Mixing neutral and grounding connection
- Thread starter tagmar
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- Status
- Location
- Massachusetts
Re: Mixing neutral and grounding connection
It depends.
Does this panel have the service disconnect (main) in it or is the service disconnect at the meter or another panel?
When he said mixed did he mean on the same bar or a white and bare wire under the same screw?
Unless you can be more specific it is really not something that can be answered here.
It depends.
Does this panel have the service disconnect (main) in it or is the service disconnect at the meter or another panel?
When he said mixed did he mean on the same bar or a white and bare wire under the same screw?
Unless you can be more specific it is really not something that can be answered here.
Re: Mixing neutral and grounding connection
This Service panel is inside and has main shutoff breaker, The main service panel is outsite by the P&G meter and also has breaker to shutoff power to inside service panel.
I saw some white wires(2 wires) and some bare wires (2wires) are connected to same bar. I hope this help to get an answer. Thank you.
This Service panel is inside and has main shutoff breaker, The main service panel is outsite by the P&G meter and also has breaker to shutoff power to inside service panel.
I saw some white wires(2 wires) and some bare wires (2wires) are connected to same bar. I hope this help to get an answer. Thank you.
- Location
- Bremerton, Washington
- Occupation
- Master Electrician
Re: Mixing neutral and grounding connection
Our experience here at the forum with home inspectors has been that many are not qualified to inspect electrical.
However based on your description of your electrical service, he/she may be correct.
And point out to your Home Inspector that the NEC does not recoginze the terms "Ground" and "Neutral". Ask for a specific code reference for his comment, or at least an explaination of what the hazard is for the condition he cited.
What makes you question the home inspectors comment?
Our experience here at the forum with home inspectors has been that many are not qualified to inspect electrical.
However based on your description of your electrical service, he/she may be correct.
And point out to your Home Inspector that the NEC does not recoginze the terms "Ground" and "Neutral". Ask for a specific code reference for his comment, or at least an explaination of what the hazard is for the condition he cited.
What makes you question the home inspectors comment?
Re: Mixing neutral and grounding connection
How old is this installation? This brings up the old three wire versus the four wire feeder debate.
I got trashed on this subject before when I wrote that no where in the code book does it state the equipment ground wires and neutral wires must be separated in a panel.
There is no such thing as a sub panel. All panels are service panels and should be treated as such, in allowing the neutral to ground the panel.
With the main switch outside, four conductors are required from the load side of the switch to the panel. Remove the switch and three wires are permitted. This is baloney technology. With the increase in copper prices this makes no sense to run a fourth wire for nothing.
[ February 29, 2004, 02:19 PM: Message edited by: bennie ]
How old is this installation? This brings up the old three wire versus the four wire feeder debate.
I got trashed on this subject before when I wrote that no where in the code book does it state the equipment ground wires and neutral wires must be separated in a panel.
There is no such thing as a sub panel. All panels are service panels and should be treated as such, in allowing the neutral to ground the panel.
With the main switch outside, four conductors are required from the load side of the switch to the panel. Remove the switch and three wires are permitted. This is baloney technology. With the increase in copper prices this makes no sense to run a fourth wire for nothing.
[ February 29, 2004, 02:19 PM: Message edited by: bennie ]
Re: Mixing neutral and grounding connection
He made afew more remarks that were incorrect. The sevice panel was inspected with City of San Jose and did not say anything about the problems he mentioned. I am asking just for the sake of safety and I like to know if I need to ask an electrician look at the service panel.
Thank you for help.
He made afew more remarks that were incorrect. The sevice panel was inspected with City of San Jose and did not say anything about the problems he mentioned. I am asking just for the sake of safety and I like to know if I need to ask an electrician look at the service panel.
Thank you for help.
Re: Mixing neutral and grounding connection
I could have guessed this is in California. Check for the date of original installation. California did not consider a four wire feed to a panel when it was fed by a cable assembly.
