TB-8 Electrical Hazards

Question 0

Amps can be described as:

Answer 0

Current or electron flow.

Current flows from points of high voltage to low voltage on the surface of a conductor.

Question 1

Electrocutions have resulted in more than ____ deaths in the fire service in the last 20 years.

Answer 1

25

Question 2

Volts:

Answer 2

Push or pressure behind current flow through a circuit. (psi)

Voltage is the difference in electrical potential between two points in a circuit.

Question 3

Ohms:

Answer 3

Resistance

Question 4

Ohms Law:

Answer 4

Watts=amps x volts
Amps=watts/volts
Volts=watts/amps

One ohm is the resistance value through which one volt will maintain a current of one ampere.

Question 5

Watts:

Answer 5

Watts=amps x volts

Power is the amount of current times the voltage level at a given pint measured in wattage or watts.

Question 6

What is considered extremely high voltage?

Answer 6

Voltages in excess of 60,000 volts. Usually transmission voltage.

Question 7

High voltage is:

Answer 7

Voltage from 600 volts up to 59,999 volts.

primaries

Question 8

Low voltage:

Answer 8

Usually below 600 volts.

secondaries

Question 9

Getting electricity to the consumer can be broked down into 3 systems, ___________,_____________, and _____________.

Answer 9

Generation, Transmission, and Distribution System.

Question 10

Generation facilities produce between __________ and ____________ volts.

Answer 10

4,000 and 20,000 volts

Question 11

Voltages on transmission lines range from _______ to _________.

Answer 11

69kv to 1000kv.

All voltages above 69kv are referred to as transmission voltages.

Question 12

Strings of insulators on transmission towers can range from ____ to ____ ft long.

Answer 12

3 to 20 ft.

Question 13

What are the dangers of a high voltage capacitor?

Answer 13

They can retain a deadly electrical charge even weeks after the power has been removed from the circuit. Older versions contain dangerous chemicals.

Question 14

Overhead transformers are installed on the 4.8kv circuits to step down the voltage down to _____/______ volts.

Answer 14

120/240

Question 15

True or false? The voltage of a conductor can be determined by the conductor’s size.

Answer 15

FALSE

Question 16

The three most effective method of identifying different voltages are:

Answer 16

1. High voltage signs on the cross arms.
2. The size and shape of insulators, the insulators at the tops of poles will appear smaller than they really are.
3. The distance between the conductors. The higher the voltage, the greater the distance between conductors.

Question 17

The four main types of electrical injuries are:

Answer 17

Electrocution (death)
Electrical shock
Burns
Falls

Question 18

For example, ____ of an amp of electricity going through the body for just two seconds is enough to cause death.

Answer 18

1/10

Question 19

For every minute that defibrillation is delayed, the patient sustains a ____% reduction in their chances of survival.

Answer 19

10

Question 20

The most common shock related injury, non fatal injury is a ______.

Answer 20

burn

Question 21

Ultimately, the danger from electrical shock depends on the:

Answer 21

AMOUNT, DURATION, and PATH of the shocking current through the body.

Question 22

When a burn injury does not meet base station criteria, the member shall be transported directly to ________, or ___________.

Answer 22

Grossman Burn Center at West Hills Hospital or Torrance Memorial Hospital Burn Center.

Question 23

Overhead communication cable normally found on the lowest level of a power pole can be energized up to ____ volts. Can cause a fall off the aerial.

Answer 23

50

Question 24

When spotting apparatus, have personnel maintain at least ___________ from the affected wire or pole.

Answer 24

One span (distance between two poles).
Do not count damaged pole.

Question 25

Street lights can be fed from conductors carrying _______ volts or more.

Answer 25

120-6150 volts

Question 26

The factors that increase the conductivity of water are ________ and ________ in water.

Answer 26

dissolved minerals and impurities

Question 27

Use the 30/33/100 Rule for using hose streams around high voltage:

Answer 27

1. 30 degree fog pattern
2. Stay 33 feet away from the energized source.
3. 100 psi at the nozzle.

Question 28

For victims trapped in a car touching wires, the vehicle should be driven clear of the wires by at least _____ ft.

Answer 28

35

Question 29

A charge of static electricity capable of jumping ____ to ____ inches may build up in a person’s body when climbing a tower.

Answer 29

2 to 3

Question 30

During brush fires, maintain a distance of ____ feet from transmission towers.

Answer 30

35 feet.

Question 31

During brush fires, maintain a clearance of ____ feet beyond the outermost wire of electrical transmission lines.

Answer 31

100 ft.

Question 32

During brush fires, never direct hose streams into heavy plumes of smoke within ____ feet of high voltage wires.

Answer 32

100

Question 33

The explosive range for carbon monoxide is _______ percent.

Answer 33

12.5 to 74

Question 34

Manhole covers often weigh _____ and have been blown ____ feet into the air and a distance of _____ feet.

Answer 34

300 lbs, 75 feet into the air, and a distance of 125 feet.

Question 35

The apparatus is not insulated from the ground by its rubber tires and it may be energized by live wires in the following ways:

Answer 35

• By touching an object that is in contact with a live conductor
• By direct contact with a live conductor
• By an extended aerial ladder touching a live conductor

Question 36

A square manhole indicates a ________________.

Answer 36

Transformer vault

Question 37

The main hazard within electrical vaults lies in the ________ used in the transformers, which has a flash point below _________.

Answer 37

Cooling oil, 300 F

Question 38

High voltage cables, up to _________volts, may be located close to the floor inside a conduit containing ______ psi oil pressure.

Answer 38

230,000 volts, 200 psi oil pressure