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|What is amperage|
"Volt: The unit of measurement used to quantify electrical pressure or
the force that causes electrons to flow.|
Amp: the unit of measurement used to quantify the rate of electrical current.
Ohm: The unit of measurement used to quantify the opposition or “resistance” to the flow of electricity.
Watt: The unit of measurement used to quantify the rate or amount of electrical energy being used."
ampere is the current which one volt can send through a resistance of
Basic formula for electricity: Volts x amps = watts
Watts are combination of volts and amps.
Watts are total consumption of power by end user
Example: let's suppose:
Volts are the number of men who show up for work,
Amps are the effort of each man.
Watts are the amount of rock that must be produced to meet demand.
Men x effort = total output, or total amount of work.
Amperage is the heat behind electricity
Amperage is amount of work that can be done at a specific voltage.
Amperage causes fires. Control of heat from amperage is paramount for safe electricity.
|Volts and amps are inversely proportional ... which means if volts are increased, then amps are
And so the inverse is also true: If volts are decreased, then amps are increased.
If fewer men [volts] come to work, the average effort [amps] of each man must be increased to meet the demand for rock [watts]
When each man works harder, he sweats more because he is putting off more heat.
Same with amps. When amps increase, then heat increases.
Men work harder, they get hotter.
|Resistance R = watts ÷ amps
Resistance R of an element = rated volts squared ÷ rated watts
Resistance on a wire = resistivity of material used for wire x [length of wire ÷ cross sectional area of wire]
"One ohm is the resistance offered to the passage of one ampere when impelled by one volt"
All electrical wires and appliances consume energy. This energy is consumed.
Let's say resistance is the amount of energy each man consumes while working
When a man is working he is using energy. When you slam the pick downward, and it strikes the surface, that action consumes energy. When you lift the pick back into the air, that action consumes energy.
If work used up no energy, each man could work forever without rest
Let's say, the energy that each man consumes during work is equalivant to resistance on the electric wire.
|Control the heat, and you control amps||
The electric grid is based on controlling the heat caused by amps ...
Heat on the grid is controlled by:
1) keeping voltages uniform... and then making electric products that meet the uniform voltage.
2) using transformers to control the volt-amp relationship
3) using fuses and breakers that trip, and stop power, when heat exceeds rating
4) using correct wire size to meet the amp rating of fuse
|1) Uniform voltages help control heat from amps||
1) First step for controlling heat is done by keeping voltages uniform.
Uniform voltages help standardize the grid so peak loads on the grid can be calculated
Electric grids around the world offer specific voltages.
In the US, transmission and distribution lines carry high voltages such as 500,000 or 7200 volts.
Of course the end-user receives lower voltages. Lower voltages are necessary at end user because high voltage appliances are expensive to buy, hard to maintain, and very unsafe.
For example in the US, common end-user voltages are 120, 208, 240, 277, 440, 600 volts
Other parts of the world might offer 230 Volt or different volatges etc.
Products are made for these specific voltages. Generally, nobody offers products that are rated for 156 volts, because 156 volt electric service is not available.
Uniform voltages are first step for controlling heat from amps.
2) Transformers control volts and amps
Electric transmission lines are high voltage and low amperage
.... to reduce heat loss during transmission
Transformers are used control the volt-amp relationship.
Smaller power company tra nsformers are air cooled, while bigger transformers stay cool using special oils that are inside the transformer
Transformers are engineered to raise or lower the voltage, which causes higher or lower amps in same proportion.
When power company transmits electricity long distance, they use transformer located at generation plant to increase the voltage from 30,000 to 500,000 volts, etc.
When the transformer increases voltage, it also lowers amperage, so there is less heat-loss (or power loss) during transmission.
Long distance transmission of electric power requires low heat or low amperage, and this is accomplished by raising voltage..
If amps were allowed to be high, then long-distance transmission lines would be hotter, and much of the electric power would be consumed by heating the wire. Heat loss would reduce efficiency, reliability and decrease maximum distance for transmission.