The installation is probably legal based on date.
It will operate fine and not be a safety hazard. The fault path will be a lower impedance than a four wire feed.
I could have guessed this is in California. Check for the date of original installation. California did not consider a four wire feed to a panel when it was fed by a cable assembly.
The installation is probably legal based on date.
It will operate fine and not be a safety hazard. The fault path will be a lower impedance than a four wire feed.
russ
Senior Member
- Location
- Burbank IL
Re: Mixing neutral and grounding connection
bennie:
When the "subpanel" is fed using a metal conduit system, how could you ever allow the neutrals and the grounds to be tied together?
tagmar:
Have an electrician look at your panels, so he can determine where the grounding and bonding has been done.
bennie:
When the "subpanel" is fed using a metal conduit system, how could you ever allow the neutrals and the grounds to be tied together?
tagmar:
Have an electrician look at your panels, so he can determine where the grounding and bonding has been done.
pierre
Senior Member
- Location
- Westchester County, New York
Re: Mixing neutral and grounding connection
Here we go again....
If the panel downstream of the first panel in a premise has the equipment ground conductor and the grounded conductor connected together on the same bus, will 'neutral' current not flow on both the grounded and equipment ground conductor back to the source?
If so, do you think this is acceptable? safe? or doesn't matter?
Pierre
Here we go again....
If the panel downstream of the first panel in a premise has the equipment ground conductor and the grounded conductor connected together on the same bus, will 'neutral' current not flow on both the grounded and equipment ground conductor back to the source?
If so, do you think this is acceptable? safe? or doesn't matter?
Pierre
- Location
- Massachusetts
Re: Mixing neutral and grounding connection
What is wrong with doing it the way shown in this graphic?
We all understand it, and other metallic paths between panels do not become neutral conductors.
What is wrong with doing it the way shown in this graphic?
We all understand it, and other metallic paths between panels do not become neutral conductors.
- Location
- Bremerton, Washington
- Occupation
- Master Electrician
Re: Mixing neutral and grounding connection
Pierre:
Does matter
Not safe
Mike Holt has video from the City of Miami on Open Neutrals (about $20 from his office) that shows fires from neutral current that can not get back to the source. Could the same thing happen here? Maybe.
The neutral current is flowing on any metallic parts between the main service and feeder.
Pierre:
Does matter
Not safe
Mike Holt has video from the City of Miami on Open Neutrals (about $20 from his office) that shows fires from neutral current that can not get back to the source. Could the same thing happen here? Maybe.
The neutral current is flowing on any metallic parts between the main service and feeder.
Re: Mixing neutral and grounding connection
I am referring to a dwelling unit with NM cable.
Alterations to prevent multiple grounding connections should be performed according to 250.6.B.
When 3/wire SE cable is used to feed the panels. There are no multiple grounding connections.
A neutral, under load, does not have much potential difference to ground. A conduit with current flow has no significient voltage to ground. A remote panel will not have any touch voltage problem when the neutral is connected to the enclosure.
As far as fire danger, all loose connections are a potential cause.
I am referring to a dwelling unit with NM cable.
Alterations to prevent multiple grounding connections should be performed according to 250.6.B.
When 3/wire SE cable is used to feed the panels. There are no multiple grounding connections.
A neutral, under load, does not have much potential difference to ground. A conduit with current flow has no significient voltage to ground. A remote panel will not have any touch voltage problem when the neutral is connected to the enclosure.
As far as fire danger, all loose connections are a potential cause.
jxofaltrds
Inspector Mike®
- Location
- Mike P. Columbus Ohio
- Occupation
- ESI, PI, RBO
Re: Mixing neutral and grounding connection
I think he is saying that the grounded conductor and the equipment ground are under the same lug.
Mike P.
I think he is saying that the grounded conductor and the equipment ground are under the same lug.
