Those who have been following this series of articles for the last year or so may wonder what is involved in designing and installing a code-compliant, durable, reliable, and cost-effective PV system. Utility-interactive photovoltaic (PV) power systems are a mature technology. PV modules have warranties to 25 years and are predicted to produce significant amounts [...]
(No Ratings Yet)
What Is a VFD? A variable frequency drive (VFD) is an electrical device we use to control the speed of a standard three-phase ac induction motor. The number of poles designed into a motor and the frequency applied to the motor determine the motor base speed. We can conveniently adjust the speed of a motor [...]
(2 votes, average: 5.00 out of 5)Welcome to the Rodney Dangerfield of NEC articles! Irrigation machines? Most of you will labor your entire electrical careers without ever having seen one of these, let alone inspect or wire one. Back in 1973, proposal number 115 was submitted to code-making panel 11 by the Technical Subcommittee on Electrically Driven Center-Pivot Irrigator Systems. This [...]
(No Ratings Yet)This article is a continuation of what I see as significant changes that are coming in the 2007 revision of the National Electrical Safety Code.® Direct embedded metal poles as ground electrodes New Rule 094B7 addresses the conditions under which a direct embedded metal pole is considered an acceptable ground electrode.
(No Ratings Yet)
Several of the rules in the Canadian Electrical Code are quite complicated, and it requires our close attention to get them right. This article discusses two of those rules, 28-604 for motor disconnects and 4-004 for underground conductor ampacities. One of the trickiest CE Code rules to follow and interpret correctly is Rule 28-604 Location [...]
(No Ratings Yet)It’s been a long time since someone other than Alan Greenspan has served as chairman of the Federal Reserve Board of Governors. In fact, Greenspan has been at his current job since 1987. But in a few weeks, we’ll see a “changing of the guard” as Ben Bernanke takes the helm at the Fed. This [...]
(No Ratings Yet)
The world’s population, although greater than ever, is also more connected than ever. We are linked by satellite, Internet, fiber optic cables, and high tech communication cords. We transmit data and power in fractions of seconds, often not giving a moment’s thought about the sophisticated technologies that allow these transmissions to take place. Many of [...]
(No Ratings Yet)
Buyers of salvaged, remanufactured, refurbished or new surplus electrical instrumentation for use in hazardous locations (including chemical process plants, refineries, and other industries/applications which are classified as hazardous) need to exercise caution in their instrumentation purchases. Doing so is especially important given the increased market for these items, which experts estimate at $100 million for [...]
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Revisions to the NEC are inevitable, and given the unique and important nature of this electrical safety standard, very necessary. The NEC development process is ever dynamic and ongoing, because new technologies are continuously entering the electrical market and code rules must be developed or revised to address electrical safety concerns related to these new [...]
(No Ratings Yet)Application of certain types of electrical equipment may be governed by codes other than the Canadian Electrical Code (CEC). Emergency lighting and exit signs are good examples of such types of equipment. In fact, the scope of Section 46 of the CEC, Part I states that this section applies to installation, operation and maintenance of [...]
(No Ratings Yet)
IAEI, as the keystone of the electrical industry, is a membership driven, non-profit association promoting electrical safety throughout the industry by providing premier education, certification of inspectors, advocacy, partnerships and expert leadership in Electrical Codes and Standards development.
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