What is the correct connection method for the LISN in the edge box conducted interference test?

For conducted emissions testing of edge computing boxes, a Line Impedance Stabilized Network (LISN) is used. The LISN is connected in series between the power supply and the EUT according to CISPR 16-1-2 standards. The power supply terminal is connected to the LISN input, and the EUT to the LISN output. The LISN RF output port is connected to the receiver (50Ω), and its ground wire must be connected to a low-impedance reference ground plane. The edge box's 24V DC power supply positive and negative are connected to the LISN positive and negative respectively. Common-mode interference testing requires simultaneous measurement of both the + and - lines to the reference ground. The results are taken as peak and average values, with limits determined according to product classification. Before testing, the LISN must be calibrated under no-load, and the EUT must operate in typical mode. A pre-installed common-mode filter (CMZ3225A-501T) in the edge box design can reduce LISN measurements; verification shows that after installation, conducted emissions at 0.3MHz decreased by 15dB.