Will 120v To Ground Trip a Circuit Breaker?
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0:00 - 120v To Ground Intro
1:10 - Safety Precautions
1:57 - Setting Up Our Test
3:44 - Start Of First Test
4:57 - AFCI/GFCI Breakers
8:09 - Retest With Standard Breaker
10:59 - Voltage Gradients
14:40 - Conclusion
17:40 - SUBSCRIBE!!!
Will a ground fault to a copper ground rod trip a breaker? Does a ground rod get rid of voltage? What is the purpose of a ground rod? How sensitive are GFCI breakers? What happens when you short out 120v to the panel frame? These are some of the questions that this video may cause you to ponder. While we don't answer every question I do shed some light on what happens when you connect 120v directly to a ground rod and I demonstrate the voltage gradient that occurs in the soil around the grounding electrode.
Let me know if you have suggestions for more experiments that we should do in the future!
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Blessings from MN,
Ben
This reminds me of being a kid, going to this ungrounded light pole down the street. If you grabbed the light pole and the metal railing next to the pole it would electrocute you and you couldn't let go without some difficulty. Good times.
so the outside of the light pole was bonded to neutral?
💀💀 “good times”
Love this guy. He makes electrical knowledge so accessable. Such a fantastic teacher.
Something you did not mention, but I noticed you did. Under certain conditions (wet ground, raining) you should keep your feet together if you start to feel a shock. If your feet are at different distances from the gnd. rod or whatever, there most likely will be a dangerous voltage differencial between your feet and current will flow. This happened to me once. It was raining and I was walking towards a transformer down near the gnd. in the oilfield (touching nothing) when I started to feel my feet tingling, it became worse the closer I got. I stopped and put my feet together and it quit. So, I then jumped backwards and backed away. This was a higher voltage but it could still hurt you at 120 volts.
Damn. I am shocked how this video turned out. Electrifying content.
This man has a lot of potential!
agreed! he already changed MY life for real..bought a amp meter, because of him, and it's my new favorite tool! and for 15 bucks?? yeah, run it!
Oooooohhh. That's a bad pun.
I’m positive you’re right.
@@stroys7061 You're worse than he is.
Lester Marshall That’s kind of negative. I was trying to be positive. 😖
After years of KZhead, this is one of the most interesting videos. Thanks.
This brings to mind the "night-crawler hunting rig" that friend of my dad used more than 60 years ago. It consisted of two metal rods with lots of electrical tape wrapped around one end and sharpened on the other end. A long insulated copper wire went from one rod to a plug and another long insulated wire ran from the other rod to the other side of the same plug. He would drive one of the rods into the ground somewhere in the yard and then insert the plug into the socket. Then he would walk around the yard poking the "hot rod" into the ground until he found a soft spot where he would leave it for a few minutes. Eventually, night-crawlers would climb out of the ground and we would pick them up to go fishing the next day. As it turns out, the reason he was looking for a soft spot is that the rig worked best in slightly damp soil. Today I know how dangerous this was. Back then I can only remember an occasional "tingle" sometimes when picking the worms up off the damp ground. Your observation about the difference in voltage drop as the distance from the hot wire rod changes is evidence of the fact that ground is not a perfect conductor. A more familiar example is the power of lightning strikes and how a strike near a horse or cow standing on the ground causes them to get knocked over. Simply put, an animal with four feet on the ground experiences a potential (voltage) at one foot and a difference in potential at a different foot due to the resistance of the soil (earth) At the thousands of volts existing in lightning at the instant it strikes, each leg of the animal represents a separate parallel path for current to flow in addition to the path through the earth ground. This serves to remind us that lying on the ground during a lightning storm is exactly the wrong thing to do. The lightning does not have to be really close to do its damage to living things.
You have described what's known as step and touch potential. The ground acts as a resistor so the voltage varies along the path.
Hey, I did that as a kid, too, and lived to tell about it!
Also explains how two people in water can get different shock voltages - one stretched out in the water and one standing upright. It's the distance along the voltage differentials that get ya'
So I should stand on one foot during a lightning storm?
My neighbor lost two horses to a single lightning strike. Their bodies were found about 75 ft. In opposite directions from the tree that was blasted by the direct hit. The air in the lightning arc itself becomes a very good conductor during the instant the bolt occurs.
If you ever work at a campground where the owners did their own RV power boxes and did not bury the supply properly you find out very quickly that if you get a knick in the supply line you will find it quickly and painfully by just placing your hand on the ground close to the knick. Talk about a surprise when i went to sit down to work on a water line. It was a fast way to find a hidden knick in a power line but not one i hope to try again any time soon.
We found that out at the Ausable camp ground, I opened the fuse panel yes fuse panel they haven't updated their electric system, and I got a slight tingle it really wasn't bad then I hooked up my water line to the spigot and when I went to open my camper door I was knocked on my ass so my wife came running to see why I was on the ground she got nailed as well
@@supertrucker12916 yes, it happens, and they will check on a dry day and find no problems GFIC help this
Apprentice here. Excellent video! I just spent six hours studying ground and grounding rods and ground faults in NEC and tons of videos. One huge rabbit hole. I look forward to your series of videos.
