The measured values of high fields emitted by an arc from a standard Marx Generator indicate possible immunity problems for equipment which satisfied the EMC requirements. This is because there are no high field frequency pulse field tests in the IEC and, hence, no equipment would have been tested against this form of interference. Immunity Standards, such as the IEC 1000—4-4 [11], deals with conducted immunity to electrical fast transients bursts. This requires an EUT to be subjected to a burst of 5 us/50 us pulses, at selected levels of 0.5, 1, 2, 4 kV, on power supply lines.