Other transmission problems from high amps: hot wires would sag requiring closer transmission towers, and thus more towers, wires would be larger diameter and made of different materials, insulators would be more robust to hold the weight and withstand the heat. Cost of transmission would be higher if amps were higher.
Lowering heat loss by lowering amps and raising voltage allows long distance transmission of electricity. This applies to both AC transmission and HVDC (high voltage DC) transmission.
Long distance transmission wires travel to local substations. Transformers located at local distribution substations reduce the 500,000 volt transmission lines into lower voltages and higher amperage for shorter distance transmission to homes and businesses and other substations.
When electric power arrives at the end user location, more transformers are used to step down the voltage and increase amperage again.
For example a transformer located at typical US home might receive 7200 volt power line from the grid. The transformer converts 7200 volts into usable 240 Volt and 200 amp service for home.
Household low voltage and high amperage is transmitted very short distance from transformer to home.
Most high voltage transmission lines are bare wire suspended high above the ground.
Wires going to end user are sheathed with insulation.
Summary: Transformers can step up voltage, or step down voltage anywhere along the grid.
Step-up and step-down transformers are used to control the heat caused by amps. The use of transformers maximizes the efficiency of electric transmission.
Transformers are a method for controlling heat from amps.
|3) Fuses and circuit breakers trip when heat from amps exceeds rating||
3) Fuses and circuit breakers are used throughout the electrical grid to control heat from amperage
Each fuse and circuit breaker has specific amp rating
When too many amps are drawn across the wire, the wire gets hot.
Fuses and breakers respond to heat on the wire.
When heat exceeds amp rating, the fuse or breaker trips and stops flow of electric power.
All electric power that arrives at end user must have a fused breaker panel
Summary: To prevent overheated wire and resulting fire, the circuit breaker trips when heat on wire exceeds amp rating of fuse or breaker.
|4) Wire size must match amp rating or wire will overheat and cause fire||
4) Wire size is important for controlling heat from amps
Each wire in the electric grid is protected by a fuse or circuit breaker
Generally, the fuse protects full length of wire from too many amps
When heat on wire exceeds amp rating of fuse, the fuse trips before wire gets too hot
It is important that each wire match the amp rating of the fuse
If the wire is too small, or amp rating of fuse too large for wire size, then wire can overheat and cause melted wire, arcing and fire.
|AC or alternating current||The
electric grid is AC power.
AC is alternating current
AC is generated by rotating a magnet inside inside a magnetic field.
Each time the north and south pole of magnet rotate past a coil, the current reverses direction and flows opposite direction.
In the US, AC power reverses directions back and forth 60 times per second. This is because the generator rotates 60 times per second
When AC reverses direction, the electrons inside AC wires move back and forth
|AC and DC||
AC alternating current and DC direct current are two different types of electricity.
Both types of electricity cause electrons to move along surface of wire or other conductive material. If voltage is high enough using AC or DC, almost any material can conduct electricity.
DC is direct current.
Example: D-size lithium battery with + and - side. Or car battery produces 12 Volt DC. Or solar panel creates DC electricity and has + and - connections. Or use DC generator. Or convert AC electricity into DC using rectifier. Or convert DC into AC using inverter.
Electrons in DC power travel only one direction. They do not reverse direction like AC.
With DC power, electrons flow from positive to negative terminals. Or positive to ground.
Summary: With AC power, the electrons move back and forth 60 times per second. With DC power, the electrons move 1 direction, from positive to negative.
|Use DC to illustrate Volts||
We can use DC to demonstrate Volts.
If you put 3 D-size batteries end-to-end, or in series, the voltage is multiplied, but amps stay the same.
Each D battery is 1.5 volts so total voltage: 3 batteries x 1.5 volts = 4.5 volts.
|DC car battery to illustrate Amps||
We can use DC to demonstrate Amps.
Most people know a car battery is about 12 volt.... but why are battery wires so large in diameter?
