Before conducting any tests with a multimeter, you need to take some precautionary measures because you’re dealing with a potentially fatal source.
Follow these steps before performing a measurement:
- Discharge the circuit completely before using a multimeter
- Never apply power to the circuit when you measure resistance
- Before measuring AC, make sure you’ve set the multimeter on AC mode
- Make sure to connect the leads to the proper polarity while measuring DC
- If your multimeter doesn’t have an auto shut off function, turn it off manually after measuring and testing. Slide the switch to the “OFF” position. If the unit doesn’t have an “OFF” position, turn it to the highest AC spot
- Start with the highest voltage or current.
- Make sure that you’re reading AC measurements on the AC scale
- Avoid extension cords
- If you’re inspecting wires, check if they are properly insulated
- Don’t overload mA ranges past fuse capability