Chapter 2: Safety Flashcards
What is the difference between an electric shock and electrocution?
The length of exposure
NEC
National Electrical Code. A legal code published by the NFPA (National Fire Protection Agency).
AHJ
Authority Having Jurisdiction- An organization, office or individual responsible for enforcing requirements of a code or standard, or for approving equipment, materials, an installation or procedure.
OSHA
The Occupational Safety and Health Administration. Enforces code compliance & safety.
GFCI
Ground Fault Circuit Interrupter: trips the circuit when it detects over-current or a ground fault. It does this by measuring the voltage and current in the hot and neutral wires. Installed anywhere there is water or moisture (kitchen, bathroom, etc.).
Ground fault
An unwanted path to earth.
Grounding wire
Minimizes shock if you accidentally touch a live wire: the majority of the charge will go through the wire rather than your body, since positively charged electrons will always take the path of least resistance.
LOTO
Lock Out Tag Out (OSHA procedure)
AFCI
Arc-Fault Circuit Interrupter
NRTL
Nationally Recognized Testing Laboratory is an independent laboratory recognized by OSHA to test products to the specifications of applicable product safety standards
NFPA
National Fire Protection Association- publishes the NEC.
NIOSH
National Institute for Occupational Safety and Health
Class A fire
Common combustibles that burn to (A)sh - wood, paper, etc.
Class B fire
Flammable liquids - stored in a (B)arrel
Class C fire
(C)ircuit- energized electrical equipment
Class D fire
Flammable metals
Why do we handle wires with one hand when possible?
To prevent completing the circuit- the charge will go to the ground, decreasing risk of defibrillation.
What mainly determines the severity of a shock?
The amount of current.
What conditions affect the severity of a shock?
Body size, type of food you ate, humidity, clothing.
Electrical burn
A burn caused by contact with an electrical source, which allows an electrical current to pass through the body. The body heats up, causing internal burns.
Arc Flash
When electricity short-circuits through the air or across inadequate insulation
Arc blast
The explosion caused by an arc flash
What is the first rule of safety?
Think first.
PPE
Personal protective equipment
How do you safely use a straight ladder?
The distance from the base to the structure should be 1/4 of the height where the ladder touches the structure. If the top of the ladder is taller than the structure, there should be at least 3 feet/rungs extending beyond the point where the ladder touches the structure.
Scaffolds higher than — must have a guardrail.
10 feet.
Effects of 1 mA
Felt slightly as a tingle.
Effect of 1 mA to 10 mA
Muscles contract and prevent victim from releasing charged object.
Effect of 10 mA to 100 mA
Fatal after several seconds.
Effect of 100 mA or more
Almost always fatal
How do you ground a metal scaffold?
Connect a 2 AWG copper conductor between the scaffold and a ground-connecting fixture (such as a ground plate or ground rod).
What must you do before excavation?
Call 811 to have the underground utility lines marked.
Do not used powered excavating equipment within — of utility markings.
24 inches.
Trenches more than — deep must be reinforced to prevent the walls from caving in.
5 feet.
Lockout device
A safety device that prevents the energizing of a circuit by locking switches, breakers, valves, or enclosures
Tagout
The identification procedure that is used to let other workers know who applied a lockout.
Blockout device
Prevents a machine or appliance from automatically turning back on when power is restored.
Never — – — — unless absolutely necessary. Always – – – –!
Work on energized equipment. Turn the power off.
What is the procedure for helping a victim of electric shock?
(1) Call for help. (2) Turn off the power source. (3) If you can’t turn off the power immediately, remove the source of electric shock without touching the conductor or the victim. Use a wood stick or other nonconductive or insulated material to separate the conductor from the victim. (4) Talk to the victim in a loud and clear voice to see if they are conscious. (5) If the victim is not breathing, initiate CPR.
If you must work in wet conditions, how do you keep yourself safe?
(1) Use proper equipment, including insulated tools, PPE, and GFCI protection. (2) Turn the power off.
What kind of fumes are hazardous on a job site?
Flammable and non-flammable.
CPR
cardiopulmonary resuscitation
When you ground, you ground both the ____ and the _____.
Device; box
OCPD
Over current protective device (circuit breaker)
Branch circuit wires
Wires running between the circuit breaker and last connected device or receptacle
Feeder wires
Wires running from the service equipment or other power source (eg solar panel) to the main branch circuit over current device
Main breaker
Can cut off power to all other breakers
Transmission voltage
7200V
Residential voltage
120/240V