Mike P.
caosesvida
Senior Member
Re: Mixing neutral and grounding connection
I am a little confused here. Are you saying that in california you have to run a four wire feeder to a service panel from the meter pan?? Are you then using the main service disconnect in the main panel in the house or are you using a disconnect outside at the meter and main lugging inside?? I am new to this site and seems I have missed this discussion. thanks for an answer.
I am a little confused here. Are you saying that in california you have to run a four wire feeder to a service panel from the meter pan?? Are you then using the main service disconnect in the main panel in the house or are you using a disconnect outside at the meter and main lugging inside?? I am new to this site and seems I have missed this discussion. thanks for an answer.
pierre
Senior Member
- Location
- Westchester County, New York
Re: Mixing neutral and grounding connection
Bennie
It would be beneficial to others for you to state when your views stray from what is required by the NEC, whether you like the requirement or not.
Pierre
Bennie
It would be beneficial to others for you to state when your views stray from what is required by the NEC, whether you like the requirement or not.
Pierre
- Location
- Massachusetts
Re: Mixing neutral and grounding connection
Bennie you have seen these before, but you asked for documentation so here it is.
Bennie you have seen these before, but you asked for documentation so here it is.
What part of either one of these would allow me to use the neutral to ground the enclosure of a panel that does not include the service disconnecting means?
Re: Mixing neutral and grounding connection
I interpret the word grounding as defined in the NEC.
Paraphrased;
Grounding Conductor; A conductor used to connect equipment or the grounded circuit conductor(neutral) to a grounding electrode.
This is telling me the neutral can not be connected to earth except in the service equipment.
Using the neutral to ground panels is permitted in service equipment. There is no such thing in the NEC as a sub-panel, therefore the panels are an extension of the service, and the neutral can be used for grounding and for a fault path of lowest impedance.
The neutral conductor should not be used for grounding equipment or material when there is a chance of polarity reversal.
Everyone can interpret the concept according to the description in the handbook. There is nothing wrong with that method except a waste of copper.
My understanding is correct in my opinion. Anyone is welcome to prove me wrong.
I interpret the word grounding as defined in the NEC.
Paraphrased;
Grounding Conductor; A conductor used to connect equipment or the grounded circuit conductor(neutral) to a grounding electrode.
This is telling me the neutral can not be connected to earth except in the service equipment.
Using the neutral to ground panels is permitted in service equipment. There is no such thing in the NEC as a sub-panel, therefore the panels are an extension of the service, and the neutral can be used for grounding and for a fault path of lowest impedance.
The neutral conductor should not be used for grounding equipment or material when there is a chance of polarity reversal.
Everyone can interpret the concept according to the description in the handbook. There is nothing wrong with that method except a waste of copper.
My understanding is correct in my opinion. Anyone is welcome to prove me wrong.
Re: Mixing neutral and grounding connection
All of my responses to this topic are in consideration of the wiring method being NM cable.
Metal conduit, to a panel, will make two grounding connections. One path will have to be defeated.
There has never been wording in the NEC requiring separation of ground and neutrals in a panel. This is only one method to defeat multiple ground to neutral connections that create common mode current flow.
For years, panels did not have but one factory installed bus. Except in metal conduit wiring methods, one terminal strip should be all that is necessary. This makes the neutral conductor a fault path instead of a smaller conductor.
Engineers reading this thread, please jump in.
[ March 02, 2004, 07:02 PM: Message edited by: bennie ]
All of my responses to this topic are in consideration of the wiring method being NM cable.
Metal conduit, to a panel, will make two grounding connections. One path will have to be defeated.
There has never been wording in the NEC requiring separation of ground and neutrals in a panel. This is only one method to defeat multiple ground to neutral connections that create common mode current flow.
For years, panels did not have but one factory installed bus. Except in metal conduit wiring methods, one terminal strip should be all that is necessary. This makes the neutral conductor a fault path instead of a smaller conductor.
Engineers reading this thread, please jump in.
[ March 02, 2004, 07:02 PM: Message edited by: bennie ]
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