Document: NRC Regulatory Guide
Document ID: 8e45dce1-e1e7-4415-b1dd-7e2a610e545b
Document Type: regulatory_guide
Title: Fire Protection for Nuclear Power Plants (Rev. 4)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML2023/ML20231A835.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.189
CFR Part: 
CFR Title: 

Content:
r <1,000 V AC 1,500 V DC1 None Instrument and Control <250 V DC <120 V AC 500 V DC None The review guidance for Megger and Hi-Pot test voltages was derived from Institute of Electrical and Electronics Engineers (IEEE) 383, “IEEE Standard for Type Test of Class IE Electric Cables, Field Splices, and Connections for Nuclear Power Generating Stations,” and IEEE 690-1984, “IEEE Standard for the Design and Installation of Cable Systems for Class 1E Circuits in Nuclear Power Generating Stations” (Ref. B-3). The electrical cable functionality tests recommended above are one acceptable method to assess degradation of cable functionality. The NRC staff will evaluate alternative methods on a case-by-case basis. The above table summarizes the “typical” Megger and Hi-Pot test voltages, and the applicant can follow the applicable industry standards and manufacturer’s recommendations for the specific cable application in the performance of the IR and Hi-Pot tests. B-3.3 Air Oven Tests Air oven tests can evaluate the functionality of cables for those cable tray or raceway fire barrier test specimens tested without cables. This testing method consists of exposing insulated wires and cables at rated voltage to elevated temperatures in a circulating air oven. The temperature profile for regulating the temperature in the air oven during this test is the temperature measured by the AWG 8 bare copper conductor during the fire exposure of cable tray or raceway test specimens tested without cables. The test method described by Underwriters Laboratories, Inc. (UL) Subject 1724, “Outline of Investigation for Fire Tests for Electrical Circuit Protective Systems” (Ref. B-4), Appendix B, 1 A Megger test voltage of 1,000 V DC is acceptable provided that a Hi-Pot test is performed after the Megger test for power cables rated at less than 1,000 V AC. DG-1359, Appendix B, Page B-8 “Qualification Test for Circuit Integrity of Insulated Electrical Wires and Cables in Electrical