Great video Ben. I work for a telephone company and we had a customer who's phone quit working. It was determined that the underground drop wire went bad. When the old wire was disconnected the customer came out of the house saying that his lights were going crazy. It ended up that his neutral was open and the unbalanced load was using the telephone wire sheath to get back to the transformer (probably why it went bad). If the ground rod was zero ohms back to the center tap of the transformer this would not have happened. Keep up the great videos.
Wow. That is super interesting. Thank you for sharing!
Ever held on to that 70v DC line when grandma makes a land line call its a shocking experience i tell ya
@Robert Lane, yes, it's ridiculous that home and power company grounds are of such poor quality that a communications ground has to take up the slack. In older houses, it's common to find the ground clamp disconnected from the earth ground (rod or water pipe), because the zinc-plated steel screws rusted away over the years! Obviously, ground clamps should come with non-ferrous screws. Here's another crazy thing: Faults between the power company transformer and the meter have no overcurrent protection and are DESIGNED to burn themselves clear! So, during Hurricane Sandy, a hot conductor on a pole touched an aerial ground wire and it didn't burn open. It just kept burning. Eventually a sheathed telephone cable of several hundred pair started burning as well as cable TV wires because they also shared the same ground. Someone went around to the utility poles nearby cutting the vertical ground wires running to earth which actually made the problem worse!
You've done an excellent job of showing what many electricians are unaware: the physical ground is an unacceptable bond. Grounding (the rod in the ground) is for power quality (and lightning protection). The earth acts like a giant capacitor, smoothing out voltage spikes. It is NOT the "source;" that would be the transformer. A side effect of this is there is potential between the ground and energized components. This is where bonding comes in. Bonding is electrically connecting non current-carrying metal components, plus the physical ground AND a leg of the electrical system (usually the neutral), so they are at the same voltage potential. Should a metal part (such as an enclosure) become energized by fault current, it prevents you from being shocked. The bond to the neutral is a low resistance path, creating an intentional short that will clear fault current by tripping the breaker, before you have a chance to be shocked The physical ground is NOT a low resistance path to the source that can be used instead of running a bonding wire, as this video shows. How? The NEC allows a maximum of 25 ohms earth resistance to the grounding electrode. Using Ohms Law we see current (I) equals voltage (V) divided by resistance (R). I = 120/25 = 4.8 amps. Definitely not enough to trip a standard breaker. This video should make it clear why driving in two grounding electrodes to the ground instead of using a physical bonding wire is useless for safety. This is why all outbuildings must be connected with a separate bond wire, in addition to needing a separate grounding electrode. This also shows the value of a GFCI. If current somehow leaks to ground that is not enough to overload the breaker, it will still save your life. Thank you for demonstrating this important fact.
Ben great video, I am a underground troubleshooter working for the utility company in NYC. Queens and Brooklyn. You would love to troubleshoot stray voltage in a underground network system. There are so many failure points, you do a great job in explaining and demonstrating the problems. Most people have no clue what the difference is between a ground and a neutral. If you opened the neutral to your home, the ground possibly pick up the amperage and you would have stray voltage all around your property. Especially on your hose spigots. 99% of flickering lights are due to open neutrals from utility, Great job, i subscribed today.
I can't imagine doing troubleshooting work underground in NYC! Would be super fun to come along with you to work and see what its like. Thanks for sharing!
The reason you current is increasing somewhat is due to the voltage breaking down the insulating property of the ground (it's actually quite conductive on its own but not completely conductive or insulative either). It's heating up the water in the ground as well causing it to become conductive. Also it's working on the basis of electrolysis which makes things more conductive as well.
So in the rain things would get interesting?
I'm amped AND VOLTED for this new series.
same
You’re grounded for using too many puns
So was Ben
Mike Holt would be proud. He was one of the first guys who posted a video doing this.
As a Water Utility worker. We are required to check for electrical voltage. The old school way was to ground the electrical system to the plumbing. I have been shocked when working on our water system. When we find the source we have the electrical company pull their meter and then they require them to get it fixed. Great video.
An excellent demonstration of step/touch potential. Excellent job.
As an FYI over-current breakers have 2 modes for tripping, one is a bimetalic strip that bends as it's heated by the current going through it, that pushes an actuator to trip the breaker. The other is a solenoid which triggers the trip mechanism immediately. The solenoid is tuned to trip at a higher current than what the breaker is labeled as. And the bimetalic strip is set to trip after a few minutes of rated current. So your short arc welding adventure will have drawn more current than 20A before the breaker tripped. The combo breakers use more sophisticated methods to detect the fault they are guarding in combination with the normal over-current detection.
