TB- 8: Electrical Hazards at Fires Flashcards
Define AMPS.
Current flow/electron flow
*can be compared to flow of water through hose
Define VOLTS.
Difference in electrical potential
*compared to PSI in water hydraulics
Define OHMS.
Electrical resistance that determines current flow
*compared to friction loss
What is OHMs Law?
Relationship of power:
Watts-amps x volts
Amps-watts x volts
Volts-watts x amps
Define WATTS.
amount of current power times volts
What is the range for high voltage?
600 volts to 59,999 volts
What is low voltage
below 600 volts
What are the three systems that get electricity to
the consumer?
Generation, Transmission, Distribution system
What are the two main components of the
transmission system?
Grids
Transmission lines
What are overhead transformers?
pole mounted transformers installed on 4.8kV
lines stepping down power to 120/240 volts
What are the four main types of electrical injuries?
Electrocution, electrical shock, burns, and falls
Electrocution, electrical shock, burns, and falls
Cal OSHA requires ladders be how far away from
600 volts or more?
10 feet
Street lights can carry how many volts?
120-6150
When hose streams are utilized on electrical fires,
what guidelines should be adhered to?
30 degree fog pattern
33 feet from energized source
100 PSI minimum
Life hazard zones should be clearly identified by?
Minimum of 3 horizontal barrier tapes
Three 1” to 3” lettering on stationary objects
Vehicles should be driven clear of wires when
possible by how many feet?
at least 35
During brush operations, firefighters should?
-maintain distance of 35 ft from transmission towers
-maintain clearance of 100 ft from outermost wires
-never direct hose streams on smoke/fire within
100 ft of high voltage wires
What is the minimum distance kept from downed
power lines that have not been de-energized?
Distance equal to length between two poles
Man hole covers typically weigh? and can travel?
Weigh 300 lbs
Travel 75 ft in the air and distance of 125 ft.
In an emergency where high voltage wires need to be cut, member should?
Contact MFC for Water and Power line patrolman
who is available 24 hrs a day and usually within
10 minutes of any area in the city
Rubber gauntlet gloves are tested?
by DWP to 10,000 volts every 60 days
What is the definition of Extremely High Voltage?
Over 60,000 volts
There are 21 LADWP Receiving Stations. These
stations step the voltage down from what to what?
138kv - 500kv down to 34.5k
Wires on poles shall not be cut by firefighters
unless what situation exists?
There is an immediate life hazard
If the LAFD cuts wires, they must be below what
voltage?
600 volts
Aerial ladders must be kept at least how many feet away from wires and devices?
10 feet
When may aerials be operated within the 10’ rule?
Only to attempt an actual rescue
To work WITHIN the 10’ rule, what must be done?
A/O shall remain at pedestal to provide for
personnel safety
Normal communication lines mounted to the lowest level of power poles can be energized with up to how many volts?
50 volts
Ground ladders must be kept at least how far from overhead wires and transformers?
10 feet
Water by nature is not a good conductor, what two
factors increase the conductivity of water?
Dissolved minerals and impurities in the water
What is the explosive range for Carbon Monoxide
(CO)?
12.5 to 74%
What is the flash point of the cooling oil used in the transformers?
Below 300 degrees F
