Stick men
Keep wires and conduit straight
is a self-help site
Compare 16 ways to control gas and electric water heater Figure Volts Amps Watts for water heater How to wire tankless electric
How to install point of use water heater Point of use water heater
How to install gas water heater How to install electric water heater
How to install and troubleshoot garbage disposal Point of use water heater
How to maintain water heater Leaking water heater
Compare 16 electric and 3 gas water heater timers Troubleshoot Rheem tankless Clean sediment out of water heater 9 ways to save with water heater
How to install recirculation system Point of use water heater
How electric water heater works Troubleshoot electric water heater Troubleshoot gas water heater
Type 1 and type 2 surge protection surge protection
Search / all results
Search using Find button  

 Tweet button  

Formulas for Ohm's Law

Ohm's law

Ohm's law

Nobody can say exactly what electricity is.
We can describe what it does... it is the force that moves electrons across the surface of a conductor.
For example a copper wire is a conductor, and electricity can be used to move electrons down the wire.
When the electrons arrive at a light bulb, electricity pushes the electrons across a narrow filament inside the bulb.
The filament is also a type of wire, except smaller than regular electric wire.
When electrons are pushed across the small wire, the wire becomes hot, and begins to glow.
The glowing wire becomes the light from the light bulb.

How do we know what size wire and how much electricity is needed to cause the light bulb to give off light without also causing the larger wire to get hot?
That's where ohm's laws is used.
While we can't say exactly what electricity is, we can predict what it will do using ohm's law.
Ohm's laws are a series of formulas that help electricians and engineers design functional electrical and electronic systems. The basic formulas are shown in the ohms law wheel.

Ohms laws have been used in common practice for many decades.
Over time, reports arise about the peculiar things electricity can do... such as jump across wires and cause shorts and fires.
The practical experience over time, plus application of ohms laws has given rise to the National Electric Code.
The code is a guideline that standardizes wire and breaker sizes, and establishes best practices.
The practical application of ohm's law and the code lets electricians safely wire a house or a business.
If energy is applied to any atom, the electrons in orbit around the nucleus will jump to a higher state of energy.
Jumping to a higher state means the orbit of the electron is farther away from the nucleus.
When electrons are farther away from the nucleus, they become less bonded to the nucleus.
The nucleus has harder time keeping the electron in orbit.
With conductive materials, such as copper or silver, the electrons can become free from the nucleus with fairly low amount of energy applied to the conductor.
When electricity is applied to a copper or silver wire, the electrons begin jumping from one atom to the next atom.
They leave the orbit around one nucleus and jump to the orbit of the next nucleus. This dislodges the electron in that orbit And the cascade of atoms begins to flow down the wire.
Apply the correct amount of electricity to the correct size copper wire, and the flow of electrons becomes a useful tool for rotating motor, powering lights, and running a computer. Too much electricity, and things burn out. Too little electricity, and some circuits stop working while others can overheat.

Conductive materials have another interesting property
A power line for example. If lightning hits near a power line it will energize the wire.
This causes additional electrons to flow down the wire and is generally called a surge event.

The additional flow of electrons from a surge can knock out electric and electronic devices. Surge suppressors and arrestors help solve problem.
As a result, we know wires will absorb energy from nearby electrical source.

The same principle is used in a transformer. Transformers are basically two coils of wire located next to each other, each coil wrapped around a metal core and neither touching the other, with no shared wires in common.
Transformers are used to convert one voltage to another voltage. And according to Ohm's law, when voltage is changed, the amperage changes in inverse proportion.
There is an inverse relationship between volts and amps. The formula in ohms law is volts x amps = watts.
Transformers utilize this formula. Transformers convert high-volage low-amperage electricity into lower-voltage higher-ampeage electricity for end user.
So transformers will convert 7200 volt distribution electricity into 240 volt household electricity.

High-voltage wires arrive in your town and neighborhood from the power plant. These are transmission and distribution wires, and carry low amperage to reduce heat loss.
Low amperage is important for long distance transmission of electricity because high amperage causes heat loss on the wire, and reduces transmission distance.
To achieve low amperage, high voltage is necessary. Using Ohm's law, the correct voltage and amperage and wire diameter and distance of transmission can be calculated.
Resource: What is 3-phase electricity/ Power plant to end user

Once at your home, the high-voltage low-amperage wires enter a transformer. There is usually a transformer for each home or for each two homes. Inside the transformer are two coils of wire wrapped around an iron core, cooled by oil. The high voltage wires connect to one coil.
The wires going to your house connect to the other coil.
Resource: See inside main breaker box

When the high voltage coil is energized it produces an electric field that causes electrons to flow in both coils...
Only the high voltage coil receives electricity from the generator, but the flow of electrons through the high voltage coil will cause electrons to flow in the other coil.
Remeber the coils are not connected. they just sit next to each other. It is the same principle when a lightning strike causes a surge of electrons on the wire.