Exactly. I want to take apart one of these dual function breakers and then see how it trips. If I'm careful enough maybe I can do so and keep it working! We shall see.
I watched several of Mike Holt's seminars, but there is nothing to replace the field work showing these principles in action. Great demo! What I was surprised at is the extremely low impedance of your ground system, only ~12 ohms. Clearly that's because the transformer ground is only a dozen feet away, and your earth must be very damp. Even the principle of 'ground' is a confusing misnomer. The earth is simply the least resistance connection back to the center pole of the transformer.
I too was surprised at the low impedance. I was expecting closer to 5 amps at most!
It depends on the distance from the ground rod, the humidity of soil, after rain breaker jumps instantly, mid swimmer sunny day mmm
+spelunkerd Actually MIke Hold did do that expirement, different details complements this video well:- kzhead.info/sun/jMtvd5mOjIWpink/bejne.html
I enjoy seeing other you tubers I subscribe to commenting on other subscribed channels. Really enjoy bens hvac and electrical videos and spelunkards dodge videos are the best on the web from an explanation standpoint. Two great content creators!
I believe in Canada the ground rod resistance has to be less that 5 ohms and less than 25 ohms in the U.S. But keep in mind that there are two ground rod resistances in series, the one for the main service panel and the other one at the transformer. What goes down into the ground must come back up. So the ground rod resistance in this case, which gave 10 amps of current, must have been 6 ohms + 6 ohms = 12 ohms total.
Ben - Keep on keepin' on with this stuff... pure gold!
Great video. It was a good visual representation of how a "bad earthing" is not really effective. For reference where I live the earhing resistance rating is required to be low enough to allow the circuit breaker to do its job .For example in your case you were getting around 12 Ohms which allows for only arround 10 Amps to "flow" to earth (120V / 12 Ohm = 10A). If you had for example a couple more rods connected to this one and got the resistance lower then 6 Ohms more electricity Amps(20+) will "flow" to earth and the thermal protection in the breaker will cut the power. Earhing is brilliant as a protection it just needs to be low enough to work with the intended breakers.
Thanks for clearing this up. Yeah I think he could pass the 20 amps and trip the breaker if the grounding rod was deeper or longer. I think the point is more than a high resistance grounding rod is not safe.
Ben, thanks again, interesting video. It would be worth your while having a read about substation grounding mats. These are critical to the safety of personnel working there. In fact, the normal setup is for the chain link fence to be grounded to this mat to prevent folks who touch the fence (unlock the gate for example) from being electrocuted from those earth voltage gradients that could be present in certain circumstances.
Interesting! I'll have to read about that for sure!
Things I knew, forgot and saw in practice. Very good video. Especially demonstrative for downed power lines.
Yo Benji! We appreciate the content and your style to teach us what your research has proved thus far. Your videos are enlightening. Thanks for the spark Cap!
Now you need to experiment with a SWER (Single Wire Earth Return) circuit. They use them for remote locations and also they were used for early rural electrification. Typically they used high voltages and a single steel conductor because the high tensile of the steel allowed larger spacing between poles. Low resistance grounding systems are key to making it work well so multipal rods and treatment around the rods with salt or other chemicals helps a lot. You'd be surprised at what you can power even at lower voltages like 120. Running a couple lights or small power tools is no problem
That sounds extremely interesting! I'll definitely keep that in mind for a future video!
You can even run a crystal radio with only an earth connection and no power whatsoever just from atmospheric capacitance.
Most all of rural Australia is SWER.
He delivered! There’s a SWER light bulb video on the channel now
As an amateur radio operator I fed a 70 ft. Ground mounted tower using a gamma match at the base. Antenna performance drastically improved when I pulled out the ground rod, dug a posthole about 4 ft. Backfilled with salted soil, and re-installed the ground rod right in the center of "the salt of the earth".
You're lining up to be one superb and high end electrician in the years to come. Greetings from Arizona. Oh yeah, please make a video about extracting worms.
Have to say, I am total blind and I bought the Home sense and had it installed and its helping me know what is useing all the power and so forth while moveing each line to the other breaker to take away from directly from the grid. Thanks for showing what would happen if I mess up and power go into ground. so I need to get a GFI breaker 240v breaker from the inverter so if a wire is wrong it trips. Thanks
Howdy. Absolutely wonderful clip. I admire your persistence. Highly regards.
Benjamin, Very good video! I will reference this when I see necessary to change someone's mind! About 99% of electricians and engineers incorrectly think it should trip. What I taught was, If you need worms to go fishing, get one of those 12" long nails, attach it to a wooden handle(like from a rake) solder a conductor to it up the handle and install a plug to it on the hot side. Now get an extension cord and plug it into a standard receptacle that you connect to the breaker in this video. Plug it in, and probe the ground in different places. Worms come very quickly out of the ground. Suggest you pull it out of the dirt before picking up the worms though! Respectfully, Kevin
No 99% of electricians and electrical engineer know the breaker will not trip. So here is why the breaker did not trip, the was no source back to the grounded conductor. When you drive a ground rod for a panel, a conductor is taken from the rod to the “neutral bar” or ground bar (I am setting this up as a first means of disconnect scenario and both the bars are bonded together) bounding the ground rod to the source power ground. Basically what I am saying, no path exists back to the source power ground because there is to much impedance in the earth to allow the electricity to flow freely from one ground rod to the other.
