How to correctly use the EFT test coupling clip for edge computing boxes?

For the IEC61000-4-4 Electrical Fast Transient/Bulk Test (EUT) of the edge computing box, capacitive coupling clips must be used at the signal ports. The coupling clips should cover the length of the cable under test (1m), with a coupling capacitance of 100-1000pF. Interference can accumulate on the cable. Proper usage includes:

1. Placing the coupling clip 0.5m from the EUT and as close to the EUT as possible.

2. Coiling any excess cable 0.1m from the reference grounding plate and away from the coupling clip.

3. Connecting the coupling clip's grounding strip to the low impedance of the reference grounding plate.

4. Gradually increasing the test voltage from low to high, not exceeding the product rating.

For edge box signal ports such as RS485, a TVS diode (ESDSM712) and a common-mode inductor (CML3225A-510T) should be added before testing to ensure effective protection.