The reverse is also true.
In a electrical outage the high voltage line has no electricity. Local homeowner might connect a generator to thier breaker box to supply power to the refrigerator.
Electricity from the homeowner generator will travel to the transformer causing a flow of electrons that will energize the other coil that sends electricity into the 7200 volt line.
Of course the homeowner generator is not powerful enough to re-energize the grid. It may only cause a neighbor's light bulbs to burn slightly, but this electricity is dangerous for anybody trying to repair the outage. As a result a transfer switch is required when connecting a generator to your breaker box. Ot the homeowner could turn off main breaker to stop electricty from reaching transformer.

To review:
The high voltage wires are connected to a coil of wire that is wrapped around an iron core
And the wires going to your house are connected to a coil of wire wrapped around a iron core
Neither coil is connected to the other coil
Both coils are next to each other inside the transformer.
One coil will have more wraps around the iron core than the other coil. That is how the voltage is changed.
There are formulas that determine how many wraps each coil should have depending on the voltage and amperage ratio that is needed

Both coils have electrons that move when one of the two coils is energized

As a result the high-voltage coil will energize the lower voltage coil.

All transformers work the same.
For example phone charger is transformer.
When you plug in his cell phone transformer, 120 volts from the outlet is converted to a smaller voltage that is used to charge the battery in the cell phone
Basic electric book Volts = Amperes X Ohms
Amperes = Volts/Ohms
Ohms = Volts/Amperes
Watts = Volts X Amperes
Watts = (Volts X Volts) / Ohms
Watts = Amperes X Amperes X Ohms
Ohms = Watts / (Amperes X Amperes)
Best basic electric book
Electric book series

Basic electric book/ very detailed
House wiring

Resource: My simple illustrations and wiring:
Do it yourself electric
Email and I'll make illustration
Water heater formulas/ pdf
Water heater formulas 2/ pdf
Troubleshot household electricity
What is 3-phase
See inside household electricity
Basic home electricity
Figure volts amps watts
electric book Electric books: More trechnical
Linemans electric book
Power generation by Singh
3-phase power generation book at Amazon
Electric Power generation books at Amazon
3-phase wiring books at Amazon
circuit breaker

Circuit breakers

Water heater is tripping breaker
How to replace circuit breaker
How to wire gfci
Can AC breaker be used for DC breaker
How to reset circuit breaker
Not enough space for circuit breakers
Circuit breakers
How to install subpanel
Why you need ground wire
Match breaker and wire size
How to wire subpanel
See inside breaker box
How to wire safety switch
How to wire whole house surge protector
Question: Are both sides of the breaker 30 amp or one each one of them 15 amp ?

Answer: I had that discussion with a guy and did some research on electrician forums... which was a battle over sine waves and ultimately inconclusive.

Then I remembered reading an industry .pdf that said you can make a 240 breaker by combining 2 single-pole breakers, but that code requires you to install a 'common bar' between the breaker so if one trips, then the other breaker also trips...
Then I remembered the oscillating (sine wave) nature of electricity, where AC power reverses the direction of electrons 60 times per second... over and over and over... and how the voltage rises and falls as electrons come to a stop, reverse direction and accelerate the opposite direction... yet the average voltage is always above zero, and the oscillations happen so fast that it is not a noticeable factor for electricity as we humans use it.
Then I remembered that each leg of a 240 volt circuit is out-of-phase with the other leg.... which means the sine wave for one leg is mirror of the other leg... and the load receives more sustained power ...which is why we use 240 volt instead of 120 volts... because it is more efficient. This means each leg is delivering power to the load, and thus is independent of the other leg. Of course that is true because the electrons travel back and forth on the wire... and so one leg is pushing electrons when the other leg is pulling electrons ... this increasing total power, and this can be represented by the formula E = IR, or power (watts) = volts x amp. The formula shows if you have 30 amp, and change the voltage from 120 to 240, then the power (watts) goes up, or the amps (heat loss on wire) decreases.
... the final conclusion... the answer is that both breakers are 30 amp... because both are pushing and pulling electrons down the wire, like pedaling a bicycle with two legs instead of one.
... so yes... the answer is that both breakers are 30 amp.
Figure volts amps watts
Formulas for ohm's law
What is electricity
How a generator works

Basic household wiring
Basic water heater circuit

Figure volts amps watts for electric water heater
Test elements
Replace elements
How to wire tankless electric
How to change water heater temperature using timer
Change water heater from 240Volt to 120Volt
Replace thermostats
How to wire thermostats
How to wire water heater for off peak operation