@@GUYJO1969 My point is, if you ask electricians and electrical designers and engineers this question 99% give an incorrect answer. Question, In a properly installed electrical system, if there is a short circuit between a hot conductor and the case of an electric heater that has equipment ground connected to it, from that point what is the path that the current will flow? Please give me your response to the question. I think you will get it correct. Respectfully, Kevin
@@KevinCoop1 It flows across the ground conductor to the grounding bar, and then to the neutral (technically the grounded conductor of the service) thus tripping the breaker. With respect, I am an electrician and I have always taught my apprentices that I’m order for a grounding system to work properly that all metallic parts that are not supposed to be energized must be “grounded” (I use that term loosely) or bonded (this is the proper term) together. I have never had, but one set of prints in which a grounding conductor did not return to the source neutral, it was for an IG system, I flatly refused to do it. With respect to you I have been an electrician for over 20 years, I do not know of any electrician or electrical engineer who insist that the entire system be bonded back.
It’s kinda insulting that you and you other people think so poorly of us as a trade. We try to train everyone the best we can. It’s very regrettable that you have ran into electricians that believe a ground rod driven into the ground and not tied into the source grounded conductor will trip a breaker. That is one of the first things I teach my apprentices. I had a friend shocked because the service neutral was lost at the pole and all the voltage and current was running down the grounding conductor to the ground rod. I can give you more details if you like.
I really like this video! I'm into structure cabling. Short to Ground will only the breaker of the Ground is bonded to Neutral( at the Main Panel)! I've seen engineers and electricians install 'isolalated ground' that does not connects the building grounding system at Main Panel.😱
* short to ground or any metal part would only work if at the breaker panel or first disconnect the current carrying conducter(neutral) is BONDED to ground.
A genuie thank you for allowing me to learn through your experiments!
Very interesting. Love it. That spark off the panel reminds me of years ago when I was working on my panel, I touched a wire to something and I bounced off a wall behind me. I paid a little better attention after that 😳
Holy shit when you stuck the probes in the ground I didn't expect that result!
this man is a full sender! hahah send it bro
Great instructional video, you have made this ground connected safety issue more easy to understand. Koodos!
Practical replication experimentation thanks for sharing good stuff love it.
Your Lastname Stahlstrom means Steel Electricity in german. So your name fits perfectly to the video
Its sahlstrom doe😂
It's actually an old Swedish name and the last part "Ström" does translates to "river" or "electricity.
@@bjornSE I know but his name is sahlstrom not sTahlstrom
@@bjornSE it just translates to directly to "steel current". Ström means current :)
2:31 "...without pre-twisting". You, sir, just broke the Internet.
Haha oops...
You don't need to pre-twist if you install wire nuts like you mean it. The wire nut itself will twist the wires as you install it. Keep going till you see a couple of twists on the insulated portion of the wire below the wire nut and you can be assured that what's inside the wire nut is twisted as well.
You do not need to pre-twist if your wire nut is listed for it. In other words the wire nut must be designed for non-twisted wire. I always twist because that's what I was taught when I was an apprentice. I think it gives a more reliable connection.
@@farmerdave7965 If the wire nut requires the wires to be pre-twisted the instructions will say so. I haven't run across any like that.
@@brianleeper5737 I totally agree! I have been in the trade for 25 years, I was never instructed to pre-twist the wires when I was an apprentice and I have never done it as a Journeyman. It is one of my pet peeves when I watch other Electricians from other States on KZhead. Quality wirenuts don't require it and Wagos(push-in connectors) don't require it obviously. It is just a waste of time. Russ from Oregon.
Southwest Missouri here, I really like all your videos. That was an exceptionally good experiment thank you
I love this guy. I saw his video 2 years ago and subscribed! Thank you for testing these electrical theories into objective reality
Im looking forward to this series. Very good video! Grounding rod from what im getting in my electrical apprentice journey is for lightning mainly. Its all about the current as those electrons get back to the source that trips a breaker so going to the grounding rod wouldn't do it. As for why that happens im still learning haha. I know bonding vs grounding is a confusing subject. But really grounding rods get too much focus.
Agreed.
