Utility Emergencies Manual, 2ndEdition, April 2014 Flashcards
The flow of an electric current across a gap between two conductors, terminals, or contacts.
Arc
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A component that detects overload conditions and then disconnects and stops the flow of electrical current to protect and ensure safe operation of the system
Break (or Circuit Breaker)
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What does BLEVE stand for?
Boiling Liquid Expanding Vapor Explosion
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A path through which electric current is intend to flow.
Circuit
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Located at the top of a utility pole, a wooden bar to which power lines are attached.
Cross Arms
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What is the purpose of cross arms on a utility pole?
The cross arm keeps the lines separated by a sufficient distance to prevent arcing.
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This links the transmission system to most customers.
Distribution System
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This is a protective device, consisting of a conducting material, which melts and burns opening the circuit when a specified value is exceeded.
Fuse
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This means an item is designed to be incapable of producing heat or spark sufficient to ignite an explosive atmosphere.
Intrinsically Safe
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This is a device, which provides transition between underground cable to overhead lines or conductors.
Pothead
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Electrical service delivered between 2,000 and 50,000 volts to a distribution transformer, which, in turn, reduces voltage to secondary levels.
Primary
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This is an automatic protection device that senses and interrupts distribution system faults.
Recloser
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This is the conductor part of transition leading from underground to overhead; may or may not include pothead.
Riser
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Electric service taken at less than 2,000 volts. Most residential and business customers receive electricity from these distribution lines.
Secondary
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The process of opening switches or fuses to divide a circuit into section to isolate the cause of the power outage.
Sectionalize
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A quarter-turn valve used to restrict or isolate the flow of liquid or gas in a pipe.
Stopcock Valve
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A location, which uses a collection of transformers to reduce voltage and circuit breakers to protect circuits.
Substation
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This is an electrical outage that lasts for more than two minutes
Sustained Outage
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The ratio of the weight of a given volume of gas or vapor to the weight of an equal volume of air at the same temperature and pressure.
Vapor Density
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The average exposure to a contaminant or condition (such as noise) to which workers may be exposed without adverse effect over a period such as in an 8-hour day or 40-hour week.
Time Weighted Average (TWA)
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A device, which transforms electric energy from one voltage level to another level.
Transformer
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This system carries electric power at very high voltages, generally between 60,000 and 500,000 volts. It provides bulk transportation of electricity over long distances, usually from generating sources to substations for voltage reduction.
Transmission
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The ratio of the weight of a given volume of gas or vapor to the weight of an equal volume of air at the same temperature and pressure.
Less than 1 indicates ____________________?
Greater than 1 indicates ________________?
Vapor Density
Less than 1 indicates it is lighter than air and will rise
greater than 1 indicates heavier than air and will sink
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A space underground for electric cables, transformers, and other parts of the underground electric system.
Vault
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