two grounds on one rod?
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Re: two grounds on one rod?
All the meter enclosures I am aware of have the Grounded Conductor (Neutral) terminal rivoted to the enclosure, thus if bonding the Grounded Conductor to the Case or to the Grounding Electrode within the Main Disconnect enclosure and a metal raceway is used between the Meter enclosure and the Main Disconnect Enclosure - there will always be a parallel path for the grounded conductor.
Using a GEC from the Meter to a ground rod ( or any other Ground Electrode ) and another GEC from the Main disconnect enclosure to the same Ground Electrode (GE), ( remember all GE's are to be bonded together) those GEC's will provide a parallel path with the grounded conductor.
In general, it is difficult for Service Equipment not to have a parallel path for the grounded conductor if more than one GE or more than one GEC is used.
Glenn
All the meter enclosures I am aware of have the Grounded Conductor (Neutral) terminal rivoted to the enclosure, thus if bonding the Grounded Conductor to the Case or to the Grounding Electrode within the Main Disconnect enclosure and a metal raceway is used between the Meter enclosure and the Main Disconnect Enclosure - there will always be a parallel path for the grounded conductor.
Using a GEC from the Meter to a ground rod ( or any other Ground Electrode ) and another GEC from the Main disconnect enclosure to the same Ground Electrode (GE), ( remember all GE's are to be bonded together) those GEC's will provide a parallel path with the grounded conductor.
In general, it is difficult for Service Equipment not to have a parallel path for the grounded conductor if more than one GE or more than one GEC is used.
Glenn
Re: two grounds on one rod?
All the meter enclosures I am aware of have the Grounded Conductor (Neutral) terminal rivoted to the enclosure, thus if bonding the Grounded Conductor to the Case or to the Grounding Electrode within the Main Disconnect enclosure and a metal raceway is used between the Meter enclosure and the Main Disconnect Enclosure - there will always be a parallel path for the grounded conductor.
Using a GEC from the Meter to a ground rod ( or any other Ground Electrode ) and another GEC from the Main disconnect enclosure to the same Ground Electrode (GE), ( remember all GE's are to be bonded together) those GEC's will provide a parallel path with the grounded conductor.
In general, it is difficult for Service Equipment not to have a parallel path for the grounded conductor if more than one GE or more than one GEC is used.
Glenn
All the meter enclosures I am aware of have the Grounded Conductor (Neutral) terminal rivoted to the enclosure, thus if bonding the Grounded Conductor to the Case or to the Grounding Electrode within the Main Disconnect enclosure and a metal raceway is used between the Meter enclosure and the Main Disconnect Enclosure - there will always be a parallel path for the grounded conductor.
Using a GEC from the Meter to a ground rod ( or any other Ground Electrode ) and another GEC from the Main disconnect enclosure to the same Ground Electrode (GE), ( remember all GE's are to be bonded together) those GEC's will provide a parallel path with the grounded conductor.
In general, it is difficult for Service Equipment not to have a parallel path for the grounded conductor if more than one GE or more than one GEC is used.
Glenn
Re: two grounds on one rod?
Glenn,
As far as 250.6
"250.6 Objectionable Current over Grounding Conductors.
(A) Arrangement to Prevent Objectionable Current. The grounding of electrical systems, circuit conductors, surge arresters, and conductive non–current-carrying materials and equipment shall be installed and arranged in a manner that will prevent objectionable current over the grounding conductors or grounding paths.
Is this talking present as in when installed, or during a fault condition?
If we're speaking present, what exactly is objectionable?
If we're talking about fault conditions that would be temporary, (no mention of how much damage must be done before it is not temporary per the NEC) grounding as many times as could be monetarily afforded upstrem of the "Main" would be legal under 250.6 (C)
Roger
[ August 18, 2003, 08:25 PM: Message edited by: roger ]
Glenn,
exactly.
As far as 250.6
"250.6 Objectionable Current over Grounding Conductors.
(A) Arrangement to Prevent Objectionable Current. The grounding of electrical systems, circuit conductors, surge arresters, and conductive non–current-carrying materials and equipment shall be installed and arranged in a manner that will prevent objectionable current over the grounding conductors or grounding paths.
Is this talking present as in when installed, or during a fault condition?
If we're speaking present, what exactly is objectionable?
If we're talking about fault conditions that would be temporary, (no mention of how much damage must be done before it is not temporary per the NEC) grounding as many times as could be monetarily afforded upstrem of the "Main" would be legal under 250.6 (C)
Roger
[ August 18, 2003, 08:25 PM: Message edited by: roger ]
pierre
Senior Member
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- Westchester County, New York
Re: two grounds on one rod?
Roger
250.6(C) mentions ground faults as not being considered objectional current.
I will try to keep it short, here is my take on this. I welcome any comments positive or not.
Objectional current as far as the NEC is concerned is neutral current traveling on the equipment grounding conductor. this is obviously a dangerous situation.
Remembering that all electrons that leave a source are trying to get back to the source, they will travel any and all paths available to them.
I know that some guys abhore the thought of using PVC, but in a dwelling unit it is one way of deterring objectional current at the service.
Pierre
[ August 18, 2003, 10:53 PM: Message edited by: pierre ]
Roger
250.6(C) mentions ground faults as not being considered objectional current.
I will try to keep it short, here is my take on this. I welcome any comments positive or not.
Objectional current as far as the NEC is concerned is neutral current traveling on the equipment grounding conductor. this is obviously a dangerous situation.
Remembering that all electrons that leave a source are trying to get back to the source, they will travel any and all paths available to them.
I know that some guys abhore the thought of using PVC, but in a dwelling unit it is one way of deterring objectional current at the service.
Pierre
[ August 18, 2003, 10:53 PM: Message edited by: pierre ]
Re: two grounds on one rod?
Roger,
Just an example of metal conduit between meter and panelboard, see http://electrical-contractor.net/ubb/Forum2/HTML/000823.html
Roger,
Just an example of metal conduit between meter and panelboard, see http://electrical-contractor.net/ubb/Forum2/HTML/000823.html
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