An easy way to think of it is to look at a house as having two separate grounding systems which are for different purposes and are not functionally related to each other. The first grounding system uses the EGC (equipment grounding conductor) to provide a low impedance path back to the neutral bus bar to trip the breaker right away. The second grounding system simply connects the house's electrical system to the earth to allow accumulated static charges to go where they want and need to go - to the earth. Otherwise the static voltage can build up quite high on all of that wiring and short out expensive motors and things like that. Also it helps reduce high voltage spikes from nearby lighting strikes which also want to go to ground. So just look at this as two grounding systems with two different purposes which are not related. You could disconnect the earth ground and have no less safe an installation in the event of a hot wire touching the metal cabinet of an appliance, etc. The earth ground is not meant to help out in a situation like that, the ECG grounding system is entirely self sufficient in protecting from electrical shock due to cabinets becoming electrified.
@@MandrewP Great explanation!
Couple thoughts, When I have done ground resistance testing utilizing FOP method most single ground rods I’ve tested in dry soil have been around 10-25 ohms. These breakers have a long time and instantaneous trip elements. To hit the instantaneous region you are going to be somewhere around 10-15X the FLA rating otherwise you are in the time-over current region. Trying to measure fault current you may be better served by a meter that has a peak function as some meters are not “fast” enough to capture that instantaneous peak reading. Cool video!
I think the voltage step potential that you highlighted was cool. This is a big deal in high voltage substations where you can be dealing with thousands of volts step potential if equipment isn’t bonded thoroughly.
Great video; excited for the series! And you got me on the first test, ha--I didn't notice it was a DF breaker and answered "no" on the poll. Almost had an internal crisis when it tripped, lol. 14:38 - "That's wild. Ok, I'm going to go shut this off." Exactly what I was thinking as you were stepping around, ha. Stay safe!
That was my goal! ;) I too am looking forward to testing out various concepts in upcoming videos. There are a lot of good ideas in the comments of this video already!
Great video!! Another good reason why I subscribed!
So lucky to have a pole driver to set your ground rods. All I ever get is a bottle of water.
And a hacksaw....
USAV3T 😂😂😂🤣😂😂😂
@@marth6271 Eeek, say it a'int so, cutting grounding rods?!?! lol.
Why not just use a sledgehammer?
Depends on how well it connects to power station ground. Source ground. Earth ground is not the same as source ground. From the generator source.
First thing I thought of was the step potential from his proposed experiment, great to see he knew this and showed us the potential gradient. The understanding of this can take electricians/engineers years to grasp so great to see a young fella on the ball.
There where some horse killed in the UK at racing meet due to damaged hurried cable. Few years ago due to step potential people where fine due to the small step potential while the horses with their larger step potential where not
Great series idea , good luck and stay safe, Best wishes for all.
Mike Holt has great grounding and bonding info
Absolutely!
@@BenjaminSahlstrom Feels like you should've given Mike a little credit (or shout-out) here for all that you've learned in the past month. I saw your guys' exchange on the last video and like you I have learned a lot over the last month. :) Give him a shout out and I'll subscribe, making you my third subscription (I subscribe sparingly). Great video, though, great demonstrations and really nice production work making sure everything was visible. That one auto-focus shift right before the breaker trip was a gem, and I imagined you being delighted to discover it in editing. :) Questions and ideas for future videos (I've always been fascinated with Tesla's similar experiments): 1) What can you power with that earth to earth voltage differential? Perhaps two more ground rods with a load and measure the amps there? 2) This is AC going into the ground, is there any phase shift as you get further away from the ground rod? Perhaps a phase shift is affecting the voltage reading? (180 degrees out of phase would read 0.) 3) If you repeated this exact same experiment from the video with DC what would change? Again, great work! Really looking forward to your future videos!
@@WaddaFundraiser I actually did have this video in the works before I saw/found Mike's content but you're absolutely right that I should reference him more often! Maybe I'll add a card promoting one of his videos at the end of this one or add something in the description.
@@BenjaminSahlstrom I watch mikes videos. That guys is awesome bro
When the wire was touched to the metallic box, the current was far greater than 20 amps. The only limit on the current would be the impedance of the secondary winding of the utility transformer and the current probably peaked to 10K amps before the breaker tripped. That’’s why the wire melted. 20 amps should not have harmed the wire.
You are awesome brother. This morning I did the same and the results were just equeals. Woo
By the way. .ur main panel job u did at ur house is a work of art..excellent videos. Keep them coming.
Thanks!
Bonding is what makes everything safe!
Same with GFI but they to need be checked “ test button “
Perfect example of how downed power lines can be really dangerous
Great explaination and experiment. Have to check my grounding
Sounds like potentially a great series. Thanks!
I think that you are potentially correct currently! ;)
@@BenjaminSahlstrom in the same vein, one of our jokesters in my division on our aircraft carrier worked in the calibration lab. He had the paint shop make a large bold font sign for their door.... DANGER HIGH IMPEDANCE ! DO NOT ENTER !
Bro, the ground you just put in is a different ground from the one your panel is hooked up on. The soil has electrical resistance! This is exactly why there is one ground per service and only one! If instead of nailing a new ground, you just connect to the existing one, you would have a short immediately, just like you had when you sorted to your panel... Now, in a building with a good grounding there is less risk because metal in the building is good conductor, which would trip the breaker if touched by a hot wire. Great video, but I wish you'd explained it all better, the way you left it, makes it look like, in a correctly grounded system you are not safe.
