electricmanscott
Senior Member
- Location
- Boston, MA
Must the #6 cu conductor be unbroken when run from the service to the two ground rods? Or can I run a seperate peice of wire from rod 1 to rod 2?
Suplemental electrode conductor
- Thread starter electricmanscott
- Start date
- Status
- Location
- Bremerton, Washington
Re: Suplemental electrode conductor
The grounding electrode conductor runs unspliced (allowed to splice however with compression or cadweld) to first grounding electrode (what ever it is). Connections from that grounding electrode to any others are bonding jumpers.
See 240.53(C). In other words 2 wires and three clamps is OK, or one wire and 2 clamps if you are attaching to ground rods.
Mike Holts Grounding and Bonding text exlains this topic very well. Do your self a favor and get a copy, call or email his office.
The grounding electrode conductor runs unspliced (allowed to splice however with compression or cadweld) to first grounding electrode (what ever it is). Connections from that grounding electrode to any others are bonding jumpers.
See 240.53(C). In other words 2 wires and three clamps is OK, or one wire and 2 clamps if you are attaching to ground rods.
Mike Holts Grounding and Bonding text exlains this topic very well. Do your self a favor and get a copy, call or email his office.
jtb
Senior Member
- Location
- Pennsylvania
Re: Suplemental electrode conductor
Hmm....I used to run them straight thru unspliced.
...learn sumtin new everyday!
Hmm....I used to run them straight thru unspliced.
...learn sumtin new everyday!
Re: Suplemental electrode conductor
No one agrees with me... but this is a good example of the difference in grounding and bonding.
The ground electrode conductor is connecting the ground/neutral bus, of the service, to the earth.
The bond conductor is shorting the rods, making them one electrode.
The ground electrode conductor should be unspliced to the rod or electrode, the rest of the system is bonding and can be spliced.
This is why I maintain that only one ground electrode conductor should be in the main panel. This conductor should be the largest required according to available electrodes.
A water pipe will require a #4 cu and a rod a #6.
The #4 should start at the service and go the water pipe, and a #6 from the pipe to the rod.
This makes one electrode by being bonded (shorted) together.
No one agrees with me... but this is a good example of the difference in grounding and bonding.
The ground electrode conductor is connecting the ground/neutral bus, of the service, to the earth.
The bond conductor is shorting the rods, making them one electrode.
The ground electrode conductor should be unspliced to the rod or electrode, the rest of the system is bonding and can be spliced.
This is why I maintain that only one ground electrode conductor should be in the main panel. This conductor should be the largest required according to available electrodes.
A water pipe will require a #4 cu and a rod a #6.
The #4 should start at the service and go the water pipe, and a #6 from the pipe to the rod.
This makes one electrode by being bonded (shorted) together.
Re: Suplemental electrode conductor
I need to correct part of my first response...The ground rods should be near the panel, this will require a #4 to the rods then to the water pipe.
The rods, or a Ufer ground, should be near the panel to avoid any transient impulse from entering the premises wiring.
I need to correct part of my first response...The ground rods should be near the panel, this will require a #4 to the rods then to the water pipe.
The rods, or a Ufer ground, should be near the panel to avoid any transient impulse from entering the premises wiring.
- Location
- Bremerton, Washington
Re: Suplemental electrode conductor
Bennie I agree with you. One GEC to the panel. Bond all electrodes others to that electrode.
Bennie I agree with you. One GEC to the panel. Bond all electrodes others to that electrode.
Re: Suplemental electrode conductor
Tom: Thanks for the response...You add credibility to this procedure.
When I was inspecting, I always questioned more than one ground conductor on the bus. I always got the same response,"they are bonded at the bus". I say they are fed from the bus.
Tom: Thanks for the response...You add credibility to this procedure.
When I was inspecting, I always questioned more than one ground conductor on the bus. I always got the same response,"they are bonded at the bus". I say they are fed from the bus.
- Location
- Illinois
- Occupation
- retired electrician
Re: Suplemental electrode conductor
While I understand the technical merits of a single grounding electrode connection to the grounded conductor, this is not a code requirement. 250.64(F) permits an individual GEC to be installed from the grounded conductor to each grounding electrode.
Don
While I understand the technical merits of a single grounding electrode connection to the grounded conductor, this is not a code requirement. 250.64(F) permits an individual GEC to be installed from the grounded conductor to each grounding electrode.
