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, or

Articles by Charles R. Miller

April 2011
Last month’s article concluded with calculation requirements for new restaurants in accordance with the optional method. This month, the discussion continues with calculating farm loads in accordance with Article 220 in the National Electrical Code (NEC). READ MORE
March 2011
The National Board of Fire Underwriters, which is now the American Insurance Association, published the first edition of the National Electrical Code (NEC) in 1897. In 1911, the National Fire Protection Association (NFPA) assumed sponsorship and control of the NEC. READ MORE
February 2011
The National Electrical Code (NEC) contains nine chapters. The second chapter, Wiring and Protection, is one of four that apply generally to all electrical installations. Some of the articles in Chapter 2 include Article 200—Use and Identification of Grounded Conductors, Article 210—Branch Circuits, Article 230—Services, Article 240—Overcurrent Protection and Article 250—Grounding and Bonding. READ MORE
January 2011
Every three years, the National Electrical Code (NEC) is revised, but the Code has only been on a three-year cycle since 1975. During the NEC’s 114-year existance, revision cycles have ranged from one year to four years. The first edition of the Code book was published in 1897. The newest NEC, the 2011 edition, is the 52nd edition. READ MORE
December 2010
This month, Code in Focus covers an optional feeder and service load calculation for two dwelling units that are supplied by a single feeder. There are two methods for calculating services and feeders for one-family dwellings and multifamily dwellings, and either is permissible. In Article 220, the procedures are covered in Part III for the standard method and in Part IV for the optional method. READ MORE
November 2010
Last month’s Code in Focus covered multifamily-dwelling house loads as calculated in accordance with the optional method. This month, the discussion continues with the connected loads for multifamily dwellings as specified in 220.84(C)(4) of the National Electrical Code (NEC). READ MORE
October 2010
Article 220 of the National Electrical Code (NEC) contains requirements for calculating branch-circuit, feeder and service loads. While understanding load calculation requirements is essential to the professional electrician, knowing what to do with the results from the load calculations is just as important. READ MORE
August 2010
A large number of calculation provisions are in the National -Electrical Code (NEC). Knowing where to find those calculation provisions and how to perform them is essential to electricians, engineers, inspectors and others involved in the electrical industry. READ MORE
July 2010
Load calculation requirements are in Article 220 of the National Electrical Code (NEC). This article contains provisions for calculating branch-circuit, feeder and service loads. Article 220 does not contain all the provisions that must be considered when calculating branch-circuits, feeders and services. Other references found elsewhere in the Code must be considered. READ MORE