Why are 12 volt car battery wires so much bigger in diameter than household wires that carry 120 volts to outlet?
Why are jumper cables so large diameter, when they just carry 12 volts?
The answer is amperage. Car batteries produce high amperage.
The big wire used for 12 volt car battery show that car batteries carry short burst of high amperage needed to start the car.
Unlike household 120 volt electricity which can kill you. The 12 volt car battery is not enough voltage to kill you.
Even 48 volt DC, commonly used in DC applications, is generally not enough to kill you. So 12-48 DC power is safe, compared with 120-240 volt AC or DC.
|DC car battery to illustrate heat from Amps||
Here is real-world example using car battery to show high heat from amperage
We know car batteries have a large wire so they can supply short burst of high amperage to the starter.
We can demonstrate heat using car jumper cables.
Jumper cables get stiff in the cold weather. But after you use the cables to jump another car, the cables are no longer stiff. Instead, the cables roll up easy because they got warm or hot carrying the amperage needed to start car.
We can also demonstrate need for correct wire size using car jumper cables.
The starter pull high amps. If jumper cables are not big enough in diameter, then you cannot get enough amps to jump the other car. Use larger cables, and the other car is more likely to start.
This example shows the heat from amps, and shows that wire size is important for carrying amps.
is wired in parallel
Appliances and loads rated for AC power are always wired in parallel
All household plugs and lights are wired in parallel
you wire AC in series instead of parallel,
you change voltage as it passes through each load, and that affects the
control of amps, and the performance of each load.
If two light bulbs are wired in series, then the voltage drops after the first light. The second light receives less voltage. The overall circuit is affected, and bulbs do not perform as expected.
You want all AC loads to receive equal voltage.
|AC generation produces
Three phase is transmitted over three separate hot wires: Hot 1, Hot 2, Hot 3
Each wire is rated for the amount of amps that it carries
To calculate wire size and transmission distance, total maximum load is calculated.
Higher wires shown in photo are the 3-phase distribution lines that run down the street. These lines are high voltage.
Lower wires are same voltage as distribution wires.
Lower wires are drop wires that cross the street and supply
3-phase power to Walgreen in Rosenberg Texas
Unseen in photograph are the 3 fuses that protect wires and transformers from over-amperage. Also unseen are the 3 transformers that convert high voltage into usable voltage for Walgreen. For example Walgreen might receive 240-480 Volt 3 phase that can be configured many different ways once inside the mechanical room and breaker panel.
Often when you see drop wires in this configuration, each drop wire is protected by a heat-rated fuse/ lightning arrestor. These drop wires do not have fuse because it is short distance over to Walgreen's service pole which has fuses.
|AC electric grid has bare
Connections can be made by tapping into a wire
Any bare wire carrying AC power can be tapped anywhere along the line, using another wire to distribute electricity many directions.
Often in other countries, a kunda line or hook is thrown over a bare wire to get free electricity. Absolutely this is not done without risk of death and the human body burned into carbon.
Illustration shows 3 hot wires located at top of pole, and three taps that send power into 3 lower wires.
Wires located highest on the pole come from generation side, arriving from nearby substation. Lower wires supply power to end user.
Note each wire is carefully separated from other wires.
Each wire is insulated away from the wooden pole. Insulators are made of specialized and purified glass. Without insulator, the wooden pole could become a conductor to ground, and catch fire, and disrupt integrity of power source.
It is important for the grid to maintain integrity of power.
AC power is a wave form. The 3 hot wires create a specific waveform. If the wave is disrupted, then clean power is not available at end user, causing malfunctions in electronics, overheated equipment, and inefficiencies that consume more power and cost more.
This illustration does not show the system neutral which is connected lower on pole, to which the ground wire is connected. All poles have ground wire.