That is the way of getting live worm bait "Night-crawlers" beware if it is wet or when it rains!!!
Interesting vid Benji ...
Another great video... very informative, a little drama, and easily digested by a “layman.” - thank you Ben!!
This isn't expert opinion. There are two ground systems in household electricity. The ground rod which provides a path for high voltage spikes induced by nearby lighting strikes, static from dry wind air flow, in big systems partial faults in motor windings and such. If the ground rod wasn't there then those spikes would build until they breached the insulation voltage rating and/or found an arc path to Earth. Uncontrolled arc paths are bad because they can happen right through or around flammable material. The high voltage spikes are high frequency and dissipate in the Earth resistance as they travel to the transmission system ground rod or the Earths static field. It can still have enough current to kill a puny human if they are part of the path. The safety ground is the bonding wire that connects every part that could become energized due to a hot wire fault, such as chassis, water and gas piping, etc, with a very low impedance path back to the transformer and then the breaker to clear the fault. You can still die in that split second it takes for the breaker to trip if your body makes the final connection. The bonding of the neutral to the system ground provides a path for the system spikes. The bonding of the safety ground to the neutral provides a path through the transformer to the breaker. The ground rod started out at 9 amps which is 13 ohms and increased, likely due to heating along the path in the Earth reducing resistance. 20 amps for the breaker is 6 ohms but you need lower resistance to cause an overcurrent fault or more time for a heating fault. The ground rod was interacting with the system ground of the box, the Earth provided a resistance between the test and system ground rods. When you touched the cabinet, you were interacting with the safety ground system, i.e., almost no resistance, high current to trip the breaker. The only way to get everything to the same potential is to use a low resistance connection, i.e., wire. And electricity takes all paths back to complete the circuit, including the ground rod if there is a path, not just the least resistance. The least resistance path gets the bulk of the parallel current.
Also, I'll say for better effectiveness, one system is more sensitive to resistance(ground to neutra path). The other is more sensitive to impedance due to the frequencies. That's why the ground conducter to the electrode must be short, straigh and with minimal bends as possible. Sharp bends increases the inductance significantly!
JK Brown why would a human being part of the path necessarily kill the human? Lightning strikes are one thing, but he is on a 120volt circuit. Would the electricity not travel along his skin as the easiest path and not close to his heart? Millivolts can kill your heart in close contact but it would be hard to get that close to the heart, given paths with less resistance. I have zapped myself plenty of times (120 and 240) with both of my hands completing a circuit and I am alive and well.
🤦🏻♂️
You'll trip the breaker if the ground stake is close enough to your panel's earth stake to allow more than 20A to flow. It's interesting to note that locally the earth has a fairly high resistance (as demonstrated by your voltage gradient) however because of the planet's size it has a low resistance because the area of the conductor is huge even though the conductivity of the ground is lower than a traditional conductor.
I wish someone can actually do it so I can "see" it. It's sometimes difficult for me to learn without tangible proof and I don't have enough safety equipment to try it at home haha. I might go boom!
Great video Benjamin.
Thank you for teaching Benjamin learning alot
You could have had some incandescent lights hooked to the live and various locations in the ground to demonstrate the voltage gradient.
Nice demonstration. The office I work at(though not right now) I have often noticed nightcrawlers coming out of the ground after it rained. I had assumed they came out either to escape the water or maybe due to disease. After the comments about nightcrawlers coming out after running a current through the ground, I have to wonder if there is some current from another source that is passinng through when the ground gets wet. When I am at the office next time, I may have to bring my multimeter with me and see if there is any voltage difference
You will likely find voltages.
Using a battery powered, ungrounded oscilloscope would be interesting. You may find RF currents in addition to power line AC frequency.
Your work is much appreciated
Cool demonstration.
Just a note, and I would actually like to see this tested if you have a meter that can test the actual short duration spike, but when you shorted that conductor to the housing and got that good arc that vaporized the conductor you were probably drawing more than 20 amps. Yes the breaker is rated to trip at twenty amps but they're mechanical devices and take a finite time to switch so for at least part of a cycle you could have been drawing consideriably more than 20 amps.
Could be 5-6 times that like 120A easy. It's like welding as you can see. The most dangerous moment in this vid, we are trusting the KA rating of the gfci breaker. And failing that a PSC of 1000s Amps is possible. Flash-over kills more electrician than electrocution does
@@Froggability yeah, single cycle arc currents can be huge.
My grandfather used to do this to get worms. He would dampen the ground then turn it on and wait for the worms to surface then turn it off and collect the worms.
Confused ...
@@uksds3806 why confused? This is a useful trick for fishing.