Don
jxofaltrds
Inspector Mike®
- Location
- Mike P. Columbus Ohio
- Occupation
- ESI, PI, RBO
Re: Suplemental electrode conductor
Bennie
No one agrees with me either(here in Ohio). Isn't it called a ground bar? Not a bonding bar? Would they be parrelled conductors to earth if attached at the panel? Would there be the possiblity that the two could have different potentials?
I bond as Bennie and Tom have explained.
Mike P.
Bennie
No one agrees with me either(here in Ohio). Isn't it called a ground bar? Not a bonding bar? Would they be parrelled conductors to earth if attached at the panel? Would there be the possiblity that the two could have different potentials?
I bond as Bennie and Tom have explained.
Mike P.
Re: Suplemental electrode conductor
You are exactly right Mike. Two separate ground rods, with separate conductors is like connecting to a battery.
The earth will have a difference in potential, creating a ground loop, from an external source.
Imagine the two conductors as being active line conductors. Each one will have a different impedance and resultant current flow.
Making multiple connections to a ground grid, is single point grounding. Multiple connections to an inductor(earth)is multi-point grounding.
You are exactly right Mike. Two separate ground rods, with separate conductors is like connecting to a battery.
The earth will have a difference in potential, creating a ground loop, from an external source.
Imagine the two conductors as being active line conductors. Each one will have a different impedance and resultant current flow.
Making multiple connections to a ground grid, is single point grounding. Multiple connections to an inductor(earth)is multi-point grounding.
Re: Suplemental electrode conductor
Just my 2 cents worth, I thought the water pipe was the grounding electrode, if nothing else is available, you go to it and the ground rod is a suppliement to the water pipe, in the event the we lose the water pipe.
As far as a difference in potential of the earth theoretically it suppose to be zero. or depending on how well the utility has there supply balanced.
In my area you must run the no.6 back to the panel and from another lug in that same panel to the water meter, which give three paths back to the transformer.
One good one(neutral) one not-so good (the water line) and the ugly one the ground rod(s)
Does anyone know when the utility started grounding their primary to the secondary and what the reasoning was ????????
Wm.Colt
[ June 05, 2003, 06:25 PM: Message edited by: wocolt ]
Just my 2 cents worth, I thought the water pipe was the grounding electrode, if nothing else is available, you go to it and the ground rod is a suppliement to the water pipe, in the event the we lose the water pipe.
As far as a difference in potential of the earth theoretically it suppose to be zero. or depending on how well the utility has there supply balanced.
In my area you must run the no.6 back to the panel and from another lug in that same panel to the water meter, which give three paths back to the transformer.
One good one(neutral) one not-so good (the water line) and the ugly one the ground rod(s)
Does anyone know when the utility started grounding their primary to the secondary and what the reasoning was ????????
Wm.Colt
[ June 05, 2003, 06:25 PM: Message edited by: wocolt ]
electricmanscott
Senior Member
- Location
- Boston, MA
Re: Suplemental electrode conductor
Standard procedure around here is # 4 cu to water pipe from panel with main (or disconnect), leftover #4 CU from lug in meter socket to ground rod. Most inspectors don't seem to require (follow the NEC) two rods. I put two in but they never even check. :roll:
Standard procedure around here is # 4 cu to water pipe from panel with main (or disconnect), leftover #4 CU from lug in meter socket to ground rod. Most inspectors don't seem to require (follow the NEC) two rods. I put two in but they never even check. :roll:
rasmithircgov.com
Member
- Location
- Florida
Re: Suplemental electrode conductor
Bonding is also part of the procedure to connect electrodes in the grounding electrode system .Via 250-50 "If avalible on the premises at each building or structure served, each item (a)thru (d),and any made electrodes in accordance with 250-52 (c) and (d)shall be BONDED together to form a grounding electrode system".
Bonding is also part of the procedure to connect electrodes in the grounding electrode system .Via 250-50 "If avalible on the premises at each building or structure served, each item (a)thru (d),and any made electrodes in accordance with 250-52 (c) and (d)shall be BONDED together to form a grounding electrode system".
rasmithircgov.com
Member
- Location
- Florida
Re: Suplemental electrode conductor
Also with what size service entrance conductors are being ran to what size service that you can use a #4 t the Metal water piping if your using table 250-66 to size the conductor. If you go to the rod 1st it has to be sized for the largest electrode conductor in the system.Concrete encased electrode only requires a #4 while supplementing the metal water piping.#6 for rod and pipes,plate electrodes supplimental.Lots of variables to be looked at.
