Cable Testing

James R. White, Shermco IndustriesColumns, Fall 2020 Columns, Tech Quiz

Cable testing is one of the oldest forms of testing in the industry. At first, cables were tested using DC voltages, but this was found to damage newer cable types, so additional cable testing methods were developed. This issue’s Tech Quiz takes a look at cable testing.

1. During the early years of cable testing, which two primary types of cable were in use?

a. Cross-link polyethylene (XLPE)

b. Ethylene-propylene rubber (EPR)

c. Paper-insulated lead-covered (PILC)

d. Polyethylene

2. ANSI/NETA MTS 2019 lists three AC test sources for diagnostic testing. What are they?

a. _____________________________

b. _____________________________

c. _____________________________

3. Which cable tests are not recommended after an extruded dielectric cable (XLPE, EPR) reaches service life (5 years)?

a. VLF — very-low frequency

b. Power factor — tan delta

c. DC high potential

d. Damped alternating current

4. The main advantage of testing at very-low frequency (VLF) is that it significantly reduces the size, weight, and cost of the required power supply and thus offers greater attraction for testing medium-voltage cables in the field.

a. True

b. False



James (Jim) R. White, Vice President of Training Services, has worked for Shermco Industries Inc. since 2001. He is a NFPA Certified Electrical Safety Compliance Professional and a NETA Level 4 Senior Technician. Jim is NETA’s principal member on NFPA Technical Committee NFPA 70E®, Electrical Safety in the Workplace®, NETA’s principal representative on National Electrical Code® Code-Making Panel (CMP) 13, and represents NETA on ASTM International Technical Committee F18, Electrical Protective Equipment for Workers. Jim is Shermco Industries’ principal member on NFPA Technical Committee for NFPA 70B, Recommended Practice for Electrical Equipment Maintenance and represents AWEA on the ANSI/ISEA Standard 203 Secondary Single-Use Flame Resistant Protective Clothing for Use Over Primary Flame Resistant Protective Clothing. An IEEE Senior Member, Jim received the IEEE/IAS/PCIC Electrical Safety Excellence Award in 2011 and NETA’s Outstanding Achievement Award in 2013. Jim was Chairman of the IEEE Electrical Safety Workshop in 2008 and is currently Vice-Chair for the IEEE IAS/PCIC Safety Subcommittee.