the dangers of digital multimeters? More importantly, they offer a reliable means to determine the absence of voltage, which is an electrician’s most critical step to ensuring their safety. They offer a wide range of functionality and allow you to determine what’s going on in your electrical system very quickly. Digital multimeters are one of the most important components of an electrician’s tool kit.