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Separate ground for *each* circuit?

Discussion in 'Electronic Basics' started by DaveC, Aug 24, 2003.

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  1. DaveC

    DaveC Guest

    I need to run six 12 ga circuits from the breaker panel to the new
    construction (4 bathrooms).

    Do I need to run one 12 ga ground conductor for each of these circuits? Or
    can I share a single, larger ground conductor between all of them. For
    example, can I run a 10 ga (or larger?) ground conductor and branch that to
    four 12 ga conductors near the load?

  2. Voltaic

    Voltaic Guest

    you dont *need* to run grounds for all 4, but, if weighted correctly, your
    car doesn't *need* 4 wheels. it is imperative to run them for at least 2
    reasons: 1, its a code violation not to (at least in the US). 2: if
    anything ever shorts out or something like that, its always nice to know
    that things are properly grounded and wont be transferring the load of
    power from the short and whatever else is in-line with that one ground.

    people generally rub 3 conductor romex type wire (as i think is actually a
    code requirement) from the breaker panels for "normal" household watages.
    which includes 2 grounds and a hot. anyway, as it is a safety issue, i
    would run the grounds.

  3. Mark or Sue

    Mark or Sue Guest

    It is not a code violation to share a common ground. To use this solution
    you would need to use a raceway (conduit) wiring method. If it is rigid or
    EMT, you can use the raceway as the ground. If PVC or flex, then you run a
    ground sized per the largest circuit being served. In this case, they are
    all 20A, so a single #12 ground is all that is required from the panel. Once
    these circuits begin to split to each bathroom, you need to branch the
    ground too to follow each circuit keeping all conductors together.

    Like Voltaic said, if using NM cable (romex), it will already have the
    grounding wire included in the cable and you can't buy it without it.
  4. Bill

    Bill Guest

    I don't think you can use EMT conduit as a ground. The conduit
    connections aren't good enough to provide the required ground. In EMT
    you have to run a separate ground.

    Bill Gill
  5. CWatters

    CWatters Guest

    In the UK you would run a single cable containing two cores and an earth
    wire in a ring out and back to the board. You get an earth "free" for each
  6. Fred Abse

    Fred Abse Guest

    The UK is unusual in having fused plugs as standard. 13A max in each
    plug, and 30A at the panel for each ring. They're also allowed to spur
    one outlet off each ring outlet. That's why the proposed 16A euro
    standard died, the Brits would need fused outlets and didn't want it.

    Ring circuits are not used much elsewhere in the world. They're actually
    illegal in some places.
  7. Wim Lewis

    Wim Lewis Guest

    If you're trying to reduce the number/size of cables you're running from
    the breaker panel to the new construction, another way is to put in a
    sub-panel somewhere in the new construction. Then you'd run a single
    set of wires (hot + neutral + ground) from your existing box to the new
    one, and the new box would contain six circuit breakers, one for each
    circuit it's supplying.

    There are a bunch of regulations having to do with sub-panels, but if
    the new construction is far away from the existing breaker box, it
    might be worth jumping through the regulatory hoops to put in a subpanel.
  8. One ground, one neutral and one hot. The distinction IS important.
  9. Jim Hancock

    Jim Hancock Guest

    If running conduit and building wire then only one ground is requires for the
    entire conduit regardless of the number of circuits. Ground must be sized for
    the largest circuit in the conduit. 20 amp/12 ga. wire would need one #12
    If you are running any type of cable - NMB, MC, AC - then each would contain
    it's own ground.
    Bathrooms are now required to have dedicated circuits similar to small
    appliance branch circuits in kitchens. Sorry I can't give exact details as my
    code book is not available and I don't do residential.
  10. Guest

    We need more details. Your location will change what rules apply. Is
    this residentail or commercial. Four baths makes me think commercial
    which requires a licenced electricial in most places. Are we talking
    romex or conduit?

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