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  1. #1
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    Default Ground connection in panel

    The service panel is located in basement within three feet of the electric meter. The neutral and ground terminals within the panel are bonded. The panel does not have a visible grounding conductor. The meter is grounded via ground rod at exterior.

    I understand that the service equipment can be grounded at the meter, but shouldn't there also be a visible ground conductor inside the panel connected to neutral and ground terminal bars?

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  2. #2
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    Default Re: Ground connection in panel

    Quote Originally Posted by Ken Amelin View Post
    The service panel is located in basement within three feet of the electric meter. The neutral and ground terminals within the panel are bonded. The panel does not have a visible grounding conductor. The meter is grounded via ground rod at exterior.

    I understand that the service equipment can be grounded at the meter, but shouldn't there also be a visible ground conductor inside the panel connected to neutral and ground terminal bars?
    Ken,

    I believe you are correct that bonding of the neutral and EGC can occur at the meter instead of the service equipment. However, I have never seen it in my area. As a result, I am going to try an educated guess (semi-educated?)

    If bonded at the meter, then it seems to me that a four-wire feed would be needed between the meter and the service equipment. What I see in your pic looks more like an EGC than a neutral conductor because the neutral would be insulated.

    Is the raceway between the meter and panel metal or PVC?

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  3. #3
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    Default Re: Ground connection in panel

    I was really hoping someone other than me would respond, either to confirm or contradict me.

    Jerry?
    Speedy?
    Jim?
    Rollie?
    Anyone?
    Bueller?

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  4. #4
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    Default Re: Ground connection in panel

    Grounding is not allowed in meter sockets here, but I believe that sounds correct. No need for the 4th conductor since you are ahead of the first means of disconnect.

    All answers based on unamended National Electrical codes.

  5. #5
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    Default Re: Ground connection in panel

    250.24 Grounding Service-Supplied Alternating-Current Systems.
    (A) System Grounding Connections. ( says to connect the grounded service conductor in accordance with 250.24(A)(1) through (5) )
    (1) General. The grounding electrode conductor connection shall be made at any accessible point from the load end of the overhead service conductors, service drop, underground service conductors, or service lateral to. including the terminal or bus to which the grounded service conductor is connected at the service disconnecting mean.

    Which basically means that the grounding connection to the grounded conductor can be made in the meter can (where the local utility allows it, and some local utilities demand it be made in the meter can, while other local utilities say 'no way, not in the meter can where our meter is, we don't want anyone messing with out meters') or in the service equipment.

    As long as the location is "any accessible point" ... which takes us to here:

    Accessible (as applied to equipment). Admitting close approach, not guarded by locked doors, elevation, or other effective means.

    Accessible (as applied to wiring methods). (the connection of the grounded conductor is not a "wiring method", but it is in "equipment", thus the definition "as applied to equipment" applies)

    Seems to me that the meter, being in the meter can, with a seal locking the meter cover in place, is "or other effective means." of being "guarded" - which means that, if not required by the local utility, that the connection should not be in the meter can.

    Not all agree with that assessment, though.

    And, if the local utility states that the connection shall be in the meter can, then any fee, charge, or other twist they want to apply to someone who breaks their seal means that they required a code violation of that connection being within their guarded meter can ... so go suck an egg and leave us alone ... or stop insisting that is an accessible location and then saying that it is not.

    Oh, as Jim said, the fourth conductor is not necessary.

    Jerry Peck
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  6. #6
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    Default Re: Ground connection in panel

    Ken,

    Okay, there you have it. Gunnar was wrong!

