1-27
ANSWERS TO QUESTIONS Q1. THROUGH Q36.
A1. To allow comparisons between conductors of different sizes and resistance.
A2. 375 mils (move the decimal three places to the right).
A3. A circular conductor with a diameter of 1 mil and a length of 1 foot.
A4. The cross-sectional area of a square conductor with a side of 1 mil.
A5. The cross-sectional area of a circular conductor with a diameter of 1 mil.
A6. Circular mil area (CMA) = D2 (in mils)
number of strands0.0004 inch = 4 mils (CMA) = 4
2
19 (strands)(CMA) = 16
19 = 304 mils.
A7. The resistance of a unit volume of a substance.
A8. Length, cross-sectional area, and specific resistance of a unit volume of the substance from
which the conductor is made.
A9. 1,000 ft = 10.4 ohms1,500 ft = 1.5
0.4 = 15.6 ohms
A10. In the parallel walled slot not the circular area.
A11. Conductor size, the material it is made of the location of the wire in a circuit, and the type of
insulation used.
A12. FEP, extruded polytetrafluoroethylene, and silicone rubber.
A13. The heat surrounding the conductor is an important part of total conductor heating.
A14. It is light and reduces corona.
A15. It has higher conductivity, it is more ductile, it has relatively high tensile strength, and it can be
easily soldered.
A16. The amount of increase in the resistance of a 1-ohm sample of the conductor per degree of
temperature rise above 0º
C
A17. It increases.
A18. Conductors have a very low resistance and insulators have a resistance that is so great that, for
all practical purposes, they are nonconductors.
A19. Insulation resistance and dielectric strength.
A20. The resistance to current leakage through the insulation.
A21. The ability of the insulation material to withstand potential difference.
A22. By raising the voltage on a test sample until it breaks down.
A23. To prevent the rubber insulation from deteriorating due to chemical action.
A24. Avoid breathing the vapors when the insulation is heated.
A25. Breathing asbestos fibers can cause lung disease and/or cancer
A26. It will become a conductor.
A27. Varnished cambric and oil-impregnated paper.
A28. Magnet wire.
