Ch 21 Electrical Fires and Emergencies Flashcards
What we has what? Pg 523
Pressure, friction loss, and flow rate
Electricity has what? Pg 523
Pressure, known as electromotive force or electrical potential difference, and is measured in volts.
What is friction loss? Pg 523
Which is a measure of the resistance that it meets, is measured in ohms.
The flow rate in water is referred to what? Pg 523
In terms of gallons per minute, with electricity, it is called amperes (commonly referred to as amps for short).
Amperage is what? Pg 523
Is determined by the amount of voltage the conductor is delivering and the resistance that the wire or object in the path of the current is offering.
It takes far less than how many amp passing through your body to kill you? Pg 524
1
What is voltage? Pg 524
Can be described as the pressure that forces electrical current through the lines that carry it.
Many utilities refer to anything less than how many volts as low voltage? Pg 524
600
Resistance can be thought of in terms of what? Pg 524
Resistance to flow offered to the electricity.
A open circuit is what? Pg 524
Is an electrical circuit that does not permit electricity to flow because there is a break in the circuit wire or an open switch
What is a short circuit? Pg 524
When an electrical circuits normal path has been interrupted, current is permitted to flow through a path it was not intended to.
What is a utility ground? Pg 524
The wiring installed by the utility companies that permits electricity to flow back into their system and then into the earth or ground
What is a house ground? Pg 524
The wiring installed by the electrician when building a house that also permits electricity to flow back into the earth or ground in the event the utility ground is broken or open.
The black wire is called what? Pg 525
Hot wire
The white wire is called what? Pg 525
Neutral
There are two main hazards from electricity? Pg 527
Electrocution and burns
Alternating current flow hazardous to humans? Pg 527
• 1-5 mA: tingling sensation
• 5-10mA: pain
• 15 mA: Level where muscle construction prevents letting go of a wire in the hand.
• >50 mA: Loss of muscle control, cessation of heart and respiratory functions, death
All ladders and other equipment must be kept at least how many feet from overhead power lines? Pg 528
10 ft
What is voltage gradient? Pg 529
Is the result of current being dissipated to ground as it travels from a source. Such as downed high voltage wire.
Transmission line voltage carry likely exceeds how many volts? Pg 530
8,000 volts
Distribution line voltage carry between how many volts? Pg 530
601 and 8,000 volts
Initial responders should isolate the area at least what distance away from any break? Pg 538
At least one full wire span.
Keep at least how many feet away when using a fog nozzle from all electrical equipment when operating any handling? Pg 538
25 ft
Keep at least how many feet away when using a solid tip nozzle from any electrical equipment when operating handline? Pg 538
40 ft
How many full spans greater than the affected span should the perimeter of the operation when encountering downed power lines? p. 537
One
What is the minimum distance that all ladders and other equipment should be kept from overhead power lines?
Pg 528
10 feet
Which type of circuit does not permit electricity to flow? p. 524
Open
How should you hold your hand out if you must move through an area containing electrical hazards with low visibility? p. 535
Palms turned back toward your body
Which is a correct assumption about voltages in transmission lines? p. 530
Higher voltage lines are placed higher on the pole
What smell does the overheated ballast give off? p. 540
Oily
Which type of fire is a transformer primarily classified as being? p. 532
Oil
Which type of circuit has been created when the normal path has been interrupted and the current is permitted to flow through a path it was not intended to? p. 524
Short
What is the correct sequence when a hot stick is being used to remove a live wire from a victim? p. 538
Place the clamp under the wire and twist the body of the
stick clockwise
Which is a poor conductor of electricity? p. 524
Glass
Which is NOT a correct statement about operations at the generating station? p. 531-532
Enter fenced off areas with caution and a handline
What handline should always be stretched during operations at downed power lines where the lines are on a vehicle? p. 540
1 3/4-inch with a fog nozzle
What is the second grounding path normally attached to to guard against injury during a short circuit? p. 535
Cold water pipe
What is used to cool the generators in a power-generating station? p. 531
Hydrogen
What is the most frequent response to electrical emergencies in many urban areas? p. 533
Manhole fires
What is the most important thing that firefighters should be aware of in regard to the transmission system?
p. 525
High-voltage wires on poles are not insulated
What should handlines be stretched to do at a transformer fire? p. 532
Protect the exposures
What should be done once the spilled gasoline has been flushed away with the fog nozzle at a downed power line
incident with lines on a vehicle? p. 540
Cover with foam
What should the occupants of the vehicle with wires down on it be instructed to do if fire is threatening them? p. 539
Jump clear of the vehicle without touching the vehicle and
the ground at the same time
What can the size of the insulators located on transmission lines tell you?
p. 526
Level of voltage
What is an indicator of an ongoing electrical arc at manhole fires?
p. 533
Rumbling
What can be used to wrap visibly exposed wires when found at the base of lampposts? p. 536
Electrical tape
