grd/neutral

[enireh]

why do we not separate the grd from the neutral at the main panel and at what point is it most important to separate them. for example if a main panel is two feet away from the meter that is ok to have neutral and grounds together but at what distance do they need to be separated or is it not a distance issue? I'll take my answer off the air thank you

 

[Dennis Alwon]

why do we not separate the grd from the neutral at the main panel and at what point is it most important to separate them. For example, if a main panel is two feet away from the meter that is ok to have neutral and grounds together but at what distance do they need to be separated or is it not a distance issue? I'll take my answer off the air thank you

Distance has nothing to do with when the neutral and the equipment grounding conductor must be separated, The neutral and equipment grounding conductor's are bonded together in the service panel or service disconnect and once any feeder or branch circuit leaves these panels then the neutral and equipment grounding conductor must be separated.

 

[GoldDigger]

The one exception is that if there is a bond at the meter there may also be a bond at the main panel IF there is no metallic connection (wire or raceway EGC) between the two points.

The governing principle is that after the service point the EGC must not act as a parallel metallic path for neutral current.

 

[ActionDave]

why do we not separate the grd from the neutral at the main panel and at what point is it most important to separate them. for example if a main panel is two feet away from the meter that is ok to have neutral and grounds together but at what distance do they need to be separated or is it not a distance issue? I'll take my answer off the air thank you

The best answer I have ever heard is one that was given to me on this forum a long time ago. Electrons know what side of the service disconnect they are on and behave accordingly.

I have a question for you. Why do you keep asking this question? What is it that you are trying to uncover?

 

[Jberg73]

Seems like I've seen this question before. Action Dave, your question seems more relevant.

Sent from my BLU LIFE ONE X using Tapatalk

 

[Ingenieur]

Not clear on the question

the N and G serve 2 distinct functions
the N is normally a current conductor and is connected to the load
the G only carries fault/abnormal currents and is not connected to the load
but the current they carry returns to the same source point
the G only carries i if something goes wrong, insulation failure, broken H wire to G, equipment failure, etc

if you bonded them within the premises and had a load on the far side of the bond the normal current would divide and use both the N and G to rtn to the source
the result is the frame (boxes, conduit, enclosures) between bond would possibly be raised above ground potential or 0 volt
not good
keeping this as close to the entrance as possible reduces the likelyhood of contact by occupants

 

[enireh]

grd/neutral

Not clear on the question

the N and G serve 2 distinct functions
the N is normally a current conductor and is connected to the load
the G only carries fault/abnormal currents and is not connected to the load
but the current they carry returns to the same source point
the G only carries i if something goes wrong, insulation failure, broken H wire to G, equipment failure, etc

if you bonded them within the premises and had a load on the far side of the bond the normal current would divide and use both the N and G to rtn to the source
the result is the frame (boxes, conduit, enclosures) between bond would possibly be raised above ground potential or 0 volt
not good
keeping this as close to the entrance as possible reduces the likelyhood of contact by occupants

thank you

 

[Smart $]

...The governing principle is that after the service point the EGC must not act as a parallel metallic path for neutral current.

After the service disconnecting means.

Most AHJ's will not flag inadvertent parallel ground conductor pathways on the line side of the service disconnecting means. An example is metal raceway between a meter and the disconnect where the grounded conductor is bonded to each enclosure.

 

[kwired]

The one exception is that if there is a bond at the meter there may also be a bond at the main panel IF there is no metallic connection (wire or raceway EGC) between the two points.

The governing principle is that after the service point the EGC must not act as a parallel metallic path for neutral current.

Smart$ beat me to replying on this.

The EGC doesn't start until the service disconnect enclosure.

Every metal enclosure on the supply side and including the service disconnect is bonded to the grounded conductor, any electrically continuous raceways between them will be carrying some neutral current.

 

[GoldDigger]

After the service disconnecting means.

Most AHJ's will not flag inadvertent parallel ground conductor pathways on the line side of the service disconnecting means. An example is metal raceway between a meter and the disconnect where the grounded conductor is bonded to each enclosure.

I guess I was thinking of the provision for separately derived systems, not services.
[2011]

Exception No. 2: A system bonding jumper at both the
source and the first disconnecting means shall be permitted
if doing so does not establish a parallel path for the
grounded conductor If a grounded conductor is used in this
manner, it shall not be smaller than the size specified for
the system bonding jumper but shall not be required to be
larger than the ungrounded conductor(s). For the purposes
of this exception, connection through the earth shall not be
considered as providing a parallel path.