TABLE OF CONTENTS All the disturbances previously mentioned can sometimes occur on power lines as a result of local loading or switching problems rather than from external sources such as lightning. While the undesirable properties of equipments generating switch-off spikes and being susceptible to incoming transients are addressed in military standards, commercial equipment has in the past had to operate in the presence of similar disturbances but without the comprehensive immunity achieved by rigorous design in compliance with a set of standards.
Early studies by IBM (1974) showed that most power supply related problems with regard to computer equipment were due to the existence of transients on power cables. Other measurements by AT&T and the US Navy have deduced that voltage sags and dropouts were the primary causes of computer disruption. Taken together, this suggests that transient suppression and the provision of internal stored energy in the equipment are two necessary design features of modern digital electronic equipment.
The CS06 spike test in MIL STD 461/2 has been adopted as a good test for both military and commercial equipment.
Examples of other relevant standards include
ANSI/IEEE STD C62.41 (1980) formerly IEEE STD 587: Guide for surge voltages in low-voltage AC power circuits, essentially a lightning damage specification [64]. It defines surge/transient voltages and currents up to 6 kV and 3 kA. There are two classes of equipment: Class A, those connected further than 10 m...
