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Thread: installer cut off the #4 ground on the SER

  1. #1
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    installer cut off the #4 ground on the SER

    Hi everybody...

    I replaced two 2-2-2-4 SER with 2/0-2/0-2/0-4 & 1/0-1/0-1/0-4 to get 125A in each unit for a two-family. The upstairs SER was de-rated for attic heat & length. I have a 2 gang Siemens WP2211RJ gang meter and a 200A panel (P4040B1200CU) back fed with a 125A breaker and a 125A lug panel (P2020L1125CU).

    I paid an installer to do this work. He cut the #4 ground off both SER's at the meter end, over my objections, saying they were redundant. He connected the SER neutrals to the grounded neutral from the POCO. The units were energized & everything appears OK. But I'm worried about those cut grounds.

    The units are empty and I don't want to get tenants in them until I determine if this setup is safe. In the last two days, I've read a lot about earth ground, equipment ground, bonding, etc.

    At first, I thought the following after reading the NEC and looking at the (1st picture) of EGC bonded to neutral:

    250.130 Equipment Ground connections at service equipment shall be made as indicated in 250.130(A) or (B).
    (A) For Grounded Systems. The connection shall be made by bonding the equipment grounding conductor (i.e., the unsheathed SER ground cable) to the grounded service conductor (i.e., the grounded neutral from utility company) and the grounding electrode conductor (i.e., the earth ground).

    since my gang meter is grounded to earth, the EQPT GND on the SER needed to be connected to the grounded service neutral conductor and the bond between the neutral & ground should be removed at each panel.

    if the gang meter were not grounded, then the EQPT GND on the SER still should have been attached to earth ground but the bond between the neutral & ground at each panel would remain intact and each individual panel should be connected to an earth ground.

    BUT THEN, I saw the 2nd picture on Mike Holt's site of neutral to case connection and read the following:

    "At service equipment, the service neutral conductor provides the effective ground-fault current path to the power supply [250.24(C)]; therefore, an equipment grounding conductor isn't required to be installed within PVC conduit containing service entrance conductors [250.142(A)(1) and 352.60 Ex 2]."

    So, if the gang meter is service equipment and the installer connected the SER neutral to the grounded neutral from the POCO, is what he did OK?? It looks exactly like the 2nd picture. (My understanding is the service equipment comes bonded from the manufacturer.)

    Can somebody shed some light on this for me please? I need to either move on or get this fixed ASAP.

    thank you
    cubgirl
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    Does the meter pan contain the main breakers for the units?

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    The grounded [neutral] conductor is used for bonding (i.e. grounding) on the utility side of each service disconnecting means. Most residential service entrance conductors are run in SEU.


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    FWIW, most jurisdictions would not permit you to run service entrance conductors through an attic. To me, that indicates this run would be on the consumer side of a service disconnecting means, and requires an EGC. Theses feeder conductors are typically run in SER, with separate grounded [neutral] conductor and equipment grounding conductor.
    I will have achieved my life's goal if I die with a smile on my face.

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    Quote Originally Posted by Cow View Post
    Does the meter pan contain the main breakers for the units?
    yes, it's siemen's WP2211RJ...
    Attached Images Attached Images  

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    Quote Originally Posted by Smart $ View Post
    FWIW, most jurisdictions would not permit you to run service entrance conductors through an attic.
    then what are derated feeders? one reason you derate is because of ambient temperature. the lug panel is upstairs & its feeder goes through an attic. the cable was derated for heat.

    AHJ already ok'd it but our AHJ is a joke in my opinion...

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    Quote Originally Posted by Smart $ View Post
    To me, that indicates this run would be on the consumer side of a service disconnecting means, and requires an EGC. Theses feeder conductors are typically run in SER, with separate grounded [neutral] conductor and equipment grounding conductor.
    i'm a retired engineer, NOT AN ELECTRICIAN, which is probably obvious, yuk yuk

    but in the neutral to case picture, the SER, going into the service equipment disconnect, does not have a ground. i'm assuming the other end of the SER is connected to load equipment. so the SER is not grounded at the service disconnecting equipment in this case. and according to NEC 250.142, this is OK.

    i'm trying to figure out this earth ground, EQPT GND, bonding stuff. from what i gather on the web, there's a lot of confusion on these topics.

    thanks
    Last edited by cubgirl; 05-20-16 at 03:59 PM.

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    The picture shows what's called a meter-main. Meters on the right, and service conductors enter on the right. POCO puts a seal on the locking mechanism. There is manufacturer-installed internal bus or wiring connecting the meters to the breakers in the left compartment. The breakers are the service disconnecting means. Anything connected to the load side of those breakers requires a separate grounded [neutral] conductor and equipment grounding conductor. Your installer is wrong.
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    ok, that's what i'm hearing... i take it that the SER is not grounded (except neutral to grounded service neutral) and the SER is also considered on the load side, not the supply side?

    with that in mind, i find this in the code:

    250.142 Use of Grounded Circuit Conductor for Grounding Equipment

    B) Load Side Equipment
    Except as permitted in 250.30 (A) (1) and 250.32 (B) a grounded circuit conductor shall not be used for grounding non-current-carrying metal parts of equipment on the load side of the service disconnecting means or on the load side of a separately derived system disconnecting means or the over current devices for a separately derived system not having a main disconnecting means.

    Exception No 2) It shall be permissible to ground meter enclosures by connection to the grounded circuit conductor on the load side of the service disconnect if
    a) No service ground fault protection is installed and
    b) All meter enclosures are located near the service disconnecting means and
    c) The size of the grounded circuit conductor is not smaller than the size specified in Table 250 122 for equipment grounding conductors

    how do i know exception #2 does not apply to this scenario?

    sorry for not "getting it" faster but the code is confusing.

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    Quote Originally Posted by cubgirl View Post
    ...
    how do i know exception #2 does not apply to this scenario?
    Because your meters are not on the load side of the service disconnects.

    sorry for not "getting it" faster but the code is confusing.
    No problem. Code can be confusing for even the most knowledgeable tradespersons.
    I will have achieved my life's goal if I die with a smile on my face.

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