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Why you need ground wire
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What does the ground do?
To people at home or workplace
, the purpose of ground wire is to protect people, circuits, and property from short circuits and possible fire by providing unobstructed path for electricity to reach earth. Less known, is that the ground also assists and protects the circuit breaker.
The ground functions as the direct pathway for Type 3 surge protectors, for example a surge protection strip on a computer will jump the gap to the ground wire when voltage on line exceeds rating. The ground wire is not connected to Type 1 and only indirectly connected to Type 2 surge protectors that absorb or suppress surge instead of redirecting surge to earth. However in event of massive surge overload, or lightning strike, the ground wire assists in minimizing damage from surge.

To the grid, the function of all the ground wires and ground rods at each home, building, pole, substation, transmission tower, all bonded together by the Neutral wire back to power plant, is to provide an array of earth connections that stabilize the electrical system by redirecting fire hazards, shorts, power surges from lightning, and high voltage events to earth .... basically the Neutral-ground array lets earth absorb stray voltage and 'balance the equation' so the grid can remain operable. Extreme overloads on transmission and distribution lines that exceed capacity of ground will cause breakers to trip at substation.
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Why you need ground wire
Electrocution: People get electrocuted, because they become the pathway for electricity to reach earth. Although it is not known exactly what electricity is, we can say that it has to do with charged electrons seeking to equalize the charge with other electrons. For example a static shock from rubbing feet across a carpet and touching a doorknob is caused by unequal charge. The electrons produced by friction of feet on carpet are equalizing with the charge of electrons on the doorknob. Of course the number of electrons is small so you are not harmed.
-The shock from a live electric wire is much larger than a static charge from carpet. The power plant generator rotates a magnet past coils of wire, and this causes electrons to come loose from their atomic orbits and flow down the wire. These electrons are charged. The earth likewise contains electrons that have a different charge than electrons on the wire. Read about electric generation As a result, electrons on the wire will follow any pathway to earth in an effort to equalize the charge. -Except the generator keeps pumping out charged electrons and if you become the pathway for all those electrons, it will kill you. That's the basis for electrocution, but doesn't cover all possible hazards.
-The ground wire helps reduce the risk of electrocution by offering a resistance-free path for electrons to reach earth. What is resistance? Imagine that charged electrons are like marbles, and resistance is a hill that surrounds the marbles and stops them from rolling away. If there is no resistance, the marbles are free to roll away. If there is some resistance, then the marbles can only roll away if the marbles get piled up so high that they spill over the top.
-A properly installed ground should have no resistance, while a person's body offers a fair amount of resistance, and so the ground wire becomes the easiest pathway for electrons to follow. In normal circumstances, if electrons are running wildly into the ground wire, the Hot wire supplying the source of electrons becomes overheated by all the electrons pouring down the wire, the circuit breaker detects the heat, and trips, cutting off the flow of electrons. However, the breaker will not trip immediately, so the ground wire and breaker cannot protect someone exposed to live electricity while standing in water or on bare soil or touching a grounded object such as clothes dryer or hull of a ship.
-Make sure to avoid hazards and install ground fault interrupter (GFCI) on any vulnerable circuit, such as bathroom, kitchen, and outdoor outlets, switches and equipment. The GFCI will immediately interpret the rush of electrons, just as they start to flow to earth, and cut off the circuit before the person gets killed.
GFCI devices need to be tested periodically and can fail, but usually fail in tripped position. Ground wires are permanent and do not need to be checked periodically at a home or business unless massive lightning strike melts the wire.
How to wire GFCI
What is electricity
Difference between surge and ground
Electric safety
-All voltages are dangerous. 120 volt is most common voltage for death from electrocution.
-When working on electric, always de-energize circuit. Wear tight clothes only. No loose clothes on sleeve, neck, legs, chest or abdominal areas. Remove metal from pockets, stand on dry boards.
-Remove jewelry rings watch metal before working on power. Always use non-conductive tools.  Use one hand when possible. Both hands give pathway for electricity to reach heart. Post warning signs. Do not reach into enclosures. Electric workbench should have insulated mat. Use insulated gloves. Equipment can have more than one power supply. Each box should be powered by one breaker, but sometimes not ... never assume power is off. Install safety switch within clear view of equipment. Make sure switch is in open or safety position before working on equipment. Protect power cords from sharp edges/ Replace worn power cords. Always cut power to tool that is jammed. Do not work on electricity with oxygen or other explosive vapors such as paint, gasoline, varnish. Close paint containers, store in separate, well-ventilated room. Note location of high voltage lines: Be cautions around incoming power lines when painting or tree trimming. Use insulated ladders. -Move indoors when lightning is within 1 mile.

