It has been my philosophy is such cases, that a 3 meter length should be provided.
During radiated emissions and immunity tests, a minimum of 1 meter should be exposed. In the case of immunity, the 1 meter should be in the 'uniform' field area (even if you are not requiring the field uniformity test). The 3 meters then allows the cable to exit the enclosure. In the case of EFT, the standard specifies tests of cables >3 meters, and requires that the 1 meter coupling clamp be placed near the end of the cable. Using a 1 meter cable would be difficult because of the size of the clamp, and may also affect the results because of the potential for improved 'suppression' of the coupled transient via the support equipment. Bob Martin Sr. Technical Manager ITS - Northeast (978)263-2662 [email protected] The opinions expressed are my own and not necessarily those of my employer. ---------- From: Francis L. Fiedler To: [email protected] Subject: Cable lengths needed List-Post: [email protected] Date: Wednesday, April 15, 1998 6:24PM Greetings, Our equipment operates with cables that vary from two feet to two hundred feet in length. The length is dependent upon the customer's needs. Some cables are provided by the customer for their applications. We test our equipment to industrial environment using EN50081 and 50082. What length of cable do you think should be used for test purposes? The length of wire subjected to the test signal is usually one meter with additional 0.3 meters for positioning or decoupling purposes. Long length of wires can result in use of large areas and or bundling. Many test instructions specify not to bundle. All of your comments will be greatly appreciated. If you prefer to answer directly to me, your comments will be welcomed. Respectfully, Francis Fiedler
