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IAEI Magazine | Author: Christel Hunter
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Christel Hunter

Christel Hunter, senior engineer, Alcan Cable. Chris holds bachelor of science degrees in engineering physics and electrical engineering and a masters in business administration. She has worked in the electrical industry for sixteen years including positions with the utility, regulatory and manufacturing sectors of the industry. Chris serves on NEC CMP-6 and CMP-7, CEC Section 4, chair of CANENA THSC20, and many other industry committees. She is an associate certified standards engineer, master electrician and LEED accredited professional.


Working Space for Electrical Equipment

Electrical systems are typically given a great deal of consideration during the design and installation phase of new construction or major renovation, but very little thought after completion — until something fails. Even though our electrical systems are usually very reliable, it is likely that some components will need maintenance or testing at some point in the life of the building or structure. Therefore, the NEC contains requirements meant to allow for safe and practical access to electrical equipment after the time of installation.

Residential Service Calculations in the National Electrical Code

Load calculations in the National Electrical Code have evolved over many decades. It was in the 1933 NEC that load calculation requirements began to resemble a format that the modern code user would find familiar. Since then, many things have changed, but the primary requirement remains the same — service equipment and conductors must be sized to handle the expected load.

Are You the Weakest Link?

Good workmanship requires that the professional electrician make sure that equipment is suitable for the installation and used in ways that comply with applicable codes and job requirements. Since most electrical equipment must be physically connected by some form of conductor, those connections are critical to the long-term reliability and safety of the installed electrical system. Developing good connection techniques and understanding what makes a good connection are the hallmarks of a professional electrician.

Electric Vehicle Charging

Car buyers who wish to take advantage of new technology electric vehicles — either battery electric vehicles or plug-in hybrid vehicles — have several choices. With no additional electrical system upgrade to their home, battery electric vehicles and plug-in hybrid electric vehicles can be charged using a standard 120-volt, 20-amp receptacle. This is referred to as Level I charging. Unfortunately, a full charge at this voltage can take quite some time, generally estimated at 8–20 hours. If a shorter charge time is desired, a 240-volt charging station can be installed which cuts charge time approximately in half. This is referred to as Level II charging, and connections are achieved using a standardized connector manufactured to SAE J1772. For an even faster charge, Level III chargers operate at 480 volts and can charge a vehicle in less than half an hour; these are presently rare, not fully standardized and only available in non-residential locations.

Electrically Charged Public Transportation

In 1996, a new Article 625, Electric Vehicle Charging System Equipment, was added to the National Electrical Code (NEC) in anticipation of new technology in the form of electrically charged vehicles. The addition of this article was in response to clean air legislation on both the federal and state level that implemented new requirements for vehicles with reduced emissions of air pollutants. Article 625 (titled Electric Vehicle Charging System in the 2008 NEC) includes requirements for "…electrical conductors and equipment external to an electric vehicle that connect an electric vehicle to a supply of electricity…” and the installation of the related equipment and devices.

The Difference between Success and Failure — How a Torque Wrench Improves System Reliability

In NASCAR, pit crew members use impact wrenches with preset torque values to install lug nuts during a wheel change. A loose lug nut can mean the difference between winning and losing, as Greg Biffle found out in 2005 when loose lug nuts on the left rear tire caused vibration and forced him to take an extra pit stop at the Texas Motor Speedway. Biffle lost a lap and finished 20th, which cost him enough points to lose the Chase for the Nextel Cup to Tony Stewart. No race car driver or their pit crew would question the importance of using the proper tool and the proper torque on lug nuts. Yet many electricians go to work every day and tighten electrical connections with no more than a folding Allen set.

Medium Voltage Seminar

The Southern Nevada Chapter of IAEI sponsored a Medium Voltage seminar on August 25, 2007. It was held at the Clark County Development Services Center and instruction was provided by Mike Johnston (IAEI) and Chuck Mello (UL). Mike and Chuck developed the course on behalf of the IAEI at the request of Rick Maddox, international third vice-president of the IAEI and building inspections supervisor with Clark County, Nevada.

Aluminum Building Wire Installation and Terminations

Electricity is transmitted from the utility generating station to individual meters using almost exclusively aluminum wiring. In the U.S., utilities have used aluminum wire for over 100 years. It takes only one pound of aluminum to equal the current-carrying capacity of two pounds of copper. The lightweight conductors enable the utility to run transmission lines with half the number of supporting structures. The utility system is designed for aluminum conductors, and utility installers are familiar with installation techniques for the types of aluminum conductors used in utility applications.