Effects of DC cable routing in immunity testing

The main objective of the International Electro technical Commission (IEC) immunity series testing is to establish a common and reproducible basis for evaluating the performance of electrical and electronic equipment when subjected to electromagnetic disturbances. Even though IEC immunity standards do mention about power cables, they primarily refer to the alternating current (AC) cable. There is no defined routing specified for the direct current (DC) cable. For typical electrical and electronic products which are powered through an external power adapter, the length of the DC cable may range somewhere between 1.5 and 2 meters. Repeatability and reproducibility are a challenge if this length of DC cable is not routed consistently. This paper highlights the importance of consistent cable routing when performing immunity series of testing. This paper also addresses how the performance of the product varies with different cable routing configurations. The immunity series considered for this paper encompasses electrical fast transient (EFT) test, conducted radio frequency (RF) field test, and radiated RF field test