Charles R. Miller

Code Contributor

Charles R. Miller, owner of Lighthouse Educational Services, teaches classes and seminars on the electrical industry. He is the author of “Illustrated Guide to the National Electrical Code” and NFPA’s “Electrical Reference.” He can be reached at 615.333.3336, charles@charlesRmiller.com or www.charlsRmiller.com

Articles by Charles R. Miller

April 2012
One of the most-referenced tables in the National Electrical Code (NEC) is Table 310.15(B)(16), formerly Table 310.16. It contains allowable ampacities of insulated copper and aluminum (or copper-clad aluminum) conductors rated up to and including 2,000 volts (V). The temperature ratings of conductors include 60°C (140°F), 75°C (167°F) and 90°C (194°F). READ MORE
March 2012
Selecting the correct size conductor is not a difficult task, but there is more to it than just picking a conductor from Table 310.15(B)(16) in the National Electrical Code (NEC). The conductor must be selected and installed in accordance with all applicable provisions pertaining to conductors. READ MORE
February 2012
When sizing conductors, the number of current-carrying conductors installed in a raceway or cable must be considered. No conductor shall be used in such a manner that its operating temperature exceeds that which is designated for the type of insulated conductor involved [310.15(A)(3)]. READ MORE
January 2012
Table 310.15(B)(16) (formerly Table 310.16) in the National Electrical Code (NEC) provides allowable (or maximum) ampacities for insulated conductors rated up to and including 2,000 volts (V). The allowable ampacities in this table are based on two stipulations: adjacent load-carrying (current-carrying) conductors and ambient temperature. READ MORE
December 2011
Allowable ampacities for insulated conductors rated up to and including 2,000 volts (V) are in Table 310.15(B)(16). This table underwent a number change in the 2011 edition of the National Electrical Code (NEC). Before, this table was numbered 310.16. READ MORE
November 2011
Safety is the main reason for the existence of the National Electrical Code (NEC). Its purpose is the practical safeguarding of persons and property from hazards arising from the use of electricity [90.1(A)]. Ensuring conductors and overcurrent protective devices are sized correctly is one aspect of practical safeguarding. READ MORE
October 2011
The National Electrical Code (NEC) is revised every three years. The renumbering of Table 310.16 to Table 310.15(B)(16) was a significant change in the 2011 edition. READ MORE
September 2011
Sizing conductors is not a difficult task, but more is involved than referencing just one section, one article or even one chapter in the National Electrical Code (NEC). To select the correct conductor size, it is necessary to reference several sections throughout the Code. Before referencing the NEC, certain information is needed. Gather it by answering some key questions. READ MORE
August 2011
Whether conductors are supplying power to branch circuits, feeders or services, the ampacity must not be less than the load. The load can be an actual load, or it can be calculated in accordance with the requirements in Article 220 of the National Electrical Code (NEC). READ MORE

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