1. A.

It is a technique typically engaged in electrical power and electronic devices, wherein the devices are run at less than their rated maximum power degeneracy, taking into account the case or body temperature, the ambient temperature and the type of cooling mechanism used.

2. B.

In order to answer the question, you need to know the area of a circle.

Area = pi * r^2

Area = 3.14 * (100/2) ^ 2

Area = 3.14 * 50^2

Area = 7850 mils^2 = 0.00785 in^2

3. A.

V / 15 A = 0.213 Ohm

0.213 Ohm / 125 ft * 1000 ft = 1.71 Ohm / 1000 ft

Closest gauge is #12 AWG (solid wire)

#12 is 1.588 Ohm / ft, which is a 2.9775 V drop @ 15A

4. A.

RHW cale insulation can be used up to 167 degrees F.

5. D.

This is a type of electrical connector used to fasten two or more low-voltage (or extra-low-voltage) electrical conductors.

6. C. the ease with which a material allows electricity to move is called CONDUCTIVITY

7. D.

Stranded conductors are not acceptable in the pressure terminals of a duplex receptacle. Aluminum conductors of suitable gauge for a 15 ampere duplex outlet will not fit in the pressure terminal holes.

8. D.

A 3/0 AWG THHN insulated Copper is rated at 225 amps and it falls under the 90 degree C table.

9. D.

A #12 copper conductor with an insulation factor of 90 degrees C is rated at 20 amps. A #12 aluminum conductor with an insulation rating of 90 degrees C is rated at 15 amps. These conductors ratings only applies to three conductors in a rated at 15 amps. These conductors’ ratings only applies to three conductors in a raceway. From 7 to 24 conductors in a raceway, both aluminum and copper conductor’s ratings have to be reduced by .70, so 15 amps x .7 = 10.5 amps and 20 amps x .7 = 14 amps respectively.

10. A.

NEC 310.15(B)(1) and (2), table 310.15(B)(2)(a), and table 310.15(B)(17).

Convert 158°F to C result is 70°C. 50 amps x .33 correction factor = 16.5 amps

11. A.

12. B.

Ideally, nm or armored cable should be installed in a wall stud at least 1 1/4 inches from the front edge of the stud.

13. C.

Always use flux for electrical connections and never use acid flux on electrical connections

14. D.

In wire gauge, the lower the number, the larger the diameter. So a 6 gauge is larger than 12 gauge, but smaller than 4 gauge.

15. A.

16. D.

17. C.

Table 310-16 NEC

18. A

MCM means 1000’s (M) of (C)ircular (M)ils

19. D.

Rubber tape is used to round sharp edges

20. B.

The larger the diameter, the larger the ampacity, or the ability to carry current.