a conductive connection to the earth which acts as a protective measure
What are the three direct electrical injuries?
electrocution or death due to electrical shock
electrical shock
burns
What are 2 indirect electrical injuries?
falls
fires
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)
A/C current is
supplied by generators
distributed by above or underground power lines for end use in home, commercial and industrial application
DC current
supplied by batteries
batteries, UPS, vehicles are DC
Why does electricity travel?
There is a voltage difference between source (120 volts and return (0 volts/ground)
What is VAC?
____ volts alternating current
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
What is the relationship between voltage, current and resistance
V=IR
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
At what current level can a person experience painful shock and be unable to let go of wire
15-20 mA
Fust is rated by what measure?
The amount of current. Ampres.
Is grounding used for personal safety or machine integrity?
Groundings primary use is to prevent damage to facility and equipment
The Arc fault circuit interrupter works by...
by switches opening when the difference between the two currents (live and neutral) becomes too great
T/F - Switch and fuses primary purpose is to protect the people
False. Protect the machines
Inspecting voltage rated gloves in field requires:
visual inspection
inflation
reverse glove and repeat
Note: store in appropraite glove bag
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
Training for individuals dealing with electrical equipment must include:
safe work practices
isolation of electrical sources
test equipment
tools & PPE
Define watts:
quantity of electricity consumed. W = V x I
Define lockout:
procedure that prevents the release of hazardous energy
Define tagging:
Tells others that the device is locked out, who has locked it out and why
Good Rule: Safegaurds are needed when...
any machine part, function or process may cause injury
Major causes of machine accidents:
reaching to clear equipment
not using LO/TO
unauthorized person doing maintenance or operating