Ground Rod Demonstration

[Weaton325]

Hello,

I would like to preform a demonstration for my class for our grounding and bonding section. I am curious if anyone has taken a ground rod , separate from the buildings grounding system, and hooked it to 120V(off a breaker). This was mentioned in Mike Holts grounding and bonding myths lesson. I am using this is illustrate the concept of current using the ground to complete a circuit . I want to know if anyone has done this and what safety protocols you put in place to ensure the experiment was conducted safely .

Thanks.

 

[Little Bill]

Here is a video that Mike Holt made on ground rods.

 

[infinity]

Hello,

I would like to preform a demonstration for my class for our grounding and bonding section. I am curious if anyone has taken a ground rod , separate from the buildings grounding system, and hooked it to 120V(off a breaker). This was mentioned in Mike Holts grounding and bonding myths lesson. I am using this is illustrate the concept of current using the ground to complete a circuit . I want to know if anyone has done this and what safety protocols you put in place to ensure the experiment was conducted safely .

Thanks.

Do not do this (OK I did try it in my own house). Hooked the GEC from the rod directly to a 20 amp breaker and turned it in. If I remember correctly when I measured current with an Amprobe it read 4 amps.

 

[Adamjamma]

Hmm... have me wondering if I run three ground rods..l hook live to one, ground pin to two, neutral to three, and they are four feet apart... then run this to an RCD... how long before the circuit tripped, or even would it? Hmmm... maybe one day...

 

[gadfly56]

Hmm... have me wondering if I run three ground rods..l hook live to one, ground pin to two, neutral to three, and they are four feet apart... then run this to an RCD... how long before the circuit tripped, or even would it? Hmmm... maybe one day...

Pretty close to "never", or thereabouts. See the video that Little Bill linked to. Eventually they drive the ground rod down to about 50 feet IIRC and the resistance was still about 13 ohms or some such, not low enough to clear a fault at the panel.

 

[just the cowboy]

use a fence charger

use a fence charger

A controlled way to do it is with a electric fence charger, current is limited. They make small ones for dogs cheaper and less distance.

Hook up the charger as shown in manual.
Using insulated gate handle and insulated wire made for chargers, hold handle 1" give or take from rod. Nice white/blue arc and snap.
Now repeat at 1 foot intervals useing the dirt or grass. Arc will get smaller and less pop.

Cowboy

 

[jwelectric]

Use Ohm’s law to demonstrate, E=IxR
120 volts divided by 25 ohms equals 4.8 amps

 

[Tony S]

Do not do this (OK I did try it in my own house). Hooked the GEC from the rod directly to a 20 amp breaker and turned it in. If I remember correctly when I measured current with an Amprobe it read 4 amps.

Similar to the method I used on my own house except I put an old 2kW 250V heater element in line. I got the full 8A flowing in to the earth electrode.

OK I cheated a bit with the earth electrode. I had to dig out all of the drains to replace the piping and so ran a copper tape alongside the new pipe. Digging out a new drain chamber I found a redundant gas main, so I brazed a stud to it.

Deep driven rods in North Derbyshire UK you haven’t a chance without drilling. I’d got a 600 Ft shallow earth electrode for more or less for nothing.

 

[gadfly56]

Similar to the method I used on my own house except I put an old 2kW 250V heater element in line. I got the full 8A flowing in to the earth electrode.

OK I cheated a bit with the earth electrode. I had to dig out all of the drains to replace the piping and so ran a copper tape alongside the new pipe. Digging out a new drain chamber I found a redundant gas main, so I brazed a stud to it.

Deep driven rods in North Derbyshire UK you haven’t a chance without drilling. I’d got a 600 Ft shallow earth electrode for more or less for nothing.

How did you know it was redundant? Finding out otherwise could have been an...uplifting experience.

 

[zog]

This is an oldie but a goodie, go to about 5 minute mark for some ground rod tests

https://www.youtube.com/watch?v=hG2p9N1MHlk

 

[jaggedben]

Pretty close to "never", or thereabouts. See the video that Little Bill linked to. Eventually they drive the ground rod down to about 50 feet IIRC and the resistance was still about 13 ohms or some such, not low enough to clear a fault at the panel.

Note he said RCD. Not overcurrent device. Kinda off topic though.

 

[gadfly56]

Note he said RCD. Not overcurrent device. Kinda off topic though.

You're right, my eyes just kind of skipped over the "RCD" part. I should have looked that up.

 

[Galt]

I hate to say this but we do it to get night crawlers to the surface for fish bait.

 

[ptonsparky]

I hate to say this but we do it to get night crawlers to the surface for fish bait.

My Dad did it too. He made us stand on the porch, then let us come out after he disconnected.

I also remember the wiring he did in the house.

 

[jumper]

I also remember the wiring he did in the house.

Hmmm, as in “he was good”; or “well, it worked”.

 

[ptonsparky]

Hmmm, as in “he was good”; or “well, it worked”.

We lived, and no fires. That’s a measure of success, right?

 

[jumper]

We lived, and no fires. That’s a measure of success, right?

Hell yeah!:thumbsup:

 

[Tony S]

How did you know it was redundant? Finding out otherwise could have been an...uplifting experience.

I put a hacksaw through it otherwise the capped end would have been in the middle of the new chamber.

 

[Ingenieur]

Hmm... have me wondering if I run three ground rods..l hook live to one, ground pin to two, neutral to three, and they are four feet apart... then run this to an RCD... how long before the circuit tripped, or even would it? Hmmm... maybe one day...

try this
2 rods at 10' apart, 2' deep
hot to one from a cb, the lower the better
neut to the other
amp clamp on the supply
use a plug so you can disconnect when moving the rod

start moving the neut rod further away in increments of 5' foot
record current, you know v= 120, so therefor R

better yet do this with proper gnd R tester

 

[Adamjamma]

Am saving this for the banana field behind my home... see if the various Mark section make a difference ... will let you know in a few years when I get to experiment..lol...