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IAEI Magazine | Author: Michael Johnston
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Michael Johnston

Michael Johnston is NECA’s executive director of standards and safety. Prior to working with NECA, Mike worked for the International Association of Electrical Inspectors as the director of education, codes and standards. Mike is a member of the IBEW and has experience as an electrical journeyman wireman, foreman and project superintendant. Mike achieved all electrical inspector certifications through IAEI and ICC and has worked as an electrical inspector and electrical inspection field supervisor for the city of Phoenix, AZ. Mike achieved a B.S. in business management from the University of Phoenix. Mike is the chairman of the NEC Correlating Committee and served on NEC CMP-5 in the 2002, 2005, 2008, and chair of CMP-5 representing NECA for the 2011 NEC cycle. Johnston is an active member of ANSI, IAEI, NFPA, ASSE, the NFPA Electrical Section, Education Section, the UL Electrical Council, and National Safety Council..


Articles

Energy Alternatives and NEC Implications

The world is changing rapidly and becoming more dependent than ever on expanded use of alternative energy systems and reducing and preserving grid-produced energy. The electrical infrastructure in the United States is one of the best in the world, but is aging and, to some degree, becoming more vulnerable to the effects of aging and loading. Society is typically not removing loads from the electrical grid, but is adding load.
JULY-AUGUST 2012

Safely Harnessing the Sun’s Energy

Across the country and around the world, harnessing energy from the sun is becoming increasingly achievable for homeowners, businesses, and utilities alike. With an increased interest in solar photovoltaics (PV), comes a plethora of opportunities, as well as some challenges for the electrical industry. Amidst all the excitement and advantages of getting connected to alternative energy sources, the same safety hazards to persons and property should be realized by electrical industry partners, and more importantly, by consumers.
MARCH-APRIL 2010

Electrical Workmanship Standards (NEIS) — A Benchmark of Quality

In 1996 the National Electrical Contractors Association (NECA) ventured into a major effort to develop electrical installation standards for the electrical contracting industry. The initial effort included the development of NECA 1 Standard for Good Workmanship in Electrical Contracting. This first NECA standard serves as the flagship standard and the foundation for this family of quality and performance standards.
SEPTEMBER-OCTOBER 2009

Bonding Metal Gas Piping

Many questions are being raised about the requirements for bonding metal gas piping systems. More specifically, when corrugated stainless steel tubing (CSST) is installed for the gas piping in a building, bonding methods and bonding jumper sizes that are more restrictive than required by the National Electrical Code® are causing some of the confusion...
JULY-AUGUST 2009

Focus on the Code: Protect grounding electrode conductor in crawl?

You are correct in your understanding of this rule. The last sentence of 250.64(B) requires an 8 AWG copper grounding electrode conductor to be protected from physical damage by installing it in rigid metal conduit, rigid nonmetallic conduit, intermediate metal conduit, electrical metallic tubing, or cable armor, and no exceptions to this requirement.
JANUARY-FEBRUARY 2009

Focus on the Code: Is an additional bare copper bonding wire jumper required?

Your question deals with use of the grounded conductor for grounding and bonding on the supply side of the service disconnecting means. Your understanding is correct. The grounding conductor is permitted to be used for grounding and bonding on the supply side of the service disconnecting means. The grounded (neutral) conductor is required to be routed between enclosures and bonded to both, and this is common practice. The supporting NEC references are 250.92(B)(1) and 250.142(A)(1).
SEPTEMBER-OCTOBER 2008

Focus on the Code: Size of bonding wire for 200-amp load center

The question appears to deal with a voltage-drop situation, but information is missing. I will answer the question by inserting the minimum necessary information. The first item to clarify is the terminology. I presume you are referring to the size of the equipment grounding conductor with the feeder and not a bonding wire which is undefined by the NEC. The next bit of information needed is the size of the ungrounded phase conductors intended to be installed for this feeder.
SEPTEMBER-OCTOBER 2008

Focus on the Code: Can you daisy chain connections to fixtures?