-Oil, grease and carbon dust can accumulate on electronics and electrical equipment, producing potential hazard. Keep electrical equipment and electronics clean and covered. Be careful when soldering that extra solder does not drip on other parts causing potential short.

-Do not apply water to electrical fire. Use CO2 fire extinguisher Do not use foam fire extinguishers/ foam is conductive. Some electronic parts give off toxic fumes during fire. In event of fire, de-energize equipment, use CO2 extinguisher, ventilate room, avoid breathing smoke. Do not touch burned equipment with bare hands.

-Electrical dangers include death, injury, burns, falling down, getting hit by flying objects. During electrical shock, the muscles spasm causing person to clasp the electric device. Knock person loose with 2x4 or belt, rope, coat, blanket. Do not touch person or you will become electrified

-Person suffering from electric voltage shock: Lay them down. Keep from moving. Check if they are breathing. Continue artificial respiration. No stimulants or opiates because the heart might be affected by electric shock

-Electric burn can cause pain, shock, open wounds. Wash minor wounds with soap clean water apply cold water. Deep open bleeding wounds, use sterile compress, immediately call medial personnel.
Ground array/ Ground or earth loop
-Electricity is about charged electrons that are moving between unequal charges. When there is a short circuit or lightning strike, there are lots of electrons traveling on the ground wire going to the soil to equalize charge. A properly installed ground wire handles too many electrons by letting them pass freely. And so the effectiveness of ground is measured by how little resistance it offers to electrons.
-A ground is not a single ground rod. It is an array of thousands of ground rods that extend grid-wide. Just imagine how many grounds you pass each day. There is a ground rod at each pole, and each home and each business. Some installations have more than one point of grounding. All ground wires are bonded together by the Neutral wire all the way back to power company generator.
-A proper ground offers no resistance, but voltage irregularities on the grid have a background effect on ground wire resistance at each home and business. For example, if there is a lightning strike a few blocks away, even if the lightning does not strike the grid directly, it energizes the wires, causing a surge of electrons.
-The grid handles energized wires several ways, including surge protection, fuses, breakers and lightning arrestors, but the backstop that stabilizes the grid is the ground array. The excess electrons from a lightning strike are broadcast along the Neutral wire and into local ground rods. This in turn affects the resistance of the ground at your home because for a moment, the wire is crowded with electrons. The entire ground array is constantly pulsing with events that affect resistance. This is the effect of ground loop or earth loop which can cause a ground rod to have more resistance, and not work safely, especially if local soils are particularly resistant.
=The measurement and calculations for earth loop effect are complicated and best handled by specialized tool called earth ground clamp meter. See earth ground clamp meter
-If ground resistance is too high, because of earth loop or improper grounding, that can cause breakers to fail over time, and makes circuit beakers and appliances more vulnerable to surge events such as nearby lightning strike. Therefore the ground is important, not only for protecting equipment and living things, it also assists the circuit breaker.
-When a short circuit occurs, the overload should move rapidly through an unobstructed ground path and be absorbed in the earth via the ground rod. At the same moment, the breaker also absorbs the overload and trips. If the resistance is too high on the ground wire, that affects heat on the breaker and wire. This demonstrates that the ground wire assists the breaker. And of course the breaker is essential for protecting the grounding as well.
-This introduces the next point: the earth itself will offer resistance to the free flow of electrons: damp-dense-warm soils conduct better than dry-rocky-cold soils with frozen soil offering almost no conductivity. As a result, local codes for grounding vary by type of soil and local conditions, as does the need to test for earth loop effect.
Difference between surge and ground
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If your appliance has 3-prong grounded plug, then that appliance can have short circuit that travels to the outer shell of appliance, and this short can kill you if appliance is not grounded or you are exposed to live electricity while touching a grounded surface. That's why UL rated appliances and the national electric code are important. Many parts of the world have neither, although the importance of reliability is rapidly changing how the world treats its power grids.

