Electrical Principles and Wiring Materials

Question 1

is a form of energy that can produce light, heat, magnetism, chemical changes

Answer 1

Electricity

Question 2

tendency of a material to prevent electrical flow

Answer 2

Resistance

Question 3

if electricity flows easily

Answer 3

Conductor

Question 4

material that provides great resistance

Answer 4

Insulator

Question 5

measure of the rate of flow of electricity in a conductor

Answer 5

Amps

Question 6

measures of electricity pressure

Answer 6

volts

Question 7

measure of the amount of energy or work that can be done

Answer 7

watts

Question 8

measure of electricity resistance to flow

Answer 8

ohms

Question 9

• Power from power company
• Transformer: drop volts from 25,000 volts to 240 volts
• Service drop: wires etc from transformer to house
• Entrance head: weather-proof at house
• Meter: $$
• Service Entrance Panel (SEP): box with fuses or breakers

Answer 9

Service Entrance

Question 10

-Kilowatt hours: how electricity is sold
-Kilo = 1000
-Watthour = use of 1 watt for one hour
> 100 watt light bulb for
1 hour - 100 watt hour
-Kilowatt hour = 1000 watt for one hour

Answer 10

Electric meter

Question 11

• Usually begin at SEP
• Branch out into a charity of places
• Only 1 motor or;
• Series of outlets or;
• Series of lights
• Use correct size wire and fuse or breaker
• Service drop: 200 amps, 240 volts

Answer 11

Branch circuit

Question 12

copper or aluminum wire covered with paper, rubber, or vinyl for insulation

Answer 12

nonmetallic sheathed cable

Question 13

flexible metal sheath with individual wires inside. Wires are insulated

Answer 13

Armored cable

Question 14

tubing with individually insulated wires

Answer 14

conduit

Question 15

NEC

Answer 15

national electric code

Question 16

• No 14 (14 gauge) = 15 amp circuits
• No 12 =20 amps
• No 10 = 30 amps

Answer 16

Copper

Question 17

• use one size larger
• Lower gauge number = larger wire
• No 8 = 40 and larger use bundles of wires
• Current travels on outer surface of wire, so bundle of smaller wire can carry more

Answer 17

Aluminum

Question 18

• Loss of voltage as it travels along a wire
• Lights dim, motors overheat
• Larger wires have less voltage drop for a given amount of current
• Longer wire = greater problem
• Must increase wire size as distance increases

Answer 18

voltage drop

Question 19

Type of outer covering, individual wire covering, cable construction, number of wires.
Wire types stamped on the outer surface.

Answer 19

wire identification

Question 20

Type T-

Answer 20

dry locations

Question 21

type TW

Answer 21

dry or wet

Question 22

THHN

Answer 22

dry, high temps

Question 23

THW and THWN

Answer 23

wet, high temps

Question 24

XHHW

Answer 24

high moisture and heat resistance

Question 25

UF

Answer 25

direct burial in soil but no concrete

Question 26

positive or hot wires which carry current to appliances | color coded

Answer 26

black, red, and blue

Question 27

neutral wires carry current from appliance back to source | color coded

Answer 27

white

Question 28

ground all metal boxes and appliances | Color coded

Answer 28

Green or bare

Question 29

12-2 has two strands of No. 12 wire

Answer 29

black and white

Question 30

12-3 has three strands of No. 12

Answer 30

black, red, white

Question 31

12-3 w/g same,

Answer 31

with green or bare

Question 32

``` Shock and fire Never disconnect any safety device Don’t touch electrical items with wet hands or feet Don’t remove ground plug prong Use GFCI in wet areas Discontinue use of extension cord that feels warm Don’t put extension cords under carpet Install wiring according to NEC ```

Answer 32

Electrical safety

Question 33

Blown fuse or breaker, determine cause Don’t replace fuse with larger fuse don’t leave heat producing appliances unattended Keep heaters and lamps away from combustibles don’t remove back of TV (30,000v when off) Electric motors are lubricated, free of grease etc. Keep appliances dry Don’t use damaged switches, outlets, fixtures, extension cords Follow manufacturer's instructions for installation and use of electrical equipment Never work in the circuit while it’s plugged in. always disconnect the lead from the source

Answer 33

Electrical safety

Question 34

Before powering up the circuit, make sure all wires are properly connected Never run the circuit with an exposed wire Never touch an exposed wire while connected Never allow exposed wires to touch. It creates a short If you are unsure if you are allowed to plug in the circuit, ask me If an emergency occurs, get my attention immediately

Answer 34

Electrical safety

Question 35

what are three kinds of circuits

Answer 35

series parallel series parallel

Question 36

Electrical that only has one path for electrons to flow. Open Loop - the circuit is not complete. In simple terms, the switch is open, not allowing electrons to flow to the load to complete the circuit.

Answer 36

Series circuit

Question 37

The loads are connected between the two conductors that lead to the energy source. There is no voltage drop if two or more loads are connected in parallel. Example - a vanity light that has three lights. If wired in parallel, the voltage at all three loads is 120V, same as the source. If wired in series each light bulb would produce only 40 volts each

Answer 37

Parallel circuit

Question 38

Loads operate independently. Meaning one switch to a light can be turned off, but another can still operate. Example of a parallel circuit- In your kitchen, you might have 3 different lights. Each has their own switch. However, they are connected on the same line, at the breaker box. Hence, there are different lines going to each load from the source.

Answer 38

series parallel