This response is based on the information provided in the question. 2 x 4 lay-in style fluorescent luminaires are permitted to be wired with any branch circuit wiring method in chapter 3 of the NEC, depending on the type of building construction it is being installed in. You indicated that the luminaires are being wired using MC cable that is run from one luminaire to the next, using the ballast compartment as a junction box.
JULY-AUGUST 2008

Focus on the Code: Static Electricity and UL 971

This message is in response to your request for information about static electricity issues when plastic piping is used for transport. This subject is beyond the scope of NEC requirements. Often UL Standards writing has input from industry professionals that have expertise in a given field to attain the most meaningful input and to work on developing comprehensive product safety standards.
JULY-AUGUST 2008

Equipment Grounding for Safety

Electrical systems and equipment are grounded to achieve a greater level of safety from electrical hazards to persons and property. Article 250 of the NEC provides the minimum requirements for grounding and bonding electrical systems and equipment. NEC-2008 has incorporated revisions related to electrical grounding and bonding terminology that results in improved clarity and usability.
MARCH-APRIL 2008

At Risk Below the Minimum

The NEC contains the minimum requirements for electrical installations to ensure they are essentially free from hazards. Compliance with the NEC rules means meeting minimum safety requirements established by qualified technical committees that respond to compelling reasons (substantiation) that result in the minimum requirements.
NOVEMBER-DECEMBER 2007

Strengthening Alliances in Training

IAEI has the principal mission of promoting electrical safety, a mission supported by the work and responsibility of the inspector. Many of the different entities in the electrical industry that strive to achieve safety by diligently carrying out their responsibilities have discovered that training is a key factor in achieving safe electrical installations.
SEPTEMBER-OCTOBER 2007

Electrical Inspection Is Indispensable for Electrical Safety

It is essential for safety that jurisdictions establish and maintain an effective code enforcement program. Inspections of installed work provide an opportunity to identify and correct potential hazards, such as shock, electrocution, fire and others, before some catastrophe occurs. Other benefits of code enforcement and building inspections are the positive affects on insurance rates and the reduced number of fires and injuries.
SEPTEMBER-OCTOBER 2007

Isolated Power Systems in Health Care Facilities

Grounded Systems Generally Required Generally, electrical systems used in power distribution systems for premises wiring are required to be grounded. The NEC includes rules that often make this determination. Some electrical systems are required to be grounded, while other systems are permitted to operate ungrounded (see 250.20 and 250.21).
JULY-AUGUST 2007

When Disconnects Are Not Enough

May is electrical safety month, during which the electrical industry draws attention to all aspects of electrical safety for persons and property. Section 90.1(A) of the NEC provides the essence and basis for this concept that is integral to the rules in the Code.
MAY-JUNE 2007

Getting Down to Earth

From the beginning, the National Electrical Code has included specific rules that are essential for protection of persons and property. Wiring and protection is covered more specifically in chapter 2 and is so titled. Article 250 provides the specific rules for grounding and bonding electrical systems and equipment.
MARCH-APRIL 2007

Equipment Grounding Conductors for Parallel Conductor Installations

Equipment installed in electrical systems generally is required to be grounded. There are some specific exceptions that relax this general requirement of the NEC; but, for the most part, electrical equipment and the normally non-current-carrying metal (conductive) parts of equipment are to be grounded.
JANUARY-FEBRUARY 2007

The Value of Electrical Inspection

There is significant intangible value in many of the things we take for granted. For example, essential resources such as the air we breathe and the water we drink and use are often taken for granted. Society expects these life essentials to be safe, and not much thought is given to how safe they really are. Only when an identified problem surfaces, do people get concerned and fear sets in.
NOVEMBER-DECEMBER 2006

Analysis of Changes, NEC-2008, Part II

In the July/August issue, we provided a glimpse of some of the more significant changes proposed and accepted for NEC-2008. This article is a continuation of that review. Once again, it is important to stress that this is a look at what was proposed and acted on by the code-making panels through the proposals stages of the NEC-2008 development process. These changes could be affected by public comments to the initial committee actions on these proposed revisions. The established deadline for public comments to the proposed changes is October 20, 2006 (5:00 p.m. est).
SEPTEMBER-OCTOBER 2006