The ground wire is connected to outer shell of appliance, and travels back to main breaker box, and then to ground rod outside home.

For example water heater recirculation pump has 3-prong plug. If recirculation pump gets a short circuit, then the ground wire will carry electricity safely away from pump, and away from water pipes.

If the ground fault is slight and not large, then breaker will NOT trip, and ground wire releases the small current into ground rod located outside house near main panel ... and it is generally safe to touch recirculation pump.

If the ground fault is large enough, it will begin to pull more current through shell of appliance and into ground wire and down to the ground rod, and that current will overheat wire at breaker, and breaker will trip. It will happen very quickly, but until breaker is tripped, the live current is available on the outer shell and can still kill you.

If you do not have ground wire, and recirculation pump has large short, the breaker won't trip, and if you touch recirculation pump with this condition while standing on bare ground, or while touching water pipe, or leaning into metal washing machine, or taking shower etc... you can fry like a fish, as electricity finds easiest path down to ground. This is why grounding is important.
IF you have GFCI or arc-fault breaker on the circuit, then the slightest ground will trip breaker before it becomes dangerous. GFCI is not a substitute for properly installed ground wire.
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Using water pipes for ground is unsafe and less-than-best-method.
In the past, it was common to use water pipe as the household ground rod by clamping main breaker panel ground to the  galvanized pipe. Generally the idea worked fine because outdoor water pipes are buried underground to prevent freezing, and normally long enough to offer zero resistance for grounding purposes.
Problems happen when stray current flows along the pipe. Even a trickle of current increases reactivity to rust and can accelerate deterioration of steel, most notably galvanized pipe and steel water heater tanks. Copper pipes do not deteriorate in same condition, but advent of plastic pipe makes the ground connection uncertain when water pipes are used.
Today, proper grounding requires ground rod or ground rod array that meets local soil conditions.

Ground wire for outdoor equipment
All outdoor pool and electric panels and solar installations must be grounded. Check local electric codes.
What does this mean? Drive ground rod 8-10 feet into soil or best to consult local code for grounding specs. Connect or 'Bond' #6 bare copper  or green-coated ground wire to ground rod and to solar panels and pipes on roof. Do the same for pool equipment, control panels and any outdoor subpanel.
Do NOT ground to water pipes. If electric system, antenna, or other metal is grounded to water pipes, then stray current corrosion can cause pipes to deteriorate. Also uncertain bond to ground because of plastic pipes. Always ground to a ground rod.
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Bond motor to ground Outdoor Pump or pump in wet location must be bonded to a ground wire that is connected to ground connected to the ground wire inside cable that comes from breaker box. Essentially this motor will have 2 grounds because the electrocution risk from outdoor equipment is high.

Ground all electrical devices, and make sure all household grounds are tied together and bonded to main breaker panel and to ground rod. Inspect outdoor ground rod to ensure proper connection of wire to rod. de-energize main breaker to work on ground rod.
Do not ground to water pipe: Make sure ground is connected to ground rod.
Water heaters and metal water pipes corrode with stray current corrosion.
Modern pex water lines and plastic pipe cannot be used as a ground.
When installing new water heater, water pipe, doing repairs on plumbing, installing new electric service etc... check that all electric is connected to dedicated ground wire that is bonded to outdoor ground rod
Bonded means the steel surface is directly connected to ground wire that is in turn connected to ground rod.
Outdoor control panel and pool pump must be bonded to ground wire that is connected to ground rod located at point of installation/ local codes vary so consult local electrician/ some codes may allow bonding to metal conduit that enters the soil at point of installation... but stray current corrosion can cause deterioration of this conduit/ codes vary for grounding for many reasons. Different soils offer different resistivity to grounding/ for example dense warm wet soils conduct to ground better than loose cold dry rocky soils.


