When the measurement is complete, the clamp meter's changeover switch should be placed at the maximum range. Generally speaking, the clamp meter has a digital display and a pointer display, when measuring approximately the approximate range of the measured current, pay attention to the choice of the clamp meter range, and try to choose the right content to reduce the error. In addition, try to clamp the wire in the middle of the jaws of the clamp meter, if the measured current is too small, you can wind the wire into more than one, and then the measured value divided by the number of roots, but also note that you can not measure the bare wire, to avoid the risk of electric shock. If it is a clamp meter that can measure voltage and other functions, the pencil should be removed when the current is measured. Further, in a three-phase load, the clamp's jaws measure the current of the line, and the clamp of two measures the current of the third.