Flashcards in Ch. 20 Electrical Fires and Emergencies Deck (60)
Water had pressure, friction loss and flow rate:
Pressure = volts (electromotive force OR electrical potential difference)
Friction loss = ohms (resistance)
Flow rate = amperes (amps)
Resistance occurs due to ___________.
The material of the conductor
_______ does not permit electricity to flow because there is a break in the circuit wire.
When an electrical circuit's normal path has been INTERRUPTED, it becomes _________ , permitting current to flow through a path it was not intended to travel.
A short circuit
Wiring installed by _________ that permits electricity to flow back into THEIR system and then into the earth is called:
Utility companies, Utility ground
Many rubber and plastic compounds are
Firefighting boots, either rubber or leather, are ___________ however, because of many other compounds they contain.
Not good insulators
Most electricity is produced by ______, in facilities that use fuel as sources of energy (____, ______, _____, or ______). Electricity is generally produced at ___________.
Coal, oil, gas or nuclear
Upon leaving generating stations, electricity travels through transformers that:
Increase it's voltage to 138,000-345,000 volts
(Voltage) Stepping down done in several stages, in different locations: (4)
Transformers inside buildings
Most IMPORTANT thing for firefighters to be aware of in regard to the TRANSMISSION system is:
High-voltage wires on poles ARE NOT insulated.
** also true of buss bars (bus bars) in OUTDOOR SUBSTATIONS***
Once at the point of distribution, other transformers reduce the voltage to:
Electricity is then fed through a grid of cables/transformers that take it right to the customers door. On the way, the voltage is:
Further stepped down to 120 or 240 volts normally used in the home or the office
_____ is moving force that travels through solid, liquid, and gaseous materials in the form of electron transfer from one molecule to another.
Economy of high-voltage transmission uses ________ between lines instead of _______. Distance is _______.
An air gap
It would be _______ to state that the larger the line, the higher the voltage.
In some cases, a larger transmission line carries _____ voltage than a small one
- depending on ______ and its ____________.
-the type of metal
Two main hazards with electricity:
_______ flows through the body, either due to high-voltage or low resistance, cause ______.
Amount of ________ through the body to produce injury or death is __________.
Very, very small
_____ and _______ are important factors that help determine whether a person survives a contact with electricity.
Size of contact point
Path electricity takes through the body to ground
Electrocution is affected by several variables: (5)
-amount of current
-size on contact point
-path to enter/exit the body
-duration of current flow
-condition of skin (wet, dry, broken)
It is usually the presence of _____ or ________ that triggers the response of firefighters.
The result of it
________ is one very common occurrence of such static arcing
______ is the result of current being dissipated to ground as it travels from a source, such as downed high voltage wire.
Carries vary in voltage potential, depending on the stage of transmission:
Transmission line = exceed 8,000 volts
Distribution line = potentials of 601-8,000 volts
Low-voltage potentials = up to and include 600 volts
System for distribution of electricity includes a combination of transformers with ___________, arranged in __________
High and low-power carriers
Series and parallel grid systems
In most power generation plants, the ______________ has access to emergency operations cabinet (station diagrams, system/relay drawings, log books, current list of all equipment containing PCB's)
Watch general supervisor
Charts that show emergency posts and jobs for all staff can in large plants number more that ______.
Transformer is atop a pole, make no attempt to extinguish fire unless:
-could result in wire breakage