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sentpar
on FreezingBlue Flashcards.
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define currrent
the movement of electrical charge
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define resistance
opposition to current flow
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define voltage
a measure of electrical force
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define grounding
a conductive connection to the earth which acts as a protective measure
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What are the three direct electrical injuries?
- electrocution or death due to electrical shock
- electrical shock
- burns
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What are 2 indirect electrical injuries?
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In what situation can a bird get shocked?
When their wing span is large enough that they make contact with two lines (they fluctuate in voltage)
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A/C current is
- supplied by generators
- distributed by above or underground power lines for end use in home, commercial and industrial application
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DC current
- supplied by batteries
- batteries, UPS, vehicles are DC
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Why does electricity travel?
There is a voltage difference between source (120 volts and return (0 volts/ground)
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What is VAC?
____ volts alternating current
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Severity of shock is dependent on:
- path of current through the body
- amount of current flowing through the body (amps)
- Duration of shocking current through the body
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What is the relationship between voltage, current and resistance
V=IR
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these happen at what electrical currents?
death from Ventricular fibrillation if current pathway goes through heart & breathing difficulty due to muscular contraction
50-100 mA
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At what current level can a person experience painful shock and be unable to let go of wire
15-20 mA
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Fust is rated by what measure?
The amount of current. Ampres.
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Is grounding used for personal safety or machine integrity?
Groundings primary use is to prevent damage to facility and equipment
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The Arc fault circuit interrupter works by...
by switches opening when the difference between the two currents (live and neutral) becomes too great
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T/F - Switch and fuses primary purpose is to protect the people
False. Protect the machines
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Inspecting voltage rated gloves in field requires:
- visual inspection
- inflation
- reverse glove and repeat
- Note: store in appropraite glove bag
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Arc Flash/Blash occurs when...
Energized source comes in contact with a grounded source creating an unexpected release of energy in the form of noise and pressure
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Training for individuals dealing with electrical equipment must include:
- safe work practices
- isolation of electrical sources
- test equipment
- tools & PPE
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Define watts:
quantity of electricity consumed. W = V x I
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Define lockout:
procedure that prevents the release of hazardous energy
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Define tagging:
Tells others that the device is locked out, who has locked it out and why
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Good Rule: Safegaurds are needed when...
any machine part, function or process may cause injury
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Major causes of machine accidents:
- reaching to clear equipment
- not using LO/TO
- unauthorized person doing maintenance or operating
- missing or loose machine guards
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