SOC Basic Electricity Flashcards
What is the purpose of panel boxes and breakers?
Divides an electrical power feed into subsidiary circuits, while providing a protective fuse.
- What color is used for neutral wire?
White
* if neutral wire is used as hot wire, recode with electrical tape
- What frequency is used outside of United States
50 Hz
- What is Watts?
The amount of energy consumed at a given point. It represented “W”
- What are some examples of circuit protection devices?
Fuses and Circuit Breakers
- What is bonding?
The permanent joining of metallic parts to form an electrically conducting path that ensures electrical continuity and the capacity to conduct safely any current likely to be imposed.
To establish an effective path for fault currentThe earth shall not be considered as an effective ground-fault current path
- What are some load sources?
Panel box
end of circuit receptacle
switch loop
junction box
- How deep grounding must be?
Must have 8 feet in ground, below the permanent moisture level
- What is Amperage?
The rate of electrical current flow. It represented “A”
- How to convert kilowatts to watt?
Kilowatt multiply by 1000.
1 kilowatts = 1000 watts
- Determine combined Amps
List all appliances, fixtures and their wattage, amps, kilowatts, volts, or horsepower (1hp=750w)
Add total wattage divide by 120/240 volts = Amps
Calculate for continuous load, i.e. 80% rule applies. • Examples, Total wattage is 17201720 /120 volts = 14.333 amps One 20 amp circuit
- What are the five factors influencing the effect of an electric current passing through a human body?
Frequency (60 hz is worst) Current frequency Voltage Body contact resistance Internal body resistance
- What are the main causes of Electrical Shock?
Wear and tear Defective construction Misuse of equipment Insulation failure (Insulation failure can result when the Hot ungrounded conductor on the appliance comes in contact with the metal frame of the appliance)
What are the signs of voltage drop?
Dimming lights Television pictures shrink Motors run hot Reduced heater output Improper appliance operation
- What is purpose of nail guard?
To prevent nail penetration directly into wires
- What are correct heights for the placement of various electrical boxes?
48” switch box
42” Receptacle over a counter
36” Washer/Dryer receptacle
12” Receptacle box in living area
- List some Electrical Safety Considerations
Wear rubber soled shoes
Use Fiberglass or wood ladders near electrical wires
Make sure the circuit is disconnected from its power source
Use proper circuit testers to ensure the circuit is dead
Treat all electrical circuits as live
Use fuse pullers for removing and replacing fuses
Avoid clothing with metal zippers or fasteners
Do not wear dog tags
Roll shirt sleeves down
- What are the two types of Electricity?
1) DC
Direct current, the electricity flowing in a constant direction.
Ex) Batteries, static and lightning
2) AC
Alternating current, the electricity repeatedly changes its direction.
Ex) Generator made, it’s a frequency measured in cycles per second, Hertz.
- What is the West Virginia Formula?
Watts = Voltage x Amps Volts = Watts / Amps Amps = Watts / Volts
- What is HP?
It is horsepower. One electrical horse power equals 750 watts.
- Describe typical usage for circuits based on amperage
20 amp: Small appliances and lighting
30 amp: Dryer, cook tops, and shall not exceed 80% of load
40-50 amp: Cooking equipment, electric ranges, water heaters
Over 50 amp: Electric furnaces, large heat pumps, air-conditioning equipment and larger loads
- What is Hertz?
A hertz is the measurement of electrical frequency, with 1 Hz being one cycle per second.
- What is Volts?
Voltage or volt is potential to do operate electric device
ie 110V
- What defines continuous load?
Maximum current expected to continue for three hours or more
- What are the parameters of a grounding rod?
Diameter 1/2 inch
No less than 8 feet in length
In ground at least 8 ft
Top flush with ground
- What calculation rule could you use for planning ?
Use 3 Watts per square foot
Examples, 2582 sq ft x 3 watts = 7746 watts 7746/120 = 64.55 amps 64.55x1.25 = 80.68 amps Can divide by smaller amps circuits to find how many
- What is Ohm’s law?
It defines the relationships between: (P) Power (E) Voltage (I) Current (R) Resistance
- What are the three different sizes of main panel box?
100, 150, 200 AMPS