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AO Study 2020 > *TB 8- Electrical Hazards > Flashcards

*TB 8- Electrical Hazards Flashcards

1
Q

Terminology: The push or pressure behind current flow through a circuit is know as?

A

Volts

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2
Q

Terminology: _______ determines how much current will flow through a component.

A

Ohms

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3
Q

Amps x volts = ?

A

Watts (power)

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4
Q

High voltage is ranges from _____ to _____. Also referred to as “primaries”

A

600 to 59,999v

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5
Q

Low voltage is usually below _____ volts also referred to as “secondaries”

A

600v

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6
Q

Extremely high voltage is considered in excess of ______ volts

A

60,000v

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7
Q

All voltages above ________ volts are referred to as transmission voltages.

A

69,000v

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8
Q

Sub-transmission lines are considered to have __________ volts

A

34,500v

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9
Q

At a distribution station, electricity is received at ______ volts and stepped down to _____ volts

A
  1. 34,500v

2. 4,800v

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10
Q

Lines that carry 4,800 volts and run from the distribution stations to the neighborhood it feeds are known as what “type” of power lines?

A

primary lines or “primaries”

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11
Q

A receiving station takes high voltage from transmission lines and steps the voltage down to what?

A

34,500 volts

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12
Q

A ___________ is designed to reduce the voltage in the system to a voltage usable by the consumer.

A

Transformer

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13
Q

Pole-mounted transformers are installed on 4,800v circuits and step the voltage down to _____ volts

A

120/240 volts

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14
Q

Underground electrical lines can be found in conduits or ducts and are identified by warning signs labeled ______

A

UG (underground)

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15
Q

Electrical distribution lines placed directly in the ground are designated as _________

A

DB (direct buried)

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16
Q

High voltage capacitors are dangerous because?

A
  1. They can hold a charge for weeks even if power was shutdown to the circuit
  2. Contain dangerous chemicals
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17
Q

________ are appliances which will prevent the flow of electricity and provides support to the conductor.

A

Insulators

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18
Q

Insulators are mostly made of _____ or _____

A

Glass or porcelain

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19
Q

The service connection that uses three conductors twisted around each other is know as a _______

A

Triplex

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20
Q

The 3 most effective methods of identifying high voltage on a pole are?

A
  1. High voltage sign on cross arms
  2. Size and shape of insulators (large = high volts)
  3. Distance between conductors (wires)
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21
Q

What are the four main types of electrical injuries?

A
  1. Electrocution
  2. Electrical shock
  3. Burns
  4. Falls
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22
Q

Firefighters responding to emergencies involving electrical equipment must wear what kind of PPE’s?

A

Full turnouts with hood and firefighting gloves

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23
Q

There are two main methods for de-energizing a building are?

A
  1. Throw the main switch or breaker switched at electrical panel
  2. Cut wires with LAFD equipment
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24
Q

Besides wearing full firefighting turnouts while shutting down power at the electrical panel, what else SHALL be worn?

A

Eye protection, consider scba face piece

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25
Q

Is the LAFD able to cut high voltage wires in the case of an emergency?

A

No, contact MFC to have DWP respond

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26
Q

Aerial ladders must be kept at least _____ feet away from all power lines and devices.

A

10ft

27
Q

The aerial ladder shall not work in violation of the 10-foot rule from electrical wires unless?

A

Participating in a rescue attempt

28
Q

During a rescue attempt with the aerial ladder, can any member remain at the pedestal to operate the ladder?

A

No, it SHALL be the apparatus operator

29
Q

Even if a wire is not electrical, should it be considered charged?

A

Yes, additional wires may have fallen and charged them

30
Q

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

A

50v

31
Q

If an apparatus becomes energized, what must be announced so other members on scene are aware of the danger?

A

Emergency traffic

32
Q

If an apparatus becomes energized with a downed high voltage wire, can LAFD members raise or move the wire to de-energize the apparatus?

