Hi Brian I am forwarding this response by Chase EMC as they have been having problems axcessing this system! Hope it helps! Message: 1000-2-6 is simply trying to provide a repeatible method for radiated immunity testing at frequencies below 80MHz. Becasue of the problems associated with low frequency radiated immunity testing in semi-anechoic chambers the IEC developed this standard to simulate the induced voltage found on cables while exposed to a radiated RF field. As we all know the cables are typically the coupling mechanisim for most RF fields into the EUT. This type of conducted immunity testing has been going on in the military arena for several years via Mil-Std-461. 1) The EN 50082-1 or -2 requires this test to be performed on AC, DC inputs/outputs and I/O cables. The 3 meter clause only applies to I/O cables. This 3 meter rule comes from the wavelength of the frequencies being applied. If your standard PC parallel port interface cable is less than 3 meters than it would NOT qualify to be tested. 2) If the EUT only has an AC mains, the return path would be the stray capactance between the EUT chasis and the ground reference plane (GRP). The correct common mode current is developed because the EUT chasis is 10cm above the GRP, the I/O cables are 3-5 cm above the GRP and the CDN loop impedance is 150 (300)ohms. With this in mind, the RF unmodulated current should be 33mA or 66mA for 3 or 10 volts, respectively. 2b) We have used five CDN's as the rule of thumb. Meaning if your EUT configuration yields greater than five I/O cables we recomend the use of BCI or EM Clamp. We have found that ground loops can exsist with multiple CDN,s thereby creating a possible RF short circuit condition. 3) If no ground exsists with the EUT than do not add one, simply use a M-2 CDN (two line). 3) CDN-T2 Telephone CDN-S1 Shielded Cable CDN-M1 Chasis ground of cabinet enclosure or EUT 4) Yes the clamp can be used on shielded cables but great care must be taken so that you do not exceed the current limit of the standard. This is done by monitoring the unmodulated current with an additional current probe located between the clamp and the EUT. See section 7.3 of the standard. 5) Most EMC labs and consultants agree that CDN's should be used for AC mains unless the AC current exceeds 50-100 amps. But to answer your question, the clamp can be used to test AC mains provided you monitor the resultant current per section 7.3 of the standard. The 30cm strap you refered to is used for reducing the antenna effect of the clamp by grounding the shield of the coax. Please feel free to contact me directly to discuss this standard in more detail. CHASE EMC (973) 252-8001 Joe Heins Sr. EMC Application Engineer