I made a comment while teaching a class that nonmetallic (NM) cable was not permitted in an outdoor, wet location. An attendee took exception to that statement and asked me to provide National Electrical Code (NEC) justification for the assertion.
Editor’s note: Jim Dollard is our new Code FAQs columnist. While he has big shoes to fill after Charlie Trout’s retirement, he has an extensive background in codes and standards. He also has a new email address for you to send in your questions: email@example.com.
The 2014 National Electrical Code (NEC) process received more proposals—including a total of 45 generated by the NEC Correlating Committee Task Group on direct current (DC)—and comments to insert DC into the Code than any other NEC cycle in history.
This article is a continuation of a concise and complete review of some of the more significant changes that have been incorporated into the 2014 edition of the National Electrical Code (NEC). This segment takes a look at some significant revisions in chapters 4 through 6.
Many buildings and structures are supplied by power from a source other than a utility service. If the supply—such as a transformer or generator—is customer-owned, it is not a service and, therefore, is either a feeder or branch circuit.
Article 240 in the National Electrical Code (NEC) is titled “Overcurrent Protection.” While this term is not defined, Article 100 defines overcurrent. Overcurrent is any current in excess of the rated current of equipment or the ampacity of a conductor.
A friend of mine recently called with a question about the cover depth requirement for an underground 120-volt (V) lighting circuit installation in rigid polyvinyl chloride (PVC) conduit supplying a wet-niche luminaire in a swimming pool.
Part I of this series reviewed some Code-wide revisions and some of the significant changes in Chapter 1 of the National Electrical Code (NEC). This segment takes a look at some significant revisions in chapters 2 and 3 (with the comment or proposal number cited after each listing).
Section 240.21 in the National Electrical Code (NEC) contains feeder tap rules. As defined in 240.2, a tap conductor has overcurrent protection ahead of its point of supply that exceeds the value permitted for similar conductors that are protected as described elsewhere in 240.4.
As we enter the fall, crops are ready for harvest, the leaves on trees are turning color, the evenings have a slight chill, baseball season is nearing an end, football season is just getting started, and we have a new 2014 National Electrical Code (NEC).
I was involved recently in a discussion on lightning protection for various types of buildings and what standards applied to those installations or if the installations required compliance with NFPA 780, Standard for the Installation of Lightning Protection Systems; UL 96A, Standard for Installation
Table 310.15(B)(16) is one of the most referenced tables in the National Electrical Code (NEC). It contains allowable (or maximum) ampacities for insulated conductors rated up to and including 2,000 volts (V). The ampacities listed in this table are based on specific conditions.
If you have a problem related to the National Electrical Code (NEC), are experiencing difficulty in understanding a Code requirement, or are wondering why or if such a requirement exists, ask Charlie, and he will let the Code decide. Questions can be sent to firstname.lastname@example.org.