Article 394 Concealed Knob-and-Tube Wiring

Article 394 Concealed Knob-and-Tube Wiring

I. General

This type of wiring is a single insulated conductor using knobs , tubes, and flexible nonmetallic tubing for support and protection.

II. Installation

It can be used only to extend an existing installation or elsewhere with special permission from the authorities having jurisdiction and in hollow spaces of walls and ceilings and unfinished attic and roof spaces (refer to Section 394.23 in the NEC ).

394.12

Uses Not Permitted

It is not allowed in commercial garages, motion picture studios , classified hazardous locations, theaters and similar locations, or in hollow spaces of walls, ceilings, and attics under certain conditions.

394.17	Through or Parallel to Framing Members
394.19	Clearances
394.23	In Accessible Attics
394.30	Securing and Supporting
394.42	Devices
394.56	Splices and Taps

III. Construction Specifications

394.104

Conductors

Article 396 Messenger Supported Wiring

I. General

This type of wiring is exposed using a messenger wire as a support for insulated conductors. These conductors are usually in the form of a type of cable. In some instances in industrial establishments, insulated wire can be used as well as cable.

II. Installation

Article 398 Open Wiring on Insulators

I. General

This type of wiring is exposed with a single insulated conductor using an insulator (knob, cleat, tube, or flexible tubing) for protection and support.

II. Installation

This type of wiring can be used only where the nominal voltage does not exceed 600 V, in industrial or agricultural structures, both indoors and outdoors, both wet and dry locations, for services, and where corrosive vapors are present.

398.12

Uses Not Permitted

Cannot be used if concealed by the building structure.

398.15	Exposed Work
398.17	Through or Parallel to Framing Member
398.19	Clearances
398.23	In Accessible Attics
398.30	Securing and Supporting
398.42	Devices

III. Construction Specifications

398.104

Conductors

4. Equipment for General Use

Article 400: Flexible Cords and Cables

Article 402: Fixture Wires

Article 404: Switches

Article 406: Receptacles, Cord Connectors, and Attachment Plugs (Caps)

Article 408: Switchboards and Panelboards

Article 409: Industrial Control Panels

Article 410: Luminaires (Lighting Fixtures), Lampholders, and Lamps

Article 411: Lighting Systems Operating at 30 Volts or Less

Article 422: Appliances

Article 424: Fixed Electric Space Heating Equipment

Article 426: Fixed Outdoor Electric De-Icing and Snow-Melting Equipment

Article 427: Fixed Electric Heating Equipment for Pipelines and Vessels

Article 430: Motors, Motor Circuits, and Controllers

Article 440: Air Conditioning and Refrigerating Equipment