How to twist wire
How to wire Cooper 277 pilot light switch
How to wire combo switch-outlet
How to replace 3-speed fan switch

How to wire dimmer
How to wire 3-way dimmer
How to wire occupancy switch
How to wire motion detector
How to wire TM811 and TM8111 switches
How to wire wall timers
How to wire box timers
How to wire off-delay timer
Wire off-delay timer
How to wire pin timers

How to wire and troubleshoot photo eyes
Reverse photoeye so it turns on in day
24 Volt photoeye
24 volt programmable timer

How to wire switches
How to add switch
How to add 3-way switch

Timer for 3-way switch
Timer for 4-way switch

How to add outlet 
How to wire 3-way switches
How to wire 4-way switches

Troubleshoot Malibu outdoor lights
Select and install wire connectors
Select wire size

Electrical formulas
Electricians forum

Electrical pages

How to wire arc fault breaker
How to wire GFCI
How to wire GFCI combo

Basic water heater circuit
How to wire water heater for 120Volt
Install old work box

How to drop wire from attic
Wire connector

How to wire 240volt outlets
How to install 3-phase timer
How to wire 3-phase outlets
How to wire 3-phase surge protector
What is 3-phase

How to wire whole house surge protector
How to wire under-counter water heater

See inside main breaker box
Replace breaker
Install subpanel

How to solder wires
Whole house surge protector
3-phase surge protection
Circuit breakers

Difference between 120 volt and 240 Volt
Difference between 50Hz and 60Hz
How to install electric meter on water heater
How to wire water heater thermostat
How to wire water heater with switches and timers

6x6x4 Enclosures
Intermatic timer enclosures

Read how to convert AC water heater to DC/ high voltage
Convert AC water heater to DC/ low voltage

How to wire DC solar water heater
DC relays for solar water heater
How to add another thermostat to water heater

How many Kwh to heat water
Chart for figuring heating time for electric heater
Additional Links

Flooded water heater

Leaking water heater

How to install gas water heater

Do it yourself water heater

Electricity from pole to breaker box

See basic 120V and 240V water heater circuits

How to twist wire
Cutler Hammer C25BUB230A
Solar water heater
9+ ways to save with water heater

Replace circuit breaker
How electric water heater works

How to install subpanel

How to wire off-peak water heater

Cost to operate gas and electric water heaters

Compare all water heater timers

Anode rods

Motorized shut off valve

Clean sediment from tank
Recirculation system
Hot water circulation system
Troubleshoot Rheem tankless
Troubleshoot Bosch tankless
Troubleshoot electric water heater
Troubleshoot gas water heater

How to wire 240Volt plugs and outlets

How to wire switches and plugs

More links
 EJ500 Utilitec WoodsWoods ST01C  ST01C ETW350 Aube T1032Aube
    Water heater GE  Leviton Hagar Westek TE06WHBWoods

Intermatic in-wall timers
Sylvania Intermatic EI500Intermatic Countdown
Intermatic parts
Intermatic trippers and parts
 Dayton Sprinkler timers Power pack
Wire T1906 and T1905 timers
Wire T-101 T103 T104 timers
Paragon timers and manuals
Tork TU universal timer
Westek box timers
Wire EH40 and WH40 timers
Tork timers and manuals
Tork TU universal timer
Troubleshoot Intermatic
Sylvania timers

How to set analog  timers
Pool timers and manuals
Intermatic T104P201
Wire GE 15207 timer
Intermatic GM series
Intermatic GM series
3-phase timer
3-phase timer

GE box timers
Gardena timers
Gardena T1030
Intermatic EH10 and WH21
Westinghouse timers
Westinghouse timers
Timex timers
Brinks timers

FVIR flammable vapor
Gas and electric water heaters Buy:
Industrial electric at Amazon

Industrial supplies at Amazon

Industrial and scientific Amazon
Shop Amazon - DEWALT
Shop Amazon - Black and Decker
Shop Amazon - Stanley Tools
Shop Amazon - SKIL Tools
Shop Amazon - Porter-Cable Tools
Shop Amazon - Bosch Tools
Shop Amazon saws and saw blades
box timers Compare box timers

Control water heater w/ Z-wave
Intermatic control centers Control centers:
+ manuals and parts

All control centers and parts

Including Z-wave
programmable timer Compare programmable timers

Control water heater with programmable wall timer timers Compare countdown timers

Control water heater with countdown timer
Low voltage power packs Low voltage transformers

Enter Amazon from my links

My response might end up in spam folder, check email folders
Privacy policy
Author page/ My Books