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Discussion in 'High Voltage' started by scarygood536, Jan 8, 2010.

  1. scarygood536

    scarygood536 New Member

    Jan 6, 2010
    Rochester, NY
    Electrical Metallic Tubing (EMT)- A unthreaded thin walled raceway designed for protection and routing of conductors and cables. For use as an equipment grounding conductor when installed appropriate fittings. EMT is generally made of steel with protective coating or aluminum

    Listed Requirements
    EMT, factory elbows, fittings shall be listed by the underwriters Labratory

    EMT is permitted for both exposed and concealed work

    All supports, bolts, straps ,screws shall be corrosive resistant materials

    Uses not permitted

    Where Subject to sever physical damage.

    Protected from corrosion solely by enamel

    In cinder concrete or cinder fill where subject to permanent moister unless protection on all sides by a layer of non-cinder concrete at least 50mm thick or unless the tube is at least 450 under the fill

    In any hazardous location except as permitted by the NEC

    For support of luminaries or other equipment except conduit bodies no larger than the trade size of the tubing

    Dissimilar metals in contact with anywhere in the system shall be avoided to avoid galvanic action


    Minimum- EMT smaller than trade size ½ inch cannot be used

    Maximum-EMT bigger than trade size 4 shall not be used

    Bends- How Made
    Bends shall be made so the tubing is not damage and the internal diameter is not effectively reduced.

    Number of Bends

    There shall not be more than 4 quarter bends (360 degrees) between pull points

    Reaming and threading

    All cut ends of EMT shall be reamed or removed of rough edges

    EMT shall not be threaded

    Securing and supporting

    EMT shall be fastened at least every 10ft

    EMT shall be fastened within 3 ft of each outlet box, junction box, device box, cabinet, conduit body, or any other tubing termination

    Couplings and connectors

    Couplings and connectors shall be made up tight. Where buried in masonry or concrete, they shall be concrete tight


    EMT shall be permitted as an equipment grounding conductor


    Factory threaded integral couplings shall be permitted. The coupling and EMT threads shall be designed so as to prevent bending of the tubing at any part of the tread

    EMT shall be clearly and durably marked at least every 10 ft as required in the first sentence of 110.21

    Attached Files:

  2. tcmtech

    tcmtech Well-Known Member Most Helpful Member

    Feb 22, 2009
    Sawyer, North Dakota, USA
    And this has anything to do with what?

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