Conduit Runs and box wireing

Discussion in 'Electrical Forum discussion & Blog' started by Giles, Feb 19, 2011.

  1. Giles

    Giles Retired tool & Die and Mechanic

    Messages:
    110
    Location:
    N.W. Alabama--Florence--
    I am adding a branch circuit box to a storage room. This box will supply power for a 220v welder and a small 220 4K watt heater. I have noticed that all the 110v wireing is in 1/2" conduit from the celing down.
    Is this required by most codes, and what about "overhead runs"?
    Also, since this box will be mounted in a joining separate room with main breaker panel, what are the grounding rules--since there is no main breaker and no way to bond the ground on the new box?
  2. cacher_chick

    cacher_chick Test, Don't Guess!

    Messages:
    3,239
    Location:
    Land of Cheese
    Wiring must be in conduit where in places where it must be protected from physical harm. Some local codes require conduit throughout.

    I don't understand your question regarding grounding.
    All metal electrical boxes and receptacles must be grounded, be it through conduit and/or a separate ground wire.
  3. Giles

    Giles Retired tool & Die and Mechanic

    Messages:
    110
    Location:
    N.W. Alabama--Florence--
    The box I am installing does not have a main disconnect. It is a QO square D, 6 space #QO6-12L100S. It is my understanding that a sub panel must be bonded and I know how this is done. However there is no way to disconnect the grounds and neutrals as there is only one ground bar. There is a bonding screw.
    I plan to run supply wires from the main panel just as I would if I were adding a 220v recepticle.
    Is this correct?
    I am not new to electrical work but I am not an electrician. I go to the extremes sometimes to make sure it is done correct, and I think that is good.
    THANKS for helping.
  4. drick

    drick In the Trades

    Messages:
    392
    You need a separate ground bar. You can purchase these separately. Just screw one into the back box. There are usually unused screw holes in the back of the box for this purpose and the bar usually includes the screws. The existing bar should be isolated from the box. This is your neutral bar. Just remove the grounding screw from it. Unlike in your main panel neutrals and grounds must be kept separate in a sub panel.

    -rick
  5. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    3,842
    Location:
    NW Ontario, Canada
    In our regulatory domain, I don't believe that metal conduit is adequate for grounding and that a ground wire is required.
  6. jwelectric

    jwelectric Electrical Contractor/Instructor

    Messages:
    2,529
    Location:
    North Carolina
    250.118 Types of Equipment Grounding Conductors.
    The equipment grounding conductor run with or enclosing
    the circuit conductors shall be one or more or a combination
    of the following:
    FPN: For effective ground-fault current path, see 250.2
    Definition.
    (1) A copper, aluminum, or copper-clad aluminum conductor.
    This conductor shall be solid or stranded; insulated,
    covered, or bare; and in the form of a wire or
    a busbar of any shape.
    (2) Rigid metal conduit.
    (3) Intermediate metal conduit.
    (4) Electrical metallic tubing.
Similar Threads: Conduit Runs
Forum Title Date
Electrical Forum discussion & Blog Transition from in-wall to outdoor EMT conduit options? Jun 19, 2014
Electrical Forum discussion & Blog 50A 240vac circuit wire and ground in conduit May 22, 2014
Electrical Forum discussion & Blog Houses built with rigid conduit Sep 1, 2013
Electrical Forum discussion & Blog Can three #8 and one #10 wires be in ½†metal conduit? Aug 1, 2013
Electrical Forum discussion & Blog ground wire in flexible steel conduit - and a de-rating question Jul 26, 2013

Share This Page