Mark C. Ode

Fire/Life Safety Columnist and Code Contributor

Mark C. Ode is a staff engineering associate at Underwriters Laboratories Inc., based in Peoria, Ariz. He can be reached at 919.949.2576 and

Articles by Mark C. Ode

  • Littelfuse Shock-Block Class C and D GFCI
February 2015
I recently taught a 2014 National Electrical Code (NEC) class at an industrial facility in Fort Wayne, Ind., where an attendee asked about special-purpose ground fault circuit interrupters (GFCIs) with trip levels above the normal 4­–6 milliampere (mA) trip threshold level. I told him that the definition of GFCI in the 2014 NEC only recognizes a Class A device. READ MORE
January 2015
Many of the articles I write for ELECTRICAL CONTRACTOR originate as questions from people who read my columns or attend my workshops. This article is based on a question from an electrical contractor friend who is doing an electrical installation in an extremely large hangar being used for painting aircraft. READ MORE
December 2014
Some photovoltaic (PV) inverter manufacturers have designed and built transformer-less inverters to add to their existing line of transformer-type inverters for installation in the United States. Transformer-less inverters have been popular in Europe for quite some time. READ MORE
November 2014
I recently was asked to review a series of emails from a colleague about equipment requirements for ready access or, as defined in Article 100 and used within text in the National Electrical Code (NEC), as “readily accessible.” This phrase is used to describe the location of circuit breakers, for example, permitting ready access to turn the circuit off during times of emergency, when something mal READ MORE
October 2014
A recent change in the 2014 National Electrical Code (NEC) creates a new method for determining the size of service and feeder conductors for 120/240-volt (V), single-phase services for one-family, individual units of two-family dwellings, and individual units for multifamily dwellings. READ MORE
September 2014
My last article provided a history and background on Article 400, dealing with flexible cords and cables. This month, I delve further into whether flexible cords and cables could or should be installed in concealed locations. Does the National Electrical Code (NEC) already permit concealed installations, and, if so, why are these applications acceptable while others are not? READ MORE
August 2014
Concealment of flexible cords and cables that are installed as an integral part of appliances—or when used for connecting other electrical equipment—is an ongoing issue for the electrical industry. The history of the National Electrical Code (NEC) provides some insight.
July 2014
The concept of modular data centers (MDCs) originated about six or seven years ago as a portable method of delivering information technology data center capacity without the high cost and long construction time. Manufacturing these data centers at a factory can reduce fabrication cost and time as well as facilitate shipping using a train, truck or a combination of both. READ MORE
June 2014
NFPA 70, the National Electrical Code (NEC), is an installation code, while NFPA 70E is the Standard for Electrical Safety in the Workplace. There is an unofficial line of demarcation between the two documents. The NEC is used for design, installation and inspection of the electrical installation before the system is energized. READ MORE