Analysis of Changes, Part 1, NEC-2008

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 materials, equipment, emerging methods or technologies. There were 3,688 proposals, including all technical committee proposals, to change NEC-2008. These proposed changes were acted on by the technical committees at the Report on Proposals (ROP) meetings held in January 2006. This article provides an overview based on code-making panel actions taken on the proposals in the first stage of the development process.
JULY-AUGUST 2006

Current in the Grounded Conductor

Recently there have been several questions about the locations of grounding connections to the grounded conductor. Before looking at some of the requirements specific to grounding locations and the reasons behind those rules, let’s review some basic rules that apply to the grounded conductor. I guess the first thing that should be pointed out is that the grounded conductor is often a service or system neutral conductor. For the purposes of this article we’ll address this conductor as the grounded conductor.
MAY-JUNE 2006

Isolated Grounding Receptacle Circuits – Got Clean Grounds or Dirty Grounds?

Clean power is the objective, but what about noise on the equipment grounding conductor and other grounding paths? How "clean” is your isolated (insulated) equipment grounding circuit? Chances are if you’ve been involved in the electrical field, you’ve had experiences either installing or inspecting isolated (insulated) equipment grounding circuits and receptacles.
MARCH-APRIL 2006

The Inspector’s Approval

In some previous issues of IAEI News, articles about some of the many "hot spots” in the electrical inspection process were identified and detailed. There are a vast number of areas in the Code where the electrical inspector or building inspector has to operate out of his or her comfort zone. Qualifications of inspectors are very important. A couple of the most important characteristics or "traits of a good inspector” are knowing when to ask questions, and knowing what questions to ask. This article takes a closer look at the electrical inspector and the process of approving an electrical installation and the associated equipment. It’s a big responsibility for the inspector and the jurisdiction, but it is often taken for granted by both.
JANUARY-FEBRUARY 2006

Bonding Metal Piping Systems

Article 250 of the National Electrical Code provides the minimum requirements for grounding and bonding. The title of the article was revised in the 2005 NEC development process to reflect what is actually covered by the article.
NOVEMBER-DECEMBER 2005

Concrete-Encased Electrodes Required

Part III of Article 250 provides the important concept of a grounding electrode system, where all grounding electrodes are required to be bonded together and function as a system as indicated in Section 250.50. Rather than reliance on a single grounding electrode to perform its function over the life of the electrical installation, the NEC requires the formation of a system of electrodes "that are present at each building or structure served.” There is no doubt that building a system of electrodes adds a level of reliability and helps ensure system performance over a long period of time, usually the duration of the life of a building or structure. It is important to understand that this requirement applies generally to all buildings or structures and is not limited in application to just commercial or industrial installations. Residential construction is included in these requirements.
SEPTEMBER-OCTOBER 2005

Grounding Separately Derived Systems

Separately derived systems can be grounded or ungrounded. The primary difference between a grounded derived system and an ungrounded derived system is that no intentionally grounded system conductor exists in an ungrounded system. All conductors derived from these systems are ungrounded conductors. Where the separately derived system is required to be grounded as provided in 250.20(A) or (B), it must be grounded in accordance with the rules in 250.30(A). Ungrounded separately derived systems must be grounded in accordance with 250.30(B). This article provides a concise review of the rules for grounded separately derived systems and some application examples.
JULY-AUGUST 2005

Emergency Systems and the Witness Test

Emergency systems in buildings or structures can vary in size and complexity. Some basic emergency systems provide illumination of the egress paths through unit equipment connected to local area lighting circuits. Other more complex and multiple function emergency systems provide power not only for lighting for the egress path but for many other essential functions, such as smoke control systems, life support systems, fire pumps, life support systems and equipment, etc.
MARCH-APRIL 2005

