Article 210 Branch Circuits; Article 230 Services; Article 250 Grounding and Bonding; Article 366 Auxiliary Gutters; Article 422 Appliances; Article 517 Health Care Facilities; Various articles in Chapters 6, 7 and 8 are mentioned.
Many are aware that electrical equipment arcing and sparking -can cause chemical atmospheres (gases, vapors and dusts) to ignite. However, we often forget that thermal ignition of these chemical atmospheres also can occur if the chemicals are exposed to high temperatures.
There are two terms that seem to confuse designers. These terms are “diversity factor” and “demand factor.” To better understand the application of these terms when calculating the load for a service or a feeder supplying a facility, one must understand their meaning.
This article is a continuation of designing and installing electrical systems rated over 600 volts. Note that specific equipment as well as wiring methods and other items that form a complete high-voltage system are discussed.
Selecting switchgear—490.30 through 490.47
Article 110 Requirements for Electrical Installations; Article 250 Grounding and Bonding; Article 300 Wiring Methods; Article 517 Health Care Facilities; Article 547 Agricultural Buildings; Article 695 Fire Pumps; Some parts of the Guide Information for Electrical Equipment Directory (White Book) 20
A requirement for short-circuit current rating was added in the 2005 National Electrical Code (NEC) to Section 430.8 covering motor controller marking, to Section 440.4(B) covering controller marking for air conditioning and refrigerating equipment, and to 409.110 covering controller marking for ind
A faithful reader of ELECTRICAL CONTRACTOR asked how to design and install high-voltage feeders according to the 2008 National Electrical Code (NEC). He requested that I write an article pertaining to such an installation.
A contracting firm I work for is bent out of shape over the new revised Section 210.4(B) and (D) in the National Electrical Code (NEC). The firm, plainly speaking, said this was going to require time to police the trimming out of a panelboard.
Article 220 Branch Circuit, Feeder, and Service Calculations; Article 240 Overcurrent Protection; Article 250 Grounding and Bonding; Article 404 Switches; Article 700 Emergency Systems; Guide Information for Electrical Equipment Directory (White Book) published by Underwriters Laboratories Inc.
I had the privilege of being the guest speaker at a recent contractors meeting, and to my surprise, I was asked an unusual question by a well-known local contractor during the question-and-answer period.
Here's the fourth part of a series reviewing the most popular questions that have appeared in NECA’s online Code Question of the Day and have generated the most comments from subscribers. All answers are updated to comply with the 2008 National Electrical Code (NEC).
Emergency circuits are installed in patient bed locations in general care and critical care areas in hospitals to ensure power is available to electrical equipment even where normal power is lost for some reason.