Precautions for clamp Ammeter when measuring current
Firstly, when using, the wrench should be tightened to open the jaws. Place the measured wire in the center of the jaws, then loosen the wrench and close the jaws tightly. If there is any noise on the joint surface of the pliers, it should be reopened and closed again. If there is still noise, the joint surface should be treated to ensure accurate readings. Additionally, it is not allowed to clamp two wires simultaneously. After reading, open the jaws, exit the measured wire, and set the gear to the highest current or OFF gear.
Secondly, select the appropriate range of clamp type Ammeter according to the measured current. The selected range should be slightly larger than the measured current value. If it cannot be estimated, to prevent damage to the clamp Ammeter, the measurement should start from the maximum range and gradually change the gear until the range is appropriate. It is strictly prohibited to switch the gear of clamp Ammeter during the measurement. When shifting, the measured wire shall be withdrawn from the jaw before changing the gear.
When measuring currents below 5 amperes, in order to make the reading more accurate, if conditions permit, the measured current carrying wire can be wound several times and placed in a clamp for measurement. At this point, the actual current value of the measured wire should be equal to the reading value of the instrument divided by the number of wire turns placed in the clamp.
When measuring, attention should be paid to maintaining a safe distance between all parts of the body and the charged body. The safe distance for low-voltage systems is 0.1-0.3 meters. When measuring the current of each phase of high-voltage cables, the distance between the cable heads should be at least 300 millimeters, and the insulation should be good. Only when the measurement is considered convenient can it be carried out. When observing the timing of the watch, special attention should be paid to maintaining a safe distance between the head and the charged part. The distance between any part of the human body and the charged part should not be less than the entire length of the clamp watch.
When measuring the current of low-voltage fusible fuses or horizontally arranged low-voltage busbars, each phase of fusible fuses or busbars should be protected and isolated with insulation materials before measurement to avoid causing phase to phase short circuits. When one phase of the cable is grounded, it is strictly prohibited to measure to prevent ground breakdown and explosion caused by low insulation level of the cable head, which may endanger personal safety.
