Safety When Using Digital Multimeters
To prevent the possibility of electric shock or injuries, never measure an in-circuit current when the open-circuit potential to earth is greater than 1000V. If the fuse blows during this type of measurement, the meter can easily be damaged and you have an extremely high risk of injury. It is imperative to check the meter’s fuses prior to measuring current and never to place the probes parallel to any circuit or component. Always use the correct function, range and terminals for all measurements. Remember, no tool by itself can guarantee absolute safety. The combination of the right tool and safe work practices will give you maximum protection.
Use the following guidelines to increase safety when using a digital multimeter:
* Work on de-energized circuits when possible, also being careful to use lock-out/tag-out procedures. Always assume the circuite is live.
* Use insulated tools, wear safety glasses or a face shield and insulated gloves.
* Wear flame resistant clothing, and stand on an insulated mat.
* When making measurements on live circuits, hook on the ground clip first, then make contact with the hot lead. Hang or rest the meter when possible versus holding it in your hands.
* Use the three point test method; test a known live circuit, then the target circuit and finally test the target circuit again. This technique double checks that the meter worked properly before and after the measurement.