3-phase electricity from generator to end user
From Singh's book on power generation
In alternating current systems - the volts and amperes might not be 100% synchronous, meaning that the oscillating waveform for volts is same as waveform for amps, so that amps do not lag volts
When synchronous the volt amperes equals the watts on a wattmeter
When not synchronous volt amperes exceed watts - reactive power
show need for high voltage, low amperage during transmission
|Transmission and practical cost factors||►Using basic formulas
above, the electric
company can determine correct wire diameter for each length of
transmssion, based on volts and amps, and based on choice of
available wire types and sizes.
►Economic costs are also important for calculating transmission of power.
Heavier wire costs more, so keeping voltage high means smaller diameter wire, which is less expensive than using bigger diameter wire.
However, if voltages are too high, then cost of switchgear and transformers goes up.
The mathematics of electricity must be balanced with economic costs.
►Cost for the end user is also important. High voltage appliances are imptactical because they are expensive and dangerous and hard to maintain. As a result, the electric company cannot deliver 500,000 volts to each home. The voltage must be stepped down at local substation transformers, and then stepped down again using transformer located at each end user to meet practical economics of end-user consumption.
30 31 alt 16 17
AC electrical devices are engineered to be wired in parallel,,,, so that voltage stays the same... and amperage is predictable...
120 volt 60 watt light bulb: watts divided by volts = .5 amp per bulb.
Ten bulbs wired in parallel.... each bulb receives uniform 120 volts and burns uniform 60 watt each.
Total amperage on line is 10 bulbs x .5 amp per bulb = 5 amps....
So amps are multiplied... and this lets the electrician know exactly which size breaker and wire are needed to prevent fire
If you connect appliances or water heaters differently than parallel ... then the uniformity of the electric grid is compromised, and the world will blow up as your electricians predicted.
Or more likely, catch fire.
course electricity does strange things but formulas that predict electric power do not vary by
The physics that govern electricity is generally uniform across the globe, but transmission and practical electric code vary by country.
What I know about international electric code came from guy in Costa Rica last year:
His electrician connected 18 gauge lamp cord directly to 100 amp main breaker
... ran the 18 gauge wire out of small hole in the box
... taped the wire to metal fence up to point where he spliced 18 gauge into 14 gauge wire coming from gate opener
... the splice was covered with black electric tape, and then taped directly to metal fence.
Tape appeared loose.
... additional photos showed #4 wires dropping down from transformer to feed 100 amp breaker.
... and then #4 wires leaving main breaker box and going to large house located several yards away
... main breaker box was hanging on metal fence using 2 u-bolts
...no ground wires were visible at the main breaker box ... maybe metal fence was the ground?
He wanted to know why smoke kept coming out of wall sockets in his home.
Answer: amperage overheating the wires, and wires were catching fire.
The #4 wires are too small for the 100 amp main breaker. When the #4 wire gets hot, it's not hot enough to trip 100 amp breaker, so more amperage is carried onto the wire than should be allowed. Breaker should be 70 amp so wire stays cool and will not carry too many amps.
The little 18 gauge lamp cord should never be connected to 100 amp breaker. If there was a short circuit on the line, 100 amps would turn that little wire into a light bulb filament and the wire would explode in a flash. That's a firecracker. But anybody standing nearby would be sprayed with liquid metal that would seriously burn or kill. Likewise, a person touching the metal fence could be injured or killed.
Adding 10 amp line fuse to a small wire might reduce the problem IF the wire was rated for 600 volts (lamp cord is not rated 600 volts), and If the wire and the splice were inside plastic conduit instead of taped to the metal fence, and IF the main box was grounded.
So why was smoke coming out of wall sockets? Inside the house was another breaker box, and all those breakers were too large for the wires, and each breaker served too many loads and appliances.
The 100 amp main breaker allowed too much amperage into the household breaker box, and the house was wired incorrectly and consuming too many amps for the electric service.
Wires were catching fire behind the walls, and smoke was coming out where electric outlets were located.
Did the house burn down? I don't know.
I am hoping the internet, and my website will help folks stay safe around the world.
How to match wire and breaker size
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