Inspection Basics for Electrical Signs and Outline Lighting

When making an inspection on an electric sign or field-installed skeleton tubing installation, where does one begin? Well, there are undoubtedly several answers to that question from the many inspection jurisdictions charged with the task of adopting and enforcing the requirements of the electrical Code. Experience has indicated that there are a wide variety of approaches to conformance assessment of these electrical signs and displays, or other types of outline lighting, falling under the scope of the adopted Code.
MARCH-APRIL 2005

Under the Watchful Eye of the Inspector – Hot Spots

Electrical inspectors as well as building inspectors have important roles in assuring safety for persons and property. It is essential for safety that jurisdictions establish and maintain an effective code enforcement program. Inspections of installed work provide an opportunity for potential shock hazards, electrocution, fire and other hazards to be identified and corrected before the occurrence of such sad and unnecessary events.
JANUARY-FEBRUARY 2005

Grounding and Bonding for Signs and Neon Installations

IAEI has had various requests recently to provide some basic information about the grounding of electric signs and neon lighting installations and to include the bonding requirements. To that end, this article will provide a brief tour through the electrical sign circuit and focus primarily on what is required for adequate grounding of this equipment and how grounding and bonding function together to provide safety for these types of equipment and installations.
NOVEMBER-DECEMBER 2004

The Wind of Change Hits the NEC

The first change that will be apparent is the relocation of Article 80, covering administration and enforcement requirements, to Annex G. The information has not been revised, is still informational in nature as it was in the 2002 NEC, and can be adopted as requirements by jurisdictions that so choose.
SEPTEMBER-OCTOBER 2004

Grounding Rules for Separately Derived Systems Reorganized and Revised

Section 250.30(A) has been reorganized and restructured to provide a more logical layout and improve clarity for users as a result of the work of a task group to achieve those primary objectives. Table 1 cross-references and outlines the new arrangement of this section and provides a comparison between how this section was organized in the 2002 NEC and how it is structured for the 2005 NEC. Various technical changes were also accepted during this cycle and were incorporated into the rewrite in the comment stage of the 2005 NEC development process [ROP 5-78, ROC 5-52].
JULY-AUGUST 2004

Static Protection through Bonding and Grounding

In many electrical installations today, some protection needs extend beyond the installation requirements of the Code. Static electricity and the buildup of static charges are major concerns in many installations such as data processing centers, semiconductor facilities, and many hazardous (classified) locations. In the information technology (IT) world, minimizing static electricity and circulating currents is a concern for protection of sensitive electronic equipment and events leading to data losses. In hazardous (classified) locations, on the other hand, electrical wiring, including the grounding and bonding circuits, is extremely important for safety of persons and property.
MAY-JUNE 2004

Grounding and Bonding Methods for Outbuildings

Most properties today, whether residential, commercial, or industrial, include at least one building or structure on that property. Often there are multiple buildings on a single property. Some include buildings that are each supplied by its own utility service and others have an electrical service at one point and deliver electrical power to the other buildings or structures by feeder(s) or by branch circuit(s). This article takes a closer look at the grounding and bonding requirements and methods for separate buildings or structures supplied from other than a service.
JANUARY-FEBRUARY 2004

Neon Secondary Circuits Over 1000

Neon lighting requires ignition of gas in processed tubing with higher voltages. Voltages in the required ranges are developed by transformation from a primary (low voltage) circuit input to a secondary (high voltage) output. The voltages are produced by appropriate neon transformers or power supplies. The supply chosen is directly related to three key factors, which include the size of tubing used, the type of gas contained within the processed tubing, and finally the length of tubing. The amount of tubing also has an impact on the number of transformers required for the installation. Placement of the transformer(s) or power supply can also determine the length of secondary (high voltage) circuit that must be installed from the supply to the neon tubing. This article picks up where we left off in the last issue and focuses on the general requirements for neon secondary circuit conductor installations from the high voltage hub or connection at transformer or supply to the first electrode in the tubing installation.
NOVEMBER-DECEMBER 2003