I've seen exterminators do this to drive moles to the surface. In other words, you may end up with your very own zoo bubbling up out of the ground around you! ;) WARNING: Don't do this at home. You are opening a can of worms (no pun intended) that could result in a person or pet being electrocuted. You are also making the dangerous assumption that the new grounding rod is a better ground than others in the area. Your current path could end up being dangerously different from what you expect.
Great experiment Ben .. Keep it up
Thank you so much Ben. Very clear explanation.
Did you measure the resistance of your earth rod ? It’s such a high resistance the MCB wouldn’t trip you would eventually start a fire 🔥 on the cable you would use your rcd for additional protection 👋 🇬🇧
Congratulations, you just built the first copper wire heating element. Welcome to the 19th century!
Yeah how hot did that rod get?
@@CrashCarson14 Actually it would be measurable with two thyristors in series. But that's another 5th grade physics class. LOL
Ben ! Thank you for your Video
These are awsome experiments. Thank you.
This is the reason that you shouldn't put your feet far apart in the event of a lightning strike. My aunt always told the story where lightning struck next to a cow. The poor animal had its legs wide apart and was killed by the current in the ground.
National Grid call it bunny hopping so voltage different between feet be very low. I can tell first hand you feel static electricity building up just before lighting strike
Thats the best way to learn. Do the things you should never do xD Let's connect ground rod to live wire and walk nearby ;D
my best Electricity classes and without paying Excelente video 👍
Very excellent video and desperately needed!
Years ago my male dog peed on a ground stake at the foot of a power pole and got a nasty shock. So guys watch where you pee.
Does that mean the ground rod has a poor connection to the earth, possibly due to corrosion? If the dog is grounded, and the rod is grounded, where is the shock potential?
@Pimp My Ditch Witch Myth-Busters showed this was dam near impossible - even using a high voltage fence shocker !
Guys, in Boston each winter there are few dogs that get electrocuted just walking on side walk from electric leakage from street light and salt does not help, you will see dogs with boots on feet, NO JOKE look it up like video Ben Add some salt water for city Folks
@@frankhynes4514 @R D P stated, his dog peed on a GROUND ROD. Did his dog tell him that it was shocking? Now, you are talking about HIGH VOLTAGE wires underground - Two completely different scenarios. Yes, HIGH VOLTAGE Power Wires are dangerous - everybody knows that ...
This is why you need to connect a metal outdoor stage at a festival to the panel ground and not just drive a ground rod and Earth it. That's what the utility here in Nova Scotia was calling for any metal outdoor stage has to have a ground rod down 8 feet and the stage connected to it. No other connections. So if a power cable shorts to the stage the breaker will not trip leaving the stage live to kill people. The utility actually thinks the ground rod will trip the breaker. scary! I have been wanting to do that test for a long time and show the utility the results.
That illustrates it perfectly. Crazy that this misconception still exists.
Yes, exactly.
@@BenjaminSahlstrom Especially among some engineers/electricians that install computer rooms and data centers! Once, I complained about that and the engineer removed from the project
They do that to prevent people from climbing onto the stage.🤣
@@Dreddip that works 👍
although I know the principle behind this topic it is still different when you see a live demonstration of it this is a perfect demonstration
Thank you for the educational content!
So how far from the gradient can you be and still energize a light bulb?
I sort of doubt that you'll get enough current from a multimeter probe to get enough current to light a bulb. Consider how much surface area a ground rod has compared to a multimeter probe. Then consider that the amount of surface area is proportional to the current flow. He should have tested the available current. Just because a meter says you have voltage doesn't mean that you have enough current available to do anything. These meters have very high input impedance.
As long as you have a sacrificial GFCI breaker, you should show what happens if the neutral wire is not installed. Or even if it is incorrectly connected to a ground wire ;)
facinating series. thank you. -C
Thanks for sharing this experiment. I used to think that the standard breaker (one cycle) will clear a ground fault through the earth, but I was terribly wrong. Now I should be more careful at work. Great experiment. God bless you.
I knew it wouldn't the breaker, but was suprized at the 10 amps. I wouldn't have thought 15ft of dirt would conduct that many amps.
soil has lots of conductive moisture in it
The earth has VERY low resistance but it is the connection to the earth that is hard to make low resistance.
@@MandrewP the us electrical code used to (maybe still is) require you to test your ground rod with an ohm meter, and if it was less than 8 (barely enough to trip a 15A breaker, and not anything larger) you installed another rod. The resistance to ground varies a lot with soil and moisture content even from one day to the next. Which is why local and national standards tend to prefer grounding plates and UFER grounds (buried in poured concrete foundations) these days. At least the electrode surface area is far larger...
To trip the 20 amp breaker the ground would have to be 6 ohms or less. Very few location have ground even close to that number.
Actually you would need 3 ohms or less - there are two ground rods in series - one going down into the ground and another on coming back up.
@@MandrewP He is saying less than 6 Ohms, as measured BETWEEN the two ground Rods ...