A

No, call for LADWP

33
Q

Keep ground ladders at least ____ feet from wires

A

10ft

34
Q

For a downed overhead wire, have responding personnel maintain at least ___ span(s) from the affected wire or pole

A

One

35
Q

“One span” is considered the distance between how many poles?

A

2 poles

36
Q

For optimum safety, the distance between how many undamaged poles will provide the best margin of safety?

A

2 undamaged poles

37
Q

What should be the LAFD actions when water from a sheared hydrant is contacting overhead electrical wires?

A

Call and wait for DWP, unless a life hazard exists

38
Q

What should be the firefighting actions for an overhead or pad mounted transformer fire?

A

Secure scene and protect exposures

Extinguish once DWP has de-energized

39
Q

Streetlights can be fed from conductors carrying ____ to ____ volts or more.

A

120-6150v

40
Q

Are street lights considered low or high voltage?

A

High voltage

41
Q

What should be the firefighting actions for a street light fire?

A

Secure scene and protect exposures

Extinguish once de-energized by DWP

42
Q

What should be the firefighting actions for a distribution/substation fire?

A

Secure scene and protect exposures

Extinguish once de-energized by LADWP

43
Q

What are the LAFD actions in case of rescue in a distribution station?

A

Have victim remain stationary until LADWP gives clearance for rescue

44
Q

What is the “rule” developed for using hose streams around high voltage?

What does it stand for?

A

30/33/100 rule

30 degree fog pattern
33 feet away from energized source
100psi minimum to nozzle

45
Q

Where possible, extinguish small electrical fires with what two types of extinguishers?

A

Dry chemical or carbon dioxide extinguishers

46
Q

The method to assure that fire personnel do not enter Life Hazard Zones includes the use of a minimum of ______ horizontal strands of barrier tape that state “Do Not Enter” or “Do Not Cross”.

A

3

47
Q

If the driver of a vehicle in contact with downed wires is able to drive the vehicle, it should be driven clear of the wires by at least ____ feet.

A

35ft

48
Q

Instructing victims to exit a charged vehicle should only be done when?

A

A life threatening emergency exists

49
Q

The main fire hazard within electrical vaults lies in the _______ used in the transformers, which has a flash point below _____F.

A
  1. Cooling oil

2. 300

50
Q

How much do manhole covers weigh?

A

300 lbs

51
Q

How high can a manhole cover be blown into the air and at what distance can it end up?

A
  1. 75 ft

2. 125 ft

52
Q

___ of an amp of electricity going through the body for just 2 seconds is enough to cause death

A

1/10th

53
Q

When cutting wires at the drip loop with LAFD equipment, cut which wire (conductor) first?

A

Closest

54
Q

Per T.B. 49:

All Water and Power capacitors, transforms, regulators, and resistors are labeled with a ___ inch x ___ inch yellow and black sign indicating that the equipment contains PCB’s

A

2” by 2”

55
Q

Voltages on transmission lines range from ___ kv to over ___kv.

Most of the transmission lines coming into Los Angeles are ____kv

A

60kv to 1000kv

230kv

56
Q

Pad mounted transformers are connected to ___kv circuits and are located in parking lots of small and medium size businesses or in the front yard of some residences.

A

48

57
Q

Underground distribution lines can be found in what three configurations?

A
  • underground
  • subsurface
  • direct buried.
58
Q

At 600 volts, the current through the body may be as great as ___ amps

A

4

59
Q

Voltage _______ is a decreasing current created when a energized wire is in contact with the earth.

A

Gradient

60
Q

What are the three significant methods that can result in electrocution at an emergency involving electrical equipment?

A
  1. Voltage gradient
  2. Touch potential
  3. Step potential
61
Q

What are the two methods used when instructing a patient to exit an electrically charged vehicle where a life treating emergency exists?

(Firefighters must not approach or grab victim)

A

Jump from the vehicle and:

  1. Keeping feet together and taking small hops away
  2. Shuffling feet together
62
Q

A transformer vault has a _____ shaped manhole cover

A

Square

63
Q

Terminology: Current flow or electron flow is known as?

A

AMPS

AO Study 2020 (101 decks)

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