Document: NRC Regulatory Guide
Document ID: 82021804-a487-471b-a76c-095315525b53
Document Type: regulatory_guide
Title: Guidelines for Evaluating Electromagnetic and Radio-Frequency Interference in Safety-Related Instrumentation and Control Systems (Rev. 2)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML1628/ML16281A531.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.180
CFR Part: 
CFR Title: 

Content:
dge of the waveform intersects the V=0 line for the open-circuit voltage and the i=0 line for the short-circuit current. The peak value of the open-circuit voltage of the Combination Wave and the peak value of the short-circuit current are given in Table 23. For the IEC test, the withstand levels correspond to Level 3 and Level 4 for the low and elevated surge conditions, respectively. During the performance of the test, the equipment under test should not exhibit any malfunction or degradation of performance beyond specified operational tolerances when subjected to the Combination Wave. Acceptable performance of the equipment under test should be defined in the test plan by the end user or testing organization according to the applicable equipment, subsystem, or system specifications. Figure 5.2 Combination Wave, Open-Circuit Voltage DG-1333, Page 29 Figure 5.3 Combination Wave, Short-Circuit Current 5.3 IEEE Std. C62.41 Electrically Fast Transients and IEC 61000-4-4 The EFT waveform consists of repetitive bursts, with each burst containing individual unidirectional pulses, and is intended to represent local load switching on the ac power leads of equipment and subsystems. The individual EFT pulses have a 5-ns rise time and a duration (width at half- maximum) of 50 ns. Plots of the EFT pulse waveform and the pattern of the EFT bursts are shown in Figures 5.4 and 5.5. The number of pulses in a burst is determined by the pulse frequency. For peaks less than or equal to 2 kV, the pulse frequency will be 5 kHz±1 kHz. For peaks greater than 2 kV, the pulse frequency will be 2.5 kHz±0.5 kHz. The rise time is the time difference between the 10% and 90% amplitude points on the leading edge of the waveform. The duration is the time between the 50% amplitude points on the leading and trailing edges of each individual pulse. Individual pulses occur in bursts of 15 ms duration. The peak value of the individual EFT pulses is given in Table 23. For the IEC test, the withstand