What should be paid attention to when the clamp ammeter measures DC current
The test wire must first be inserted into the center of the wrench's jaws, which must then be tightly closed. Next, the wrench must be loosened. Jaws should be opened and shut again if there is noise on the joint surface. The joint surface should be treated to ensure the reading is correct if there is still noise. Also, avoid clamping two wires simultaneously. Open the jaws, remove the measured wire, and then adjust the gear to the highest current gear or OFF gear after reading.
Second, depending on the size of the detected current, it is required to choose the correct clamp ammeter range. The chosen range needs to be a little bit bigger than the measured current's value. If it cannot be estimated, start measuring at the maximum range and gradually shift gears until the range is appropriate. This will prevent damage to the clamp ammeter. Changing the clamp ammeter's gear position while taking measurements is strictly prohibited. Before shifting the gear position, the measured wire needs to be taken out of the jaws.
When conditions allow, the measured current-carrying wire can be wound numerous times and then placed into the jaw for measurement for measuring currents less than 5 amps in order to increase the reading's accuracy. At this point, the reading of the meter divided by the quantity of wire coils placed in the jaws should match the actual current value of the wire being tested.
Keep a safe space between every portion of the body and the charged body during measuring. The low-voltage system's safe operating range is 0.1 to 0.3 meters. When measuring the current of each phase of a high-voltage cable, the insulation must be good, the distance between the cable ends must be greater than 300mm, and the measurement can only be done when it is deemed convenient. Maintaining a secure space between the head and the live portion is especially important when examining the timing of the watch. Every portion of the human body should be kept at least as far away from a live body as the clamp meter's whole length.
It is important to safeguard and isolate the fusible fuses or busbars of each phase before measuring the current of low-voltage fusible fuses or horizontally placed low-voltage busbars in order to prevent interphase short circuits. Due to the poor insulation level of the cable head and potential risk to human safety, it is strictly prohibited to take any precautions when one phase of the cable is grounded.
