ITEC 271 Final Flashcards
Electrical safety problems
Fires, burns, and death
Death can occur in two ways
Direct (electrocution) and indirect (falls)
Causes of electrical safety problems
Lack of knowledge, can’t see it, one of the most common in construction
9 -10 house fires are what kind of fires
Electrical fires
Voltage represents
Volts - electromotive force
Current represents
Amps - intensity
Resistance represents
Ohms - resistance
Is current or voltage the killer
Current is the killer
Electrical system comparison to a water system
Voltage = pressure (P.S.I), current = Quantity (G.P.M.), and resistance = nozzle on the hose
Define conductor
Carry electricity
Define Insulator
Does not carry electricity (high resistance)
Define circuit
Must be complete path for current to travel in
5 factors affecting extent of harm
- Amount of current (amps) 2. Path of current 3. Length of time 4. “Grounding” can eliminate the problem
Path of current characteristics
Finger to finger = minimal hazard and arm to arm/arm to leg = heart muscles being affected
Length of time characteristics
1-2 seconds can cause the heart harm, remove victim from the source, remove source from the victim, DO NOT touch the victim (use a stick), and begin CPR
A ground example
3-prong adapter
Current through a resistance generates what
Heat (internal burns)
Turn off power at
Switch box or fuse box
Capacitors perform what function
Store current
How man hands should be used when replacing fuses
1 hand, use rubber mats, and insulated tools (fuse pullers)
Rings and watches are considered what `
Conductors
Prevention characteristics
All wiring should be to N.E.C. standard, plug items direct (no extension cords), observe insulation on wire, lock fuse boxes during repair, and grasp plug, not cord
The longer the extension cord……
The larger the wire (no insulation)
Plugs are the most common what
Problem
Which side of an outlet is the hot side
The smaller slot that is represented by gold screws
Which color wire attaches to the hot side
Black wire
What wire connects to the silver screws of the larger slot
White wire
A 3-way switch might have this type of wire
Common wire
Ceramic fixture characteristics
It does not matter where you hook the white and black wires
Limn Pliers characteristics
Used to cut romex and sheath wiring
Wire stripper characteristics
Used to strip romex and contain labeling for exact wire gauge
Electrical box characteristics
Round boxes are used for lighting fixtures and a square boxes are used for switches or outlets
How does DC current flow
In one direction
Types of AC current
Single-phase and three phase
Single-phase is used in what apps
Residential apps
Three phase occurs every
60th of a second (pushing of electricity)
120 volts
15, 20 amps, wire size 14, 12
15 A operates
Lights
20 A operates
kitchen
240 Volts
30, 40, 50 A and wire size 10, 8, 6
30 A operates
Stove
40 A operates
Water heater
50 A operates
Dryer
480 Volts
Wire size 4, 2, 0, 00, 000, 0000
