Electical Contractor

210-5 Identification for Branch Circuits

Recently, a new term has evolved to describe an integration of all low-voltage systems, such as TV, radio, telephone, and Internet/computer interlinks from one main distribution hub to serve all rooms within a building with multifunction communications capability.

CODE CITATIONS Article 110—Requirements for Electrical Installations Article 210—Branch Circuits Article 250—Grounding Article 430—Motors, Motor Circuits, and Controllers Article 517—Health Care Facilities

Continuing with our review of taps from branch circuits, Sec. 210-19 and from feeders, Sec. 240-21(b) and (c), we turn now to 240-21(d), which is a reference to Sec. 230-91, Service Conductors.

CODE CITATIONS Article 240—Overcurrent Protection Article 250—Grounding Article 430—Motors, Motor Circuits, and Controllers Article 440—Air-Conditioning and Refrigeration Equipment Article 680—Swimming Pools, Fountains, and Similar Installations Overcurrent protection

Last month we discussedSection 240-21 tap rules, and the effectiveness of the overcurrent protection for the tapped conductors. Sec. 240-21(b)(4) Taps Over 25 ft.

Sizing requirements for boxes and conduit bodies used as pull or junction boxes are stipulated in Section 370-28. While the boxes within the scope of 370-16 are calculated from the sizes and numbers of conductors, boxes in 370-28 are calculated from the sizes and numbers of conduits (raceways).

Does the National Electrical Code (NEC) require all lighting installations operating at 30 volts or less to be Listed systems? Can individual low-voltage lighting components, such as a power supply, fixtures, and conductors be assembled in the field without being part of a Listed system?

370-28(a)(2) Angle Pulls