Moving Service Meter, supporting issues

Discussion in 'Electrical Forum discussion & Blog' started by D1Case, Jun 27, 2012.

  1. D1Case

    D1Case New Member

    Messages:
    6
    Location:
    Chesapeake, VA
    Hi,

    Looks like I'll be paying the power company a grand just to have a service meter moved/wired to a different side of my house with a 90 ft run. Good Fun. Now I am trying to ensure the correct design the rest of the system.

    As I understand it, I will need to
    - install an external 200A disconnect switch within 5 ft of the new meter.
    - hammer in a new copper grounding pole under the disconnect switch.
    - connect the ground stake to the disconnect ground with a number 4 copper wire.
    - connect the disconnect switch to the old circuit breaker (soon to be called a subpanel) with SER cable (AL 4,2,2,2)
    - install a grounding bar in the sub panel
    - remove the green screw/disconnect the subpanel's old grounding circuit
    - Individual rewire each circuit breaker ground to the grounding bar.

    Is this accurate, and am I missing any details?

    What is the correct running of the SER wire to the disconnect switch? The top two connectors have a green mark, the lower two none, and there are two feeds for a grounding wire.

    I would appreciate it if someone could link pictures of similar work (e.g., Disconnect panels internal wiring, grounding bar installations and wiring, Meter Wiring)

    I would appreciate any recommendations for how to bring the cable/conduit out through the brick wall turning it vertical to the conduit box.

    Is there a best practice size for conduit housing (e.g., 2" elbow/tee against the wall?)

    Once the grounding pole is in the ground, does it require any protection? (The old pole happened to have patched concrete poured on it.)

    Thanks
  2. Homeownerinburb

    Homeownerinburb New Member

    Messages:
    525
    Location:
    Los Angeles, CA USA
    My god, there is a lot there. This is nearly as huge a project as Harry Home Owner is likely to come up against. I cannot claim to be wild about encouraging you to do it.

    But. Come to understand the meaning of a sub panel and the implications for the neutral and ground.

    You only want the neutral and ground bonded in one place in the whole system, and that is at the breaker that is most immediately downstream of the meter, that is your 200 amp disconnect.

    At the original panel the neutrals and the grounds need to be perfectly segregated, and the neutrals need to be isolated from the case of the panel and the ground needs to be bonded to the case of the panel.

    What sort of wire is the house wired with? If it is conduit, then the question of the ground is resolved, you need only find a way to isolate your neutral buss bar from the panel case. Sometimes this is easy, sometimes not. It could be easiest to just mount a new bar with the necessary insulation.

    If your house is wired with NM or MC, then you need to direct all the neutrals to an isolated buss bar and all the grounds to a bonded buss bar. And have the #4 come to this bar, with a large lug if needed to make the connection.

    Are there any large current 240v circuits in the house, like for the range, stove, oven, water heater, ac, etc? Until a few years back it was accepted to mix the ground and the neutral on these, this would be a three wire arrangement. Now we need to provide two hots, a neutral and a ground. The conduit can be the ground, but if you are going to go to this much trouble, do look at this and consider making it modern. If it is in NM, it will be more difficult, you would need to replace it absolutely.

    That is a small fraction of what you are going to be doing.
  3. jwelectric

    jwelectric Electrical Contractor/Instructor

    Messages:
    2,562
    Location:
    North Carolina
    I think you are in over your head.

    I don’t know of any requirement for a disconnect to be within five feet of a meter. The disconnect must be as close as possible to the point where the service conductors enter the building and in some places five feet is as far as they can enter the building but I have never heard of a disconnect being required within five feet of a meter.

    For a 200 amp service your cable is way too small. In fact what you have listed (#2) is only good for 100 amp service.

    You will need more than one grounding “pole” unless you can get an engineer to test the “pole” and sign off that it has 25 or less ohms on a three point test. This will cost more than the utility is charging.

    My only advice that would be worth anything to you would be to get someone local to help you with this installation before you end up wasting a bunch of money.
  4. Jim Port

    Jim Port Electrical Contractor

    Messages:
    156
    Location:
    Maryland
    SER is a cable and does not need to be in conduit. If you are running the conduit for protection reasons, it will be much easier to use individual conductors.

