What is the purpose of panel boxes and breakers?
Divides an electrical power feed into subsidiary circuits, while providing a protective fuse.
White
* if neutral wire is used as hot wire, recode with electrical tape
50 Hz
The amount of energy consumed at a given point. It represented “W”
Fuses and Circuit Breakers
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
Panel box
end of circuit receptacle
switch loop
junction box
Must have 8 feet in ground, below the permanent moisture level
The rate of electrical current flow. It represented “A”
Kilowatt multiply by 1000.
1 kilowatts = 1000 watts
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
Frequency (60 hz is worst) Current frequency Voltage Body contact resistance Internal body resistance
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
To prevent nail penetration directly into wires
48” switch box
42” Receptacle over a counter
36” Washer/Dryer receptacle
12” Receptacle box in living area
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
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.
Watts = Voltage x Amps Volts = Watts / Amps Amps = Watts / Volts
It is horsepower. One electrical horse power equals 750 watts.
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
A hertz is the measurement of electrical frequency, with 1 Hz being one cycle per second.
Voltage or volt is potential to do operate electric device
ie 110V
Maximum current expected to continue for three hours or more