Proposed Code Changes for the 2005 NEC, Part 2

This article is intended to provide a preview of some of the more significant proposed changes to the 2005 NEC. This is a continuation of Part I provided in the July/August issue. It is important to understand that this summary is not intended to indicate that the Code is going to be revised as provided in this article, only that these are initial proposals that were acted on by the code-making panels in the proposal stage of the overall process. Part I reviewed various proposals from Articles 80 through 230. This collection of significant proposed changes provides a preview of proposed changes starting in Article 240 and visiting other revisions proposed to various other articles through to Chapter 8.
SEPTEMBER-OCTOBER 2003

Installing and Inspecting Neon Transformers

Neon signs and field-installed skeleton tubing installations require a transformer or power supply to step up the voltage to a high level that will cause ignition of connected neon tubing. This transformer can be considered the "heart beat” of the neon sign or outline lighting system. Recent articles in the IAEI News have been written to provide information relative to neon signs and neon installations. This article will visit some of the general requirements one must be aware of to properly install or inspect a neon transformer or power supply. Keep in mind that installation conditions can vary from site to site. There are some important factors and concerns involved with this type of installation that require close attention. High voltages require increased focus on insulation, spacing, and types of wiring methods and products used. Specified minimum clearances for high voltage conductors must be maintained.
SEPTEMBER-OCTOBER 2003

Neon Midpoint Secondary Return Circuits

Electrical circuit wiring requires building a proper path in which the electrical current can flow. Some fundamentals of electrical circuits are common to all circuits, including high voltage neon secondary circuits. One basic fundamental is that for current to flow, there must be a source (voltage) and a circuit that is complete and connected to the source. It should be understood that current will always try to return to its source. Basically, what goes out must return to the source (transformer or power supply). If the circuit (GTO secondary conductors) is not complete, and both supply and return circuit paths are not connected, the circuit will not work.
JULY-AUGUST 2003

Proposed Code Changes for the 2005 NEC

It is that time of the Code cycle again. Over 3,580 proposed changes were submitted to the National Fire Protection Association (NFPA) to amend the 2002 National Electrical Code (NEC). The 2005 NFPA-70 committees have been reduced from twenty code-making panels (CMP) to nineteen as a result of shifts in responsibilities in an effort to more evenly distribute the workloads among the panels. Many of the code-making panel responsibilities have not changed.
JULY-AUGUST 2003

Electric Sign Inspections: Listed Signs and Listed Section Signs

The National Electrical Code (NEC) is a minimum electrical safety standard; its primary purpose is directed at protection of persons and property from electrical hazards. Hazards of electrical shock, electrocution, and fires are some of the more serious consequences of noncompliance with minimum rules for safety. The NEC is the most widely adopted code in the world and many jurisdictions adopt it in its entirety without exception or local amendments or supplements. This article focuses on electrical signs and neon installations, what is included under the scope of Article 600, and some of the basics relative to the electrical inspection process.
MAY-JUNE 2003

Electrical Inspector Workplace Safety

It seems that many people do not take electricity and the associated hazards seriously enough. As the use of this great power has expanded into everyone’s daily life, electrical safety in the home and workplace is expected and taken for granted. People have come to expect electricity to work without interruption and have taken comfort in the technology and protective devices that make our life easier and safe.
MAY-JUNE 2003

Electrical Installation Requirements for Dwelling Units

Since 1897 the National Electrical Code (NEC), the world’s most widely used and adopted code for the built environment, has been the source for electrical installation requirements in all types of occupancies and applications, including dwelling units. The NEC was originally developed as a result of united efforts of various insurance, architectural and allied interests, and in 1911 the NFPA assumed stewardship of the NEC.
MARCH-APRIL 2003

Disconnecting Means for Motor and Air-conditioning Equipment

The purpose of electrical codes is practical safe guarding of persons and property from the hazards associated with electricity. Numerous prescriptive requirements address safety from the minimum standpoint. Codes and standards are the minimum rules for electrical safety, so one can easily surmise that for electrical safety one must do at least what is required by the codes.
JANUARY-FEBRUARY 2003

