Tools are Grounded to Send the surge of electricty to earth

tom baker

First Chief Moderator
Staff member
Watch this U-tube video https://www.youtube.com/watch?v=A9KSGAnjo2U, at about 5 minutes you'll find out that tools have a separate grounding conductor connected to earth, so if there is a short circuit, it sends the surge of electricity to earth instead of the person.
It was posted by Joe Tedesco, and I would think he would know better. The comments state how good a video this is. I will use it in my introduction to 100 Essential Rules of the NEC, and the many service personnel who died in Iraq/Afghanistan due to improper grounding and bonding
 

user 100

Senior Member
Location
texas
Watch this U-tube video https://www.youtube.com/watch?v=A9KSGAnjo2U, at about 5 minutes you'll find out that tools have a separate grounding conductor connected to earth, so if there is a short circuit, it sends the surge of electricity to earth instead of the person.
It was posted by Joe Tedesco, and I would think he would know better. The comments state how good a video this is. I will use it in my introduction to 100 Essential Rules of the NEC, and the many service personnel who died in Iraq/Afghanistan due to improper grounding and bonding
This has to be some kind of a joke- the dorky guy w/the glasses looks like one of the marx bros.
That gal towards the end did good w/ the board though.:)

Current will try to return to the source thru soil, but the impedance of that earth path will almost never be low enough to allow enough current to open an ocpd and prevent electrocution. The resistance of that fault path is key- you want it as low as possible, and your going to get close to that with a hard connection back to the source, not some rod jammed 8ft in soil.

It's a shame "the grounding to the earth saves lives" myth continues to be propagated.:happyno:
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Electrical Contractor
So if there is a short to the casing of a grounded tool where do you think the current goes? I don't understand the issue... The equipment grounding conductor is connected back to the earth but I understand that is not what opens the overcurrent protective device. This video is not for electricians as it states in the beginning so I guess they took took some leniency in the answer. I didn't find it so bad
 

kwired

Electron manager
Location
NE Nebraska
We don't need to dumb it down for non electricians, this gives them a false sense of security and promotes them to think they know what they are doing. Tell them how it is, then if they still think they what they are doing at least they were informed correctly. Equipment grounding is to let fault current return to it's source not to earth, earth may or may not end up being a portion of that path, but is almost never the sole path (not an effective fault clearing path anyhow) for less then 1000 volts. It also is there to attempt to put non current carrying objects at same potential as earth - during non fault conditions.
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Electrical Contractor
We don't need to dumb it down for non electricians, this gives them a false sense of security and promotes them to think they know what they are doing. Tell them how it is, then if they still think they what they are doing at least they were informed correctly. Equipment grounding is to let fault current return to it's source not to earth, earth may or may not end up being a portion of that path, but is almost never the sole path (not an effective fault clearing path anyhow) for less then 1000 volts. It also is there to attempt to put non current carrying objects at same potential as earth - during non fault conditions.

I disagree--
 

user 100

Senior Member
Location
texas
We don't need to dumb it down for non electricians, this gives them a false sense of security and promotes them to think they know what they are doing. Tell them how it is, then if they still think they what they are doing at least they were informed correctly. Equipment grounding is to let fault current return to it's source not to earth, earth may or may not end up being a portion of that path, but is almost never the sole path (not an effective fault clearing path anyhow) for less then 1000 volts. It also is there to attempt to put non current carrying objects at same potential as earth - during non fault conditions.
And what you put there isn't an overly technical "Hawking" grade answer either- just a simple explanation.

While it states it is for non electricians, videos like this only add to the confusion still present among many in the trade about the differences between grounding and bonding. Ground rods don't trip breakers and save lives, nor will they take the place of a svc neutral should it fail- lots of wiremen still believe that they do. Diy's should be aware that they are not making anything safer when they attempt "ground" a circuit in their house by tying a wire to a rod or some metal pipe that sticks out the dirt and that they risk shock and electrocution by doing so.
 

kwired

Electron manager
Location
NE Nebraska
And what you put there isn't an overly technical "Hawking" grade answer either- just a simple explanation.

While it states it is for non electricians, videos like this only add to the confusion still present among many in the trade about the differences between grounding and bonding. Ground rods don't trip breakers and save lives, nor will they take the place of a svc neutral should it fail- lots of wiremen still believe that they do. Diy's should be aware that they are not making anything safer when they attempt "ground" a circuit in their house by tying a wire to a rod or some metal pipe that sticks out the dirt and that they risk shock and electrocution by doing so.
Nothing wrong with simple, but needs to still be accurate. Like you mentioned there is a lot of confusion just within the trade on differences between grounding and bonding.

We don't need to mislead the untrained, tell them how it is and if they don't get it they don't get it. Do not leave them thinking they know something when they don't by using poor analogies to try to describe something.
 

kwired

Electron manager
Location
NE Nebraska
NEC also is for the general public, for non-electricians. Has it got any leniency?:)
90.1(A):

The purpose of this Code is the practical safeguarding of persons and property from hazards arising from the use of electricity. This Code is not intended as a design specification or an instruction manual for untrained persons.
 

Sahib

Senior Member
Location
India
IMO, NEC is to ensure minimum safety by warning the general public of hazards of using electricity through its definitions,articles, and FPN's.
 

kwired

Electron manager
Location
NE Nebraska
IMO, NEC is to ensure minimum safety by warning the general public of hazards of using electricity through its definitions,articles, and FPN's.
You care to survey the general public and see how many that are not associated with the electrical trades (even if just an office worker where electrical is a big part of their organization) in some way have even heard of the NEC?

Now skip down the page a little to 90.2(A) where it says "This Code covers the installation of...."
 

Sahib

Senior Member
Location
India
Look at 90.1(A) again:

The purpose of this Code is the practical safeguarding of persons and property from hazards arising from the use of electricity.
NEC is for general public safeguarding.

A ground rod is also meant for that purpose.

(Finally I came back on topic.
:))
 

kwired

Electron manager
Location
NE Nebraska
Look at 90.1(A) again:



NEC is for general public safeguarding.

A ground rod is also meant for that purpose.

(Finally I came back on topic.
:))
The general public safeguarding is because the installation that follows NEC requirements is likely going to be safer for the users of the installation then one that doesn't, not that the general public is going to read it and be safer because they gained some knowledge from it.

I can read through health care codes and maybe learn something about health care operations and procedures, doesn't mean I will be a healthier person after I am done reading it though. Doesn't make me a qualified health care provider either.
 

Sahib

Senior Member
Location
India
I agree. NEC does not contain any troubleshooting tips or maintenance procedures even for electricians as it is meant for general public. The ground rod as mentioned in it is for safeguarding of general public.
 

user 100

Senior Member
Location
texas
The NEC is not for the general public. Ground rods don't safeguard the general public.
:thumbsup:

The purpose of the NEC is to provide a set of minimum standards for electrical installations to trained personnel who install electrical systems, nothing more, nothing less.:)
 

Sahib

Senior Member
Location
India
The NEC does not address employee safety. It is an electrical installation standard only. To deal with this problem, NFPA created the Committee on Electrical Safety Requirements for Employee Workplaces—NFPA 70E to develop electrical safety standards that would serve the needs of OSHA. But in 90.1(A) it states its purpose is practical safeguarding of persons from hazards arising from the use of electricity. So it refers to the general public,IMO.
 
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