TB Electrical Hazards Continued.

Question 1

Overhead Transformers - Pole-mounted transformers are the most ___ distribution transformer.

Answer 1

common

Question 2

Overhead Transformers -

They are installed on the 4.8kv circuits to step the voltage down to ___ volts for most residential consumers.

Answer 2

120/240

Question 3

Transformers for subsurface electrical are mounted above ground on concrete bases called ____.

Answer 3

pad-mounted transformers

Question 4

Pad-mounted transformers :
These large boxes are connected to ____ circuits and are located in parking lots of small and medium size businesses or in the front yard of some residences.

Answer 4

4.8kv

Question 5

The conductors are materials that allow an electric current to flow through them ___.

Answer 5

easily.

Question 6

Insulators are appliances which will ___ the flow of electricity and provides support to the conductor. They are most commonly made of glass or porcelain.

Answer 6

prevent

Question 7

The most effective methods of identifying different voltages are:
1. ___ signs on the cross arms.

Answer 7

High voltage

Question 8

The most effective methods of identifying different voltages are:
2. The size and shape of ____; remember, the ___ at the top of poles will appear smaller than they really are.

Answer 8

insulators

Question 9

The most effective methods of identifying different voltages are:
3. The distance between ___; the higher the voltage, the greater the distance between _____.

Answer 9

conductors

Question 10

Common Electrical Distribution Lines:

Primary wires = up to ____ volts of electricity

Answer 10

21,000

Question 11

Common Electrical Distribution Lines:

Secondary wires = up to ____ volts of electricity

Answer 11

240

Question 12

Common Electrical Distribution Lines:

Transformer = reduces ____ voltage to secondary voltage

Answer 12

Primary

Question 13

Common Electrical Distribution Lines:

Electric Service = to house up to ___ volts of electricity

Answer 13

240

Question 14

Common Electrical Distribution Lines:

Lowest lines =

Answer 14

Phone and Cable service

Question 15

___ of an amp of electricity going through the body for just ___ seconds is enough to cause death.

Answer 15

1/10 / two

Question 16

The amount of internal current a person can withstand and still be able to control the muscles of the arm and hand can be less than _____.

Answer 16

10 milliamps (mA).

Question 17

Currents above ____ can paralyze or “freeze” muscles.

Answer 17

10 mA

Question 18

People have stopped breathing when shocked with currents from voltages as low as ___ .

Answer 18

49 volts

Question 19

Usually, it takes about ___ of current to cause respiratory paralysis.

Answer 19

30 mA

Question 20

Currents greater than ___ may cause ventricular fibrillation (very rapid, ineffective heartbeat).

Answer 20

75 mA

Question 21

Heart paralysis occurs at ____, which means the heart does not pump at all. Tissue is burned with currents greater than 5 amps.

Answer 21

4 amps

Question 22

At ___ volts, the current through the body may be as great as 4 amps, causing damage to internal organs such as the heart.

Answer 22

600

Question 23

Dry skin may have a resistance of ___ ohms or more. Wet skin may have a resistance of only 1,000 ohms.

Answer 23

100,000

Question 24

The cutting of wires by firefighters must be confined to ____ wires.

Answer 24

low-voltage

Question 25

Voltage Gradient: Is a ____ created when a energized wire is in contact with the earth.

Answer 25

decreasing current

Question 26

Touch Potential: Occurs by contacting a ____ source. Touch potential commonly occurs when a vehicle, fence, or other conductor is in contact with a live conductor such as a downed wire.

Answer 26

live or energized

Question 27

Step potential: Occurs when responders or victims create a ______ as they walk over or across a voltage gradient created by an electrical source, such as a downed wire.

Answer 27

circuit with their feet

Question 28

Even overhead communication cable normally found on the lowest level of a power pole can be energized with up to ___.

Answer 28

50 volts

Question 29

Spot apparatus and have responding personnel maintain at least one span (____) from the affected wire or pole.

Answer 29

the distance between two poles

Question 30

For optimum safety, remember the distance between ___ poles will provide the best margin of safety.

Answer 30

two undamaged

Question 31

Pad-mounted fires should be treated the same as overhead transformers by____, protect exposures and keep people away from the area.

Answer 31

letting them burn

Question 32

Overhead Transformers :

Applying water should be ___ as it is not effective and it can cause adjacent wires to fall.

Answer 32

avoided

Question 33

Streetlights can be fed from conductors carrying ___ volts or more.

Answer 33

120-6150

Question 34

Utilize a ___ stream. The air spaces between the drops of water in the stream limit electrical conductance.

Answer 34

fog

Question 35

Utilize the 30/33/100 Rule for using hose streams around high voltage:
The fog spray should be set at a _____ fog pattern. Straight streams or foam should not be used on high voltage sources.

Answer 35

30-degree

Question 36

Utilize the 30/33/100 Rule for using hose streams around high voltage:
Firefighters applying water should maintain a distance of at least ____ from the energized source.

Answer 36

33 feet

Question 37

Utilize the 30/33/100 Rule for using hose streams around high voltage:
Ensure a minimum of ___. is pumped to the nozzle. A strong stream will reduce conductivity.

Answer 37

100 psi

Question 38

Occupants trapped : The vehicle should be driven clear of the wires by at least ____.

Answer 38

35 feet

Question 39

There are two methods that can be used from removing oneself from an energized vehicle:
Jump or leap from the vehicle without touching it, keeping both feet together and taking ___ from the car.

Answer 39

small hops

Question 40

There are two methods that can be used from removing oneself from an energized vehicle:
Jump from the vehicle without touching it and ___ the feet together.

Answer 40

shuffling

Question 41

Maintain a safe distance from transmission towers: a minimum of ____ should be adhered to.

Answer 41

35 feet

Question 42

Maintain clearance a minimum of ___ feet beyond the outermost wire of electrical transmission lines.

Answer 42

100

Question 43

Operations Near Transmission Lines:

Never direct hose streams at ______.

Answer 43

high voltage wires

Question 44

Operations Near Transmission Lines:

Keep hose streams ___ the height of individual operating it.

Answer 44

below

Question 45

Operations Near Transmission Lines:

Never direct hose streams into heavy plumes of smoke within ___ of high-voltage wires

Answer 45

100 feet

Question 46

With heavy smoke present, firefighters should be especially cognizant of remaining at least ___ from transmission lines and ___ from transmission towers.

Answer 46

100 feet / 35 feet

Question 47

The explosive range for carbon monoxide (co) is____ percent.

Answer 47

12.5 to 74

Question 48

Manhole covers often weigh 300 pounds and have been blown ___ into the air and a distance of ____.

Answer 48

75 feet / 125 feet.

Question 49

Remember that the main fire hazard within electrical vaults lies in the ____ used in the transformers, which has a flash point below ____.

Answer 49

cooling oil / 300F