Special Sub-Topic: Acronyms used in the Electrical Field
|What does AC and DC stand for in the electrical field?|
Alternating Current and Direct Current. Electricity is voltage and current. Voltage is electrical pressure, and current is the flow of charged particles. The difference between alternating current (AC) and direct current (DC) is that the electrons in an AC circuit regularly reverse their direction. In a DC circuit electrons always flow in the same direction.
|A 5,000 BTU air conditioner can efficiently cool up to 150 square feet or a 10 foot x 15 foot room. What does BTU stand for?
British Thermal Unit. British Thermal Unit (BTU) is a measure of heat energy. It is the amount of heat required to raise the temperature of one pound of water by one degree Fahrenheit.
A basic rule-of-thumb for selecting a room air conditioner is; 6,000 BTU unit for 200 square feet, 7,500 BTU unit for 300 square feet, and 10,000 BTU unit for 450 square feet.
|All receptacle outlets installed in bathrooms and in outdoor locations must be GFCI protected? What does GFCI stand for?|
Ground Fault Circuit Interrupter. Ground Fault Circuit Interrupter (GFCI)is an electrical device that can be either a circuit breaker or the receptacle outlet that is designed to protect a person from an accidental electrical shock or electrocution.
The basic theory of how a GFCI works is that the GFCI constantly monitors current flowing in a circuit. If the current path is altered, the GFCI quickly recognizes the change and turns off power to prevent a lethal dose of electricity.
|The purpose of the NEC is to protect people and property from hazards and dangers associated with the use of electricity. What does NEC mean?|
National Electrical Code. The National Electrical Code (NEC) is used as a guide by all electricial professionals in the US and sets the standards in the industry. The NEC was first published in 1897 and is revised and updated every three years to reflect current trends in the electrical industry.
|A number 12 AWG copper conductor can be placed and safely protected on a 20 amp circuit breaker. What does AWG mean?|
American Wire Gauge. Conductors "Wire" sizes used in the electrical industry use 3 different scales: AWG, Ought, and KCMIL. Conductors range from #14 AWG to 2000 KCMIL. American Wire Gauge (AWG) scale is the standard for smaller wires, #14,#12,#10,#8,#6,#4,#3,#2,#1 AWG. The "Ought" scale is the next larger wires, written as 1/0, 2/0, 3/0, & 4/0. The larger wires are identified by KCMIL which stands for one thousand circular mils. The standard sizes are; 250,300,350,400,500,600,700,800,900,1000,1250,1500,1750,2000 KCMIL.
|Motors are rated by their HP. What does HP stand for?|
Horsepower. Horsepower (HP) is the measure of the rate of doing work. In electricial terms, one horsepower is equal to 746 watts. In physical terms, one horsepower is equal to 550 foot-pounds per second, or 33,000 foot-pounds per minute.
The term horsepower was invented by the engineer/inventor James Watt. He wanted a way to talk about the power available from ponies, while using these animals in the coal mines to lift coal.
|Electricians use type AC/BX/MC cable in commercial and industrial buildings. What does AC stand for?|
Armored Cable. AC, BX, and MC are all flexible cables that have a jacket wrapped around the wire conductors forming an easily installable wiring system. Armored cable (AC) has a heavy armor-jacket that serves as an equipment ground. Metal-Clad Cable (MC) has an independent green conductor that serves as the grounding wire. BX cable is no longer manufactured because of it lacking a grounding conductor.
There are several stories about where the term BX came from; one being that "B" stands for the product line B and the "X" stands for experimental, because BX cable was invented by accident. Another story claims that it got its name from the town that it was discovered in, the "Bronx" New York. If you have a story or claim, please send it to me.
|Type UF cable is used in outdoor locations and can be buried directly in the ground. What does UF mean?|
Underground Feeder. Underground Feeder (UF) cable is listed for direct burial by UL standards. "Underwriters Laboratories" is an independent, not-for-profit product safety testing and certification organization. The jacket of UF cable is made of PVC (Polyvinyl Chloride) and is sunlight, moisture, and chemical resistant to protect the wire which can be buried without the need or use of conduit tubing.
Here are some other commonly used acronyms: "EMT" Electrical Metallic Tubing, "VD" Voltage Drop, "KVA" KiloVolt Amps, "IG" Isolated Ground, "OSHA" Occupational Safety & Health Administration, "RPM" Revolutions Per Minute, "IBEW" International Brotherhood of Electrical Workers, "EMF" ElectroMotive Force, "RMC" Rigid Metal Conduit, "WP" Weather Proof, "MDP" Main Distribution Panel, "CB" Circuit Breaker, "OCPD" OverCurrent Protection Device, "AHJ" Authority Having Jurisdiction, "BJ" Bonding Jumper.
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