To ground the electrical system to the earth.

Its is a return path for unused electrons to safely return to the earth.

The NEC calls it a Grounding Electrode. And defines it as: A conducting object through which a direct connection to earth is established.

 

When I was studying for my ham radio license I was taught that a ground rods job is to make sure all points of the system are at the same voltage potential.

 

Why is the electricity going into earth?

 

From Mike Holt: "Electrical power systems, such as the secondary winding of a transformer are grounded (connected to the earth) to limit the voltage induced by lightning, line surges, or unintentional contact by higher-voltage lines."

 

My understanding for a ground rod is for lighting and stray voltages, static. Will not save you from a fault.

 

You are correct. Generated electricity does not return to the earth because it didn't come from the earth , it returns to where it came from. Most of it will return on the conductors back to where it came from while a very small amount may travel through the earth back to where it came from. This amount will be determined by the resistance of the path and the earth is a very poor conductor so very little current will flow, never enough to clear a fault at the voltages we utilize. Just remember, any generated electrons that enter the earth must end up at their source, every single one of them. That is why it is called a circuit. No circuit, no electron flow. If you block the race track none of the race cars will make it back to the start line and they will simply stop moving.

 

Also, as to your question what is the real purpose of ground rods, in my opinion the real purpose is to make money for the manufacturers who have convinced us that they are necessary everywhere.

 

Well 'save you from a fault' is a pretty vague statement. Lots of different faults may occur over a period of time. Bottom a grounding electrode as part of a proper system plays many roles and does much more good than zero ground rods. If any one believes a properly placed ground rod serves no purpose then simply take the dayem thing loose and see how that works.

 

Ok, where does the electricity go, what pulls it in to the earth?

 

Electricity wants nothing to do with ground/earth it will always go back where it came from, the transformer through neutral. That’s why it’s very important to have it grounds bonded to neutral in the main panel or meter.

 

The rods do reduce some step potentials between the equipment and the earth you are standing on. I think this is why the push to use uffer in the footers.

 

So far it appears he asked a "question" that he already believes he has the answer for.

As a result, I'm puzzled by the reason for the question.

I agree. Not the most efficient way to start a conversation.

 

Ok, let’s say I have a electric motor with a fault to the frame on one of the hot legs and just a ground rod connected to the frame, not bonded. I go touch it am I live with electricity or am I safe?

 

If the ground rod is installed properly and the XO of the transformer is grounded the breaker will trip because all the current from the hot leg will flow to ground back to XO.

There are High Resistance Grounding systems in industrial manufacturing plants that connect the XO terminal ( center of the winding on the secondary side of the transformer) to ground through a large resistor that limits the current flow to ground in the case of a ground fault on a motor. This allows the motor to continue to run, even in a ground fault condition until repairs can be scheduled.

Here is a good link that explains it.

https://www.benderinc.com/know-how/technology/high-resistance-grounded-system-hrg

 

We have been over this before.

Just let it be. :cool2:

 

He who asked questions and knows of a answer still asks question to see other peoples view to try to under stand all possible out comes. But I guess he who asks questions is a bigger fool than he who doesn’t and pretending to know.

 

Most people start with something like "here is my understanding, am I missing anything?"

Way more efficient than questions, get answers, then telling what your understanding is.

 

He who uses search function on forum is wise man.

 

When a cow puts it's cute lil' nose to an electric fence wire, it discovers "ground":laugh:

During wet weather, the conductor (cow) is pretty efficient because the ground is wet. The earth around the ground rods is damp, and makes a good circuit. This is why you see cows wear rubber galoshes during wet spells...….ain't to keep their hoofies dry, it's to keep their nosies from gettin' shocked. They're smarter than ya think...…..

During hot, dry, weather...……….ya gotta have more ground rods.....dry earth doesn't make for good grounding. It also pays, during dry weather, to keep a few 5gal buckets of cubes in the back of the pickup so's ya can bring the cows back home when they just waltz thru the electric fence.

(P.S. ……………..I gave up on any kind of electric fencing about 2 decades ago )

 

1 Go to youtube
2 search for Mike Holt grounding and bonding
3 spend the next hour and a half listening to a really well presented explanation.
4 use your newfound knowledge for good.

 

Google?

Seite, just look on the opening page in this section on WW where he started a new thread.

 

Why do the 'ground' (bare) wires have to be seperate from the 'neutral' (generally white) wires now, when it used to be OK to connect them all together in the breaker panel?

 

Code says to bond ground and neutral together only on the first main disconnect, mainly because if there is a fault in the system the fault goes to the ground wire first then jumps over to neutral to the transformer. The only way it can do that is at the one bonded connection, if more than one connection the fault current could go threw other neutrals in the system and cause harm to what ever is hooked to the neutrals. Thats why the first connection is bonded, straight shot to the transformer. At least thats my understanding of it.

 

They still are at service entrance. New sub panels are sposed to be connected 4 wire, this allows the whites to remain insulated and keep currents off the ground system and chassis of machines.

 

First, polarization. Safety.

Second, ground fault whatever that is.

Third, revenue? I don't know about that one.

Fourth, referances point.

Polarization is .... Edit....

 

Just hearsay but at best about 12A at 120. Remember,,, only when it's part of a multi wire and carying unbalanced load is it acting as a neutral,, it's really a grounded conductor. A hot is an ungrounded conductor.

 

I wonder what effect the ground rod has on electrical noise, as grounding loops are a PIA in that sense. It's not just electrons flowing through the wires at play, though it mostly is.

 

They're great for antenna systems

 

the ground rod is to form a ground field and it has a designed electrical path to dissipate a static discharge voltage. BTW, I am suffering Static problem that damages my parts in my ways. So is everyone using an anti-static soldering mat or something like that?

 

I use wrist grounding straps. You can also take up smoking as the carbon from the smoke that gets on your fingers will help to bleed off the static charge. IBM learned this by accident. Techs that smoked had a lower failure rate of parts from ESD and they discovered that it was because the carbon in the smoke help to discharge any static from their body.

 

I think of cow barns. A traditional cow barn the cow is tethered to the stantions. Her water bowl is supplied by iron pipe. Vacuum, milk lines touch her. She stands on a urine soaked concrete floor. Behind her is a barn cleaner. All of these conductive surfaces is connected to a power supply. The definition separating earth grounding from bonding is a bit fuzzy. All of these machines are always wet with electrolyte. Any can contribute voltage.

If the current passes through a cow she suffers.

By connecting earth electrodes to concrete reinforcing steel to electrical neutral, along with bonding all conductive items in contact with the cow, current flows through these wires, instead of the cow.

Earth electrodes are notoriously high resistance. Still they provide a path of less resistance than a human being. Without them there would always be some small potential from center tap to ground.

 

Excellent point. Sometimes it's easier to put everything at the same potential rather than trying to insulate one from another. Ever notice inside a large electrical substation yard at the base of a manual disconnecting switch. There is a metal pad that is bonded to the support structure that the switch is mounted on. The operator of the switch stands on the metal pad effectively placing his body at the same potential as the switch. In the case of a short of the switch and the structure becomes energized, the operator is at the same potential so no current flows through his body and he is safe.