    The grounding electrode will need to be flush or below the surface and have all 8' in contact with the earth.
  5. Homeownerinburb

    Homeownerinburb New Member

    Messages:
    525
    Location:
    Los Angeles, CA USA
    He may well be in over in his head, yes.

    What may be the case is that he has a 100 amp panel but thinks he needs a 200 amp disconnect switch. Who knows? His local home improvement store may only stock a 200 amp disconnect.
  6. D1Case

    D1Case New Member

    Messages:
    6
    Location:
    Chesapeake, VA
    Several Good Posts here, my thanks for your thought and details in the initial responses.

    @ JWelectric, The old system has only one grounding pole, hence my assumption. I appreciate the technical point and hidden challenge supporting your correction. I figure installing a supplemental grounding rod will be easier than testing the resistance of the single driven rod. (btw, it sounds like great advise posted elsewhere in this forum was to attach the clip before pounding.) Assuming the grounding wire starts at the furthest rod, then passes thru the near rod enroute....

    1) How deep should the grounding wire be buried?

    I also really appreciate your assessment of the wire size. I plead guilty to not referencing tables, as my city inspector gave me the 5ft meter distance and initial Wiring size requirement. Regardless, I want to design a system for 200Amp service. (Yes, I never expect to draw that much at any time.)

    2) So is the correct wiring size for 240v Single phase 200 amp: AL 2/0 and/or CU#1 ?

    @Home, I believe I covered my intent to disconnect the old ground in the circuit breaker/soon to be subpanel. Did I word that poorly? Regardless, I agree that the ground will be bonded at the disconnect switch, and the purpose of adding a grounding bar to the old circuit breaker (now subpanel) to separate the grounds from the neutrals.

    @Jim, Yes, the conduit is for protection. At the disconnect box outside the house, the raceway will come out through the brick then run vertical about two feet into the disconnect box. (I also intend to run the raceway through my crawlspace as an unnecessary but practical level of protection.) What I haven't come to terms with, is how to bring it out from the brick. A large radius raceway coming through brick doesn't seem practical, and so I am thinking a junction box would be required to make the turn - but cuts a perfectly good line. So the question/my challenge is...

    3) What is the best/practical way to protect the wire as it comes out of the crawlspace and runs up the wall to the disconnect switch?

    4) Does someone have pictures of a wiring similar to what I am proposing?
  7. jwelectric

    jwelectric Electrical Contractor/Instructor

    Messages:
    2,562
    Location:
    North Carolina
    8 foot rods at least 6 feet apart driven all the way down. The #6 bare copper does not have to be continuous from one rod to the other. You can use two clamps on the first rod, one for the conductor from the panel and the second to the other rod.

    4/0 aluminum or 2/0 copper

    Use a LB to turn up after coming through brick

    Find someone local to give you guidance or plan on spending more money than it would cost to hire the job out. Reinspection fees and tearing out and replacing in order to pass inspection gets costly

    No pictures
  8. D1Case

    D1Case New Member

    Messages:
    6
    Location:
    Chesapeake, VA
    Posting back just to close the loop here. My thanks to each of you for your comments; as you helped both develop the right vocabulary and clarify the picture.
    Lessons learned from this adventure:

    1) Found out that you can get a Power meter with a 200A disconnect built in (after I had roughed in mine.) Simpler, cleaner install. Ah well.
    2) Best Practice (from this website): Attach the clips to the grounding rods before hammering in. (Also dug a hole and filled with water for a couple of days)
    3) I used SER under the house, and protected it in Conduit anyways. It would have been smarter (easier) to do as Jim Port said, and run individual conductors within a conduit. (consider CIC to start with -cable in conduit)
    4) Anti-oxide on cables/fittings.
    5) Removing the Circuit breakers greatly facilitates rewiring the neutrals and grounds, as needed. (Yes my house was wired with NM, fortunately the siemons CB box had two bus bars mostly correctly wired, and I did need that large lug to complete it. Thanks Homeowner inburb!)
    6) I was surprised that I never found any Best Practices on burying depth the copper wire that connected the grounding rods. (creating a mountain out of nothing)
    7) Adding in a 20A circuit to the Moving service permit caused unnecessary delays, as the city didn't tell me but also didnt release the rough in permit to the power company (for moving the service line) because I hadn't laid in the 20A circuit yet.

    Thanks again for all your honest comments.
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