Article 110—Requirements for Electrical Installations
Article 240—Overcurrent Protection
Article 450—Transformers and Transformer Vaults
Working space around electrical equipment
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.
As the Baby Boomers of our society reach their golden years, the need for more and more nursing home facilities will become imperative. Electrical contractors will be faced with the responsibility of properly installing many different sophisticated systems within these nursing homes.
It is possible to ignite combustible gases or vapors either directly from an arc or spark at the electrical equipment or from the heat generated by the electrical equipment, so extraordinary care must be taken when installing electrical equipment in these areas.
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?
The hazardous locations covered by Chapter 5 of the National Electrical Code (NEC) are classified in accordance with the properties of flammable liquids, gases, vapors, combustible dust, or ignitable fibers or flyings that may be present in the area where electrical equipment may be installed.
February’s “Code Question of the Month” column addressed overcurrent device installation in clothes closets. The questions were: (1) May service equipment (overcurrent devices in a panelboard) be installed in a walk-in clothes closet?
Should motor control circuits be grounded? Here are some guidelines:
If a motor control circuit is tapped from the motor circuit and does not leave the controller enclosure (the push buttons are in the cover), then it need not be grounded. [90-7 ¶ 2, 300-1(b), 450-1 Exc.No.2]