Also with what size service entrance conductors are being ran to what size service that you can use a #4 t the Metal water piping if your using table 250-66 to size the conductor. If you go to the rod 1st it has to be sized for the largest electrode conductor in the system.Concrete encased electrode only requires a #4 while supplementing the metal water piping.#6 for rod and pipes,plate electrodes supplimental.Lots of variables to be looked at.
Re: Suplemental electrode conductor
rasmith: I agree. The size of the ground electrode conductor, at the panel, should be the largest size required, according to the available electrodes.
This was the original reason for the 5 foot rule on the water pipe. This 5 foot was to serve as a bonding bus for the ground electrode system.
The reason,on record,for the 5 foot limitation is stated as being a precaution for maintaining continuity in the piping system.
Using the real reason, for justification, would be
ruled a design issue and be rejected. The so called safety issue of the possibility of replacing the interior pipe with plastic, is a bit far fetched.
When has there been a code rule based on speculation? This is called "card reading" or "crystal ball gazing", in the real world.
[ June 06, 2003, 11:48 AM: Message edited by: bennie ]
rasmith: I agree. The size of the ground electrode conductor, at the panel, should be the largest size required, according to the available electrodes.
This was the original reason for the 5 foot rule on the water pipe. This 5 foot was to serve as a bonding bus for the ground electrode system.
The reason,on record,for the 5 foot limitation is stated as being a precaution for maintaining continuity in the piping system.
Using the real reason, for justification, would be
ruled a design issue and be rejected. The so called safety issue of the possibility of replacing the interior pipe with plastic, is a bit far fetched.
When has there been a code rule based on speculation? This is called "card reading" or "crystal ball gazing", in the real world.
[ June 06, 2003, 11:48 AM: Message edited by: bennie ]
Re: Suplemental electrode conductor
250.66(B)...When the ground electrode is a rod, pipe, or plate, that portion of the conductor that is the sole connection to the grounding electrode shall not be required to be larger than #6 cu or #4 al.
The words "That portion", are the key words to substantiate my opinion of bonding all electrodes, not feeding all electrodes individually.
250.66(B)...When the ground electrode is a rod, pipe, or plate, that portion of the conductor that is the sole connection to the grounding electrode shall not be required to be larger than #6 cu or #4 al.
The words "That portion", are the key words to substantiate my opinion of bonding all electrodes, not feeding all electrodes individually.
pierre
Senior Member
- Location
- Westchester County, New York
Re: Suplemental electrode conductor
Grounding and Bonding
I would like to say, if a person was to install the GEC from the Ground Rod and the cold water pipe separately to the service panel, it is permited in the NEC, because once they are both installed to the same bus, they are electrically connected and of the same potential. If the cold water pipe GEC was to become disconnected for whatever reason, then the Ground Rod would become the primary (could be of poor quality) Ground Electrode. Some inspectors think this is better than bonding the Rod to the cold water and then only one GEC is connected to the service.
I ask, how important is the GEC to facilitate the overcurrent protective device (fuse, ciruit breaker)? It is of no importance. The Neutral at the 1st point of disconnect (usually the service) is extremely important for that purpose.
The Transformer for the utility is already grounded by the utility, so voltage stabilization is protected, so what does the GEC system at say, a dwelling perform?
Comments would be welcomed!
Grounding and Bonding
I would like to say, if a person was to install the GEC from the Ground Rod and the cold water pipe separately to the service panel, it is permited in the NEC, because once they are both installed to the same bus, they are electrically connected and of the same potential. If the cold water pipe GEC was to become disconnected for whatever reason, then the Ground Rod would become the primary (could be of poor quality) Ground Electrode. Some inspectors think this is better than bonding the Rod to the cold water and then only one GEC is connected to the service.
I ask, how important is the GEC to facilitate the overcurrent protective device (fuse, ciruit breaker)? It is of no importance. The Neutral at the 1st point of disconnect (usually the service) is extremely important for that purpose.
The Transformer for the utility is already grounded by the utility, so voltage stabilization is protected, so what does the GEC system at say, a dwelling perform?
Comments would be welcomed!
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