Back in March of 1990, I ran a test for field technicians in OSP magazine. There are many new techs out there and many new technologies so I’m going to run it again. This is a test for the new technician in the Triple Play business using that Last Mile of copper.

I’ve put together the following trivia questions on cable fault locating. The questions aren’t in any particular order, nor is any individual answer essential to success in the field. This is just a general gathering of a little information I feel the complete technician should have available in the field. I don’t expect that such things as feet-to-ohms conversions, feet-per-degree-of-temperature-change or gauge conversion charts be memorized, but such information should be at hand, in the field, when needed.

Here we go:
1. The manufactured capacitance characteristics of an exchange cable pair can vary from:
A. .076 micro-farads per mile to .090 micro-farads per mile
B. .030 micro-farads per mile to .064 micro-farads per mile
C. .045 micro-farads per mile to .087 micro-farads per mile
D. Does not vary

2. The varying twist length of adjacent pairs in a telephone cable controls:
A. Cross-talk
B. Elongation
C. Dielectric strength

3. When testing faulted pairs tip-to-ring in a wet pulp cable with no voltage present, a VOM will show a short from:
A. 20,000 ohms to about 500,000 ohms
B. 2,000 ohms to about 50,000 ohms
C. 200 ohms to about 5,000 ohms

4. When testing pairs in wet air core PIC, the VOM will show crossed battery on:
A. The ring conductors
B. The shield
C. Both

5. When converting an ohms measurement to sheath footage, the technician must account for:
A. Gauge
B. Temperature
C. Wire composition
D. Helical cable design
E. All the above

6. When using a portable resistance bridge, a separate good pair strung along the ground must:
A. Follow the exact cable route
B. Be the same gauge and temperature
C. Be a larger gauge
D. Be strapped to the faulted conductor at the far end

7. A resistance bridge measures all wire in a test section, including any laterals.
   (True)     (False)

8. A gauge change will not affect resistance measurements.
   (True)     (False)

9. An open meter measures all wire, including any laterals.
   (True)     (False)

10. The effect of induced AC on an unbalanced pair is:
A. Rings, can’t answer
B. No dial tone
C. Noise

11. When measuring the distance to an open with an open meter, and tip-and-ring open measurements differ, the correct distance is the:
A. Shorter
B. Average between the 2 measurements
C. Longer

12. A Time Domain Reflectometer (TDR) accurately measures splits as long as:
A. There are at least 12 working pairs in the test cable
B. There are no loads in the test section
C. There are no laterals in the section

13. When conductor- or shield-to-earth fault locating with a sheath fault locator, an earth gradient appears at:
A. Test set ground
B. Conductor-to-earth faults
C. Shield-to-earth faults
D. All the above

14. A field technician is fault locating in a 700-foot section of air core PIC cable. There are no other accesses. After he sets the proper gauge and conductor temperature, his resistance bridge measures 500 feet Distance-to-Strap. After removing the strap, his open meter, set to the proper capacitance of the cable, sees 700 feet. Marvin decides the test sets don’t work. What do you think is going on?
A. Water in the section
B. An unknown load coil in the section
C. Gauge change (cut cable and another gauge used to restore service)
D. Slack loop (left over cable buried by line crew or contractor)

15. The minimum acceptable loop current for an exchange cable pair, measured at the protector with a transmission test set, is:
A. 14 mA
B. 23 mA
C. 40 mA

16. Maximum acceptable station ground resistance is:
A. 45 ohms
B. 10 ohms
C. 25 ohms

17. When testing the subscriber’s pair at the protector with a transmission test set, Noise Metallic (NM) is unacceptable and Power Influence (PI) is acceptable, suspect:
A. Series resistance on the pair
B. One side open on a lateral
C. One side open beyond the subscriber
D. Crossed with a nonworking conductor
E. Any the above

18. The amplitude of a telephone signal is attenuated by:
A. Gauge changes
B. Load coils
C. Bonding
D. Capacitance

19. Marvin is chasing resistive trouble in aerial plant in the hot sun. He measures Strap-to-Fault as 1,500 feet of 24-gauge at 110 degrees. His map shows the aerial goes buried 750 feet away. At the point where the cable goes buried, the map shows a gauge change to 2,700 feet of 22-gauge. The underground temperature is 84 degrees. Marvin decides it’s either cut-to-clear or make an illegal “repairman’s access” at the pole. But he has all the information needed to go straight to the fault. What is the actual STF footage to the fault when measured with a tape measure or an engineering wheel?

ANSWERS: Answers to these questions will be in the OSP Expert column in the October issue of OSP magazine.

Signing off
If you have other questions that you think I should ask and that would benefit others, please share them: dmccarty@mccartyinc.com or 831.818.3930. And check out my TALK BACK online column and tell me what you think: http://www.ospmag.com/columnists/mccarty/talkback.