- Author
-
Wyant, F. J.
|
Nowlen, S. P.
- Title
- Cable Insulation Resistance Measurements Made During Cable Fire Tests.
- Coporate
- Sandia National Laboratories, Albuquerque, NM
- Report
-
NUREG/CR-6776; SAND2002-0447P,
June 2002,
105 p.
- Distribution
- AVAILABLE FROM Government Printing Office, Washington, DC 20401-0003. Telephone: 202-512-1800. Fax: 202-512-2250. Website: http://www.bookstore.gpo.gov AVAILABLE FROM: National Technical Information Service (NTIS), Technology Administration, U.S. Department of Commerce, Springfield, VA 22161. Telephone: 1-800-553-6847 or 703-605-6000; Fax: 703-605-6900; Rush Service (Telephone Orders Only) 800-553-6847; Website: http://www.ntis.gov FOR MORE INFORMATION CONTACT: Nuclear Regulatory Commission's Public Electronic Reading Room Website: http://www.nrc.gov/reading-rm/doc-collection/nuregs
- Keywords
-
cables
|
fire tests
|
insulation
|
electrical cables
|
electrical faults
|
electrical insulation
|
failure modes
|
failure analysis
- Identifiers
- insulation resistance measurement techniques; Sandia National Laboratories insulation resistance measurement system; insulation resistance measurement results; current loop data and results
- Abstract
- An insulation resistance diagnostic system was recently developed and exercised during a series of cable fire tests sponsored by the commercial U.S. nuclear industry. This insulation resistance measurement system was able to iden- tify and quantify the changes in insulation resistance occurring between the separate conductors and the conductors to ground in cable bundles as they were being exposed to fires. Eighteen separate fire tests were conducted during the period January through May 2001 and included a variety of cable and fire exposure conditions. The insulation resistance measurement system was operated at a 120 V AC input to the conductors for 14 of those test runs and at 100 VDC input for three of the runs. One test was run with the insulation resistance measurement system providing 24 VDC to two separate instrument cables being exposed to the fire. The results obtained by the insulation resis- tance measurement system during these tests showed that cables will fail during a fire in one of three ways: by inter- nal shorting of the conductors in a multiconductor cable, by shorting of the conductors in different cables bundled together, or by individual conductors shorting to ground. No incidents of fire-induced open circuits were found to have occurred during any of these tests. A mockup of a simple 4 to 20 mA DC current loop instrument circuit was included in six of the later tests. The intent was to investigate the potential of misleading or loss of instrument indi- cation from fire damage to the signal cable. This report provides an analysis of the insulation resistance data and current loop results for the 18 tests run in the industry test program.