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Bond solar panel to ground rod Bond all ground wires together in areas prone to lightning to help prevent lightning damage.
Bonding all grounds together will help prevent damage from lightning strikes beyond 100' away...
Strong lightning strikes within 100 feet must be handled by lightning rod. No system other than lightning rods will protect against direct lightning strike or strike within 100 feet.
Move indoors and do not stay on roof, or move metal ladders, or touch anything made of metal when lightning is within 1 mile or can be heard or seen.
Local code often requires bonding in areas with high incidence of lightning: this includes all ground rods for satellite, TV, phone, solar, electric panel, subpanels (within 100 feet) etc must be connected together and bonded to main electric panel ground rod driven into soil at correct depth to meet local code. Consult local electrician.
Codes for grounding depth vary: loose cold rocky dry soils are less conductive than dense warm wet soils. When soils are less conductive, the ground must be driven deeper or ground array installed to reduce impedance.
100' feet away for lighting is the rule of thumb.
Anything closer than 100', and nothing can protect against the voltage.
Beyond 100' and installing proper grounding can help redirect the surge into the ground.
Proper grounding requires all boxes and devices to be connected with a ground wire that is adequately connected to a ground rod that is at sufficient depth to reach permanently damp soil, or an array of ground rods with sufficient low resistance to meet local code, and that all grounds rods are bonded together with a common wire. For example if you have a ground rod for satellite TV and separate ground rod for electricity, they should be connected with a common ground wire of bare copper or green-coated copper wire.
However the ground wire will not protect electronics etc from damage from lightning ... for this you need a surge protector, suppressor, arrestor etc.
Note: surge protection wears out over time ... because it is consumed by the continuous small and large surge found in typical electric service.
surge vs ground block Surge vs ground
Generally all Type 3 surge protectors must be grounded. But grounding is not surge protection. Instead the Type 3 will 'jump the gap' to ground wire when surge is encountered.
Type 1 and 2 surge protectors are not grounded, and instead suppress or absorb overvoltages.
A ground wire will NOT protect equipment from overvoltage .... unless the power exceeds device rating or causes failure so that electricity arcs to the box and follows ground wire to ground rod.
Surge protection is needed to protect equipment from overvoltage.
For example motors will cause voltage spikes etc that can harm other appliances.
Type 1-2 surge protection suppresses or absorbs overvoltage and anomalies in electric power.. Type 3 surge protectors, found on co-ax and phone lines and surge protection strips are designed to put excess voltage in the ground wire. In some cases, with lightning strikes, the overvoltage is redirected to the ground wire. So overall the ground wire is a necessary part of surge protection, but is not required for Type 1-2 surge protector.
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Neutral and ground
Neutral and ground are bonded together at the service panel (breaker box) to provide safety and stabilization.
The neutral wire, or system neutral or service neutral wire runs throughout the electric grid ... from every home and business, across every pole, through every substation, back to the power plant... to 'stabilize' the entire grid.
The ground wire is bonded to the neutral at each step along the way. The ground protects each individual installation (pole, electric box, transformer etc) while the neutral 'stabilizes' the entire system. Both Neutral and ground are required.

Electricity always wants to flow back into the ground soil... and will do so with high speed and damaging effect if it lacks safeguards.
Neutral-ground system will safely route overvoltages or shorts to earth without arcing or bolts of electricity jumping from the hot wires to nearest object and causing fires and damage.
Since any material can conduct electricity if voltages are high enough, the Neutral-ground system is required to provide a quick and safe route to soil using ground wire, before voltages increase to point of arcing over to the nearest object.

By code... the neutral cannot be used as a ground... nor ground as a neutral... yet they are connected together.
As a general rule for household wiring... the neutral wire has to be as large as the hot wire... so the neutral wire can support the same amperage as the hot. While the ground wire can be smaller wire, for example incoming Hot and Neutral wires can be #2/0  but ground wire from the main service panel (breaker box) is usually smaller #6.
On a power pole the Neutral is always smaller than the Hot wire and the ground is smaller than the Neutral.

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Non-fusable safety switch required on outdoor installations, and high-voltage indoor applications such as 90 amp tankless electric water heater where breaker box not in plain sight of equipment.
fusable vrs non-fusable: Non-fusable means there is no breaker or fuse inside the cut-off box. Non fusable is manually-operated on-off switch for safety.
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