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  7. #7
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    Default Re: Ground connection in panel

    Jim & Jerry,

    I have never seen that, but I am interested in making this clear in my own head. The condition at the installation that Ken described is:


    1. Neutral is (presumably) bonded to the grounding electrode at/near the transformer (not something that we would normally see).
    2. Two ungrounded (voltage-carrying) conductors and one grounded conductor are run from the transformer to the meter at the exterior of the building.
    3. Neutral is bonded at the meter enclosure/can, and the grounding electrode conductor is connected within the meter can to the grounding electrode(s).
    4. Two ungrounded conductors and one grounded (bare) conductor are run (presumably through some kind of raceway) to the service equipment a few feet away at the interior of the building.
    5. Neutral and equipment grounding conductors are again bonded. No GEC at this location.


    Is this correct?

    Would it be acceptable to bond at the meter but have the GEC connected at the service equipment?

    Why isn't the grounded conductor between the meter and service equipment insulated?

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  8. #8
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    Default Re: Ground connection in panel

    Quote Originally Posted by Gunnar Alquist View Post
    I have never seen that, but I am interested in making this clear in my own head. The condition at the installation that Ken described is:


    1. Neutral is (presumably) bonded to the grounding electrode at/near the transformer (not something that we would normally see).
    2. Two ungrounded (voltage-carrying) conductors and one grounded conductor are run from the transformer to the meter at the exterior of the building.
    3. Neutral is bonded at the meter enclosure/can, and the grounding electrode conductor is connected within the meter can to the grounding electrode(s).
    4. Two ungrounded conductors and one grounded (bare) conductor are run (presumably through some kind of raceway) to the service equipment a few feet away at the interior of the building.
    5. Neutral and equipment grounding conductors are again bonded. No GEC at this location.


    Is this correct?
    Item 5 above is unnecessary and inherent in the fact that the neutral and ground are one and the same - however - the enclosure at the service equipment needs to somehow be bonded to ground (which is also the neutral).

    That bonding could be a bonding screw from neutral/ground into the enclosure, a grounding/bonding bushing on metal conduit which runs between the meter and service equipment enclosure (if metal conduit is present), or it could even be that 4th wire which was referenced (that 4th wire would simply be a long bonding jumper from the meter ground/neutral connection to the grounding connection at the service equipment).

    Would it be acceptable to bond at the meter but have the GEC connected at the service equipment?
    Only if there was the above described grounding path between the service equipment enclosure and the meter.

    Keep in mind that there are two basic types of wiring in meter cans: a) the neutral terminal is permanently attached to the meter can enclosure during manufacture; b) the neutral terminal is isolated from the meter can, which then needs to be bonded to the meter can to ground the meter can. Most of the meter cans I've seen on residential are the types with the neutral permanently attached to the meter can enclosure. I've seen the other types on commercial, industrial, and cell phone tower services - and the most common error there is that they forget to somehow ground the metal meter can (but that is going back 6 years to before I retired from doing code inspections, I don't know if they are still making that error or not).

    Why isn't the grounded conductor between the meter and service equipment insulated?
    Because the code allows that neutral* to not be insulated, and its length into the structure ('into' means 'beyond the exterior surface of the exterior wall' of the structure), and basically limits the length of the service entrance conductors to 5 feet 'from the point of entrance' into the structure to the service disconnect (keep in mind that the service entrance conductors also do not have any protective overcurrent device on the line side, the main service disconnect only protects the load end and in).

    Added * with edit:
    * "neutral" in: "code allows that neutral to not be insulated" refers to service entrance conductors only, all other neutrals are required to be insulated

    Last edited by Jerry Peck; 05-02-2020 at 08:00 AM. Reason: Added "*" for clarification of which neutral conductor
    Jerry Peck
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  9. #9
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    Default Re: Ground connection in panel

    Thanks Jerry,

    There is a lot there. I am going to have to ponder this a bit.

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  10. #10

    Default Re: Ground connection in panel

    Quote Originally Posted by Gunnar Alquist View Post
    Thanks Jerry,

    There is a lot there. I am going to have to ponder this a bit.
    In the St Louis area most services are grounded in the basement by the cold water line. On our side of the river almost all ground connections are made by ground rods and connected at the meter. Depends on the POCO.


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