Checking the fuse is an indispensable step to verify the safety of electricity use. In household electricity use, the integrity of the fuse is related to the safety of life, which should not be ignored. Before we test whether the fuse is blown, we need to have a multimeter.Of course, most of the multimeters on the market are digital, and we also recommend choosing a digital multimeter when testing, which will greatly reduce your workload. If you need to know the multimeter correctly, please refer to the article “https://mestekinstruments.com/learn-to-use-a-multimeter-in-one-minute-a-beginners-guide/”.
How to quickly detect whether a fuse is good or bad?
Observe the inside of the fuse directly. If you see the metal wire is broken, burnt or melted, it means the fuse is damaged. If the fuse shell is ceramic and you cannot see the internal situation, you must use a multimeter to test it.When you are done, please remember to turn off your multimeter. When replacing a fuse, make sure it is blown, and choose a good quality fuse.
When we test, insert the black test pen into the COM (common terminal) of the digital multimeter, and insert the red test pen into VΩmA (10A port is only used to measure large current, generally not used for fuse testing).We touch the two test pens to the two ends of the fuse (the metal terminal part of the fuse) and read the resistance value displayed on the LCD screen. If the display is close to 0Ω (such as 0.2Ω-2Ω), it means that the fuse is intact, and if it displays “OL” or a high resistance value (MΩ level), it means that the fuse has blown.
NOTE: If the fuse still has continuity between the terminals after the circuit is broken, you should do a second test. I have seen fuses that are only partially blown and still have continuity, but after the circuit is closed, their resistance is high and the voltage drops.
When we test the fuse, the dial numbers of the digital multimeter we use look a bit complicated. At this time, you can choose an automatic or smart multimeter. They have a beep warning sound for on/off, which makes it easier to find the fault status during testing.
Ensure safe work
Before testing the fuse’s blown state, please make sure you have done the following:
(1) The multimeter and test pen should be used together, which is in compliance with safety standards. (Do not use a damaged test pen)
(2) When the multimeter is not adjusted to the function being measured, do not let the test pen touch the circuit being tested
(3) Do not touch the metal end of the test pen with your hand during the measurement process
(4) The fuse must be disconnected from the circuit for measurement, otherwise it may be affected by other components (the safest way is to wear protective gloves to remove the fuse)
(5) Proceed under the premise of ensuring your own safety. This is a very important piece of advice
