Electrical Questions From Notes

Question 1

Vertical clearance for overhead service conductors

Answer 1

10 feet - at the electrical service entrance to a building, also at the lowest point of the drip loop of the building electrical entrance , and above areas or sidewalks accessible only to pedestrians, measured from the final grade or other accessible surface only for overhead service conductors supported on and cables together with a grounding bare messenger wire where the voltage does not exceed 150 volts to ground
12 feet - over residential property and driveways and commercial property not subject to truck traffic, where the voltage exceeds 300 volts to ground
15 feet - areas listed in 12 feet where the voltage exceeds 300 volts to ground
18 feet - over public streets alleys roads parking subject to truck traffic. Driveways on other than residential property, other land such as cultivated grazing forest or orchard
24 1/2 feet - over railroad tracks

Question 2

1 HP equals how many watts

Answer 2

746 watts

Question 3

Power factor equation

Answer 3

PF = W/VA

Question 4

Fixed heat detector temp

Answer 4

135F

Question 5

According to the NEC, an assembly is a place where how many people gather

Answer 5

100

Question 6

12 awg KCMIL

Answer 6

6,530

Question 7

Resistance of 14 awg per 1000 feet

Answer 7

3.14 ohms

Question 8

Resistance of 12 awg per 1000 feet

Answer 8

1.98

Question 9

Transformer short circuit formula

Answer 9

Amps = power / (volts x impedance)

Question 10

Class I,II,III corospond with what materials

Answer 10

Gas
Dust
Fibers

Question 11

What size wires and up need to be stranded when in a raceway?

Answer 11

8 awg

Question 12

Amperage of 50 hp 3 phase 208v squirel cage motor

Answer 12

143 amps

Question 13

3 phase voltage coefficient

Answer 13

1.732. Square root of 3

Question 14

Short circuit rating of a 500kva transformer 240v with 1 percent impedance?

Answer 14

208,333 amps

Question 15

Balcony, deck, patio max receptacle height

Answer 15

6.5 feet

Question 16

Can strut type channel raceway penetrate walls?

Answer 16

Yes
384.10(6)

Question 17

If a single receptacle is installed on a 20 amp circuit, does that receptacle need to be a 20 amp receptacle

Answer 17

True
Duplex receptacle is 2 receptacles

Question 18

At carnival rides, where shall the disconnecting means for each structure be located

Answer 18

Within sight and 6 feet of the operator

Question 19

Pool equipotential bonding must be done with what size wires

Answer 19

8 awg copper

Question 20

A detached building supplied by one multi wire branch circuit shall have a grounding electrode installed? True or false?

Answer 20

False

Question 21

Transformers operate on the principle of what?

Answer 21

Mutual inductance

Question 22

Circuit breakers shall have what visible after installation?

Answer 22

Ampere rating
240.83 (A)

Question 23

A unit of an electrical system, other than a conductor, that carries or controls electric energy as its principe function

Answer 23

Device

Question 24

The prospective symmetrical fault current at a nominal voltage to which an apparatus or system is able to be connected without sustaining damage exceeding defined acceptable criteria

Answer 24

Short-Circuit current rating

Question 25

Chico thickness

Answer 25

5/8”

Question 26

Resistors in parallel formula

Answer 26

1/Rt = 1/R1 + 1/R2 + 1/R3

Question 27

Adjustment factor for more than 3 Current carrying conductors

Answer 27

4-6 80% 7-9 70% 10-20 50% 21-30 45% 31-40 40% 41 and above 35%

Question 28

Max outlets on a 15 and 20 amp circuit

Answer 28

15 max is 10 20 max is 13

Question 29

Show window VA calculation

Answer 29

200 va per foot

Question 30

Demand factor for 5 residential dryers

Answer 30

85%

Question 31

2 ohms laws equations to remember

Answer 31

V=IR P=IV