Dude, my curious mind has always wanted to do this but I never have. Thank you for sharing! The truth hertz!
Thank you for clarifying why ground wires are installed the way they specified to be done.
Would be interesting to see the current between points in the ground - or even see if you can power something from two ground spikes
Please Add ohms law into some of the conversation particularly with ground rod resistance
can we also talk about an infinite grid of resistors?
I regularly work with 12kV breakers. Thanks to this video I'm thinking I should open all breaker cabinets in class 2 gloves.
Interesting video Ben
When I watch the video, I feel like I'm in the Stone Age. As far as electrics are concerned, you are unbelievable light years behind in your country.
Oh whatever. Yeah, I'm sure you're so advanced you don't even use conductors anymore.
@@qball3835 Look at European Standarts and u will see !!!
@@DarkMatterGold1210 Actually the electrical systems used in Europe have more points of failure and result in a higher likelihood of injury or death. So your comment is completely false. Also, how can you say you are light years ahead when fewer than 5% of European households have air conditioning. You’re the ones who are still in the Stone Age.
Hey Mike...Can you expand your comment & include an example or two?? Tx
dantaniondb Not that I'm promoting Europe, but I've seen videos from Europe in which they talk about the superior safety features of European plugs and that Wago connectors are superior and used in Europe.
So I have been directed here from another video. Very interesting video and this somewhat goes against what I am used to. I'm a commercial electrician however and have never worked on anything smaller than a building with a 2,000 amp 277/480 delta Y service. In these buildings our grounding is rather substantial we bond almost every aspect of the building and the sheer amount of conductive mass connected to the panels is pretty extreme with everything being connected with typically a CAD welded #250 Bare ground wire as well as a Ufer ground, Delta Ground, Cold Water Ground, Building Steel Ground and of course Every other piece and aspect of the building are completely and totally connected (ignoring any IG's that may be present in the building). So I know my way around the Installation of larger electrical systems. NOW in this scenario, you are connecting your hot wire to earth directly but Your ground rod is not a part of your electrical system. I think It is worth pointing out that this is somewhat misleading... At your first means of disconnect for a separately derived system, you have to bond your Grounded conductor directly to your Grounding Conductor which then brings everything all together at your main switch whatever that may be. The reason I'm bringing this up is people may confuse that ground rod as the same thing as the GROUND in a building. It is in absolutely no way the same thing but I don't really think that was clear in this video. I also don't quite understand exactly what is going on here. I'm not certain but I suspect you are getting 9 amps through your circuit because even though you have no virtually no resistance on your circuit you are getting resistance between the ground rod for your experiment and the ground rod for your electrical system giving you X amps depending on how resistive the dirt is in that particular location using 120V. Would this same thing happen if your testing ground rod was in a theoretical void completely isolated from the rest of the earth but still driven into a similar mass? Thanks for reading if you bothered! and Thanks for replies in advanced if someone does happen to bother ;)
I bothered! Your experience with large electrical systems is impressive and I appreciate you taking the time to comment! You are correct of course that if the ground rod was part of my grounding system and thus connected to the main panel the circuit would have tripped. What I am trying to communicate is that just having a "ground rod" is not what makes a system safe. It's just as if not more important to make sure that every aspect of your grounding system is ultimately bonded to the neutral in the main panel. Thanks again for your comment and keep up the good work!
@@BenjaminSahlstrom Lets say that the neutral and ground cables are bonded toguether at the main panel. Now if a hot wire makes direct contact with the ground wire conductor What would happen? Does it cause a short circuit?
@@miguelac6872 yes.
@@BenjaminSahlstrom I am studying Level 1 electrical right now and the current subject is grounding. I've learned a lot from watching your videos. I was wondering if I could ask a question about your reply to the comment above, did I understand correctly, the 9 amps are flowing from the ground rod for your experiment to the ground rod for your electrical system? The 9 coulombs per second are not just flowing into the earth, never to be seen again?
@@davidstrens That is correct! Current is flowing from the ground rod I drove back to it's "source" which is the neutral/ground (since they are bonded) via the earth ground that is connected to my panel. Technically current could also be traveling back through other grounding electrodes throughout the electrical system wherever they are since they are also bonded to the neutral at some point.
Good video Benjamin! I had someone comment on one of my videos asking me this question and I replied saying that if it was a good ground with sufficiently low resistance, it would trip the breaker. He then pointed me to this video. Had I thought about it a little longer before answering I would have changed my mind. It reminded me of how my father and I got rid of dew worms in the lawn by placing 2 metal coat hangers in the ground about 3 feet apart and attaching them to hot and neutral. The breaker didn't trip, but the dew worms sure didn't like it and would come wriggling out of the ground almost immediately! Again, we must remind our viewers, "DON'T TRY THESE EXPERIMENTS YOURSELF" Way too much room for error! Step voltage and touch voltage can be very dangerous and deadly!
very interesting. good show!