EMC - EFT (Electrical Fast Transients) on SIP couples erroneously with other cable

[occounty]

Hi all,

One of the EMC tests is to perform EFT which is Electrical Fast Transients per 61000-4-4 on AC mains (if applicable) and on other cables connected to UUT.

Preferred method to perform EFT on cables is via capacitive coupling. Standard specifies to route other cables which are not under test as far as possible to avoid coupling.

We are experiencing this issue that while performing EFT on one of cables the EFT test voltage gets coupled to other cable(which is not under test) and the test fails (monitored parameters mal function).

The erroneous coupling is verified by the fact that the mal functioning goes away when other effected cable is wrapped in copper foil and EFT test performed in the same manner as earlier.

Is there any way we can decouple/isolate/insulate the cable (which is not under test)?

Or is there any other way we can couple the test voltage to cable under test other than capacitive clamp to see if that would make a difference?

Would appreciate your help!!
Thank you.

 

[Jaydub]

Assuming this is related to your other question and this is a medical device, IEC 60601-1-2 requires capacitive coupling for SIP/SOP.

I don't know of any provision for isolating the cables not under test, other than cable routing.
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