Document: NUREG-0800
Document ID: 1add33e8-ea1c-46d8-9e11-29944f57ca8a
Document Type: srp
Title: Revision 6 – August 2016
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML1601/ML16019A184.pdf
Revision Date: 2023-06
Chapter: 7
Section ID: 7
CFR Part: 
CFR Title: 

Content:
The specified MCF should equal or exceed the application requirements. RG 1.75 suggests that the MCF include the levels and duration of the fault current on the non-safety side of the device. American National Standards Institute (ANSI) Std C84.1-1989, Table 1, “Standard Nominal System Voltages and Voltage Ranges,” provides an acceptable basis for identifying nominal voltages and guidelines for steady-state tolerances. The device design should accommodate the fault voltage and current waveforms and characteristics defined for the application. Appropriate industry standards should be used as a basis for establishing the fault-transient exposure level (e.g., IEEE Std C62.41.1-2002, IEEE Std C62.41.2-2002). The physical arrangement of components in the isolation device should be configured to prevent, in the event of failure, the effects of shattered parts or material (e.g., solder spatter), fire, and smoke from breaching the isolation barrier. Description of Test Method A description of the specific testing performed for each type of isolation device should be provided. This should include elementary or schematic diagrams as necessary to describe the test configuration and how the MCF and surges will be applied to the devices during the test. The basis for the set of postulated electrical faults and failures should be included in the test program. A specific definition of pass/fail acceptance criteria for each type of device should be provided. This should include justification that the pass/fail acceptance criterion is sufficient to demonstrate that the tested device meets the requirements of IEEE Std 603-1991, Clause 5.6, or IEEE Std 279-1971, Clause 4.7.2. RG 1.75 recommends that the following: • The maximum credible voltage or current transient applied to the device output should not degrade below an acceptable level the operation of the circuit connected to the device input. • Shorts, grounds, or open circuits occurring in the output will not degrade