Isolated Power Systems

Generally, electrical systems used in power distribution systems for premises wiring are required to be grounded. The NEC includes rules that often make this determination. Some electrical systems are required to be grounded, while other systems are permitted to operate ungrounded (see 250.20 and 250.21). Then there are those systems that are not permitted to be grounded (see 250.22). One such ungrounded electrical system is the isolated power system utilized in health care facilities. This article focuses on some key installation requirements for these systems, and also takes a look at inspections of these ungrounded electrical systems.
NOVEMBER-DECEMBER 2002

Supplementary Grounding Electrodes

Electrical systems and non-current-carrying metal parts of equipment in an electrical installation generally are required to be grounded; however, alternatives are given within the NEC that relax the grounding rules for equipment. These alternatives include isolation, insulation, or guarding as methods of providing equal and effective safety measures without grounding the metal parts or equipment. It is important to meet all of the provisions of the Code when utilizing any of these alternatives.
SEPTEMBER-OCTOBER 2002

Inspections of Electrical Services

When a building or structure is supplied with electrical power, the equipment and conductors at the point of delivery to the premises are defined by the National Electrical Code as the service. This definition reads: "Service. The conductors and equipment for delivering electric energy from the serving utility to the wiring system of the premises served.”
JULY-AUGUST 2002

Training for Safety and the Future

May is Electrical Safety Month. During this time, many industry professionals and organizations try to focus on the safety aspect of the industry. From enhanced electrical safety writings to seminar offerings, it seems as though students of the Code at all levels contribute in some form or fashion. Electrical safety is no accident. Safe electrical installations have an absolute dependence on safety training. This article emphasizes the importance of electrical training and the critical role of those who train electrical workers and inspectors.
MAY-JUNE 2002

Grounding Separately Derived Systems

Grounding separately derived systems is required where the system meets the characteristics of 250.20. This section gives the conditions under which electrical systems are required to be grounded. A system that is grounded has one conductor of the system intentionally grounded. Whether the system is required to be grounded or is grounded by choice, it must follow all the requirements for grounding separately derived systems as covered in 250.30.
MARCH-APRIL 2002

Installations and Inspections of Corner-grounded Systems

Electrical systems are grounded to limit the voltage imposed by lightning, line surges, or unintentional contact with higher voltage lines and to stabilize the voltage to earth during normal operation. Electrical systems can be grounded in several ways. There are induction grounded systems, resistance grounded systems, and high impedance grounded systems among others. The most common grounded system is the solidly grounded system, where there is no intentional grounding impedance in the earthing or grounding circuit. Common solidly grounded systems are 3-phase, 4-wire, high-leg delta systems; 3-phase, 4-wire, wye-connected systems; and 1-phase 3-wire grounded systems.
JANUARY-FEBRUARY 2002

Inspectors Thirst for Knowledge

Building a career in the electrical trade requires personal investment in continuing education. Knowledge of the National Electrical Code is the common thread that connects entry-level apprentices to the seasoned journey-level or veteran master electricians with many years of experience in the field. As one starts out in the electrical field, his or her exposure to and use of the NEC is minimal, but before long, serious electricians realize the importance of Code knowledge in their day-to-day work. Training in electrical theory together with an understanding of how and why things work allows them to properly apply the Code rules to electrical installations.
NOVEMBER-DECEMBER 2001

Overcurrent Protection for Conductors

Requirements for overcurrent protection for conductors are found in Article 240, Overcurrent Protection, which is found in chapter two, Wiring and Protection, of the NEC. Electrical conductors are required to be protected against overcurrent in accordance with their ampacity ratings that are specified in Section 310-15. Chapter three covers wiring methods, and the conductors installed in conjunction with those wiring methods must follow the applicable requirements of Article 310, Conductors for General Wiring.
SEPTEMBER-OCTOBER 2001

Concrete-encased Electrodes and the Grounding Electrode System

Most buildings or structures employ a structural design that includes a concrete footing or foundation, which connects the structure to the earth. For the building to be structurally sound and stable, a substantial foundation must be established to bring the structure out of the ground. Footings and foundations are typically constructed using concrete and reinforcing rods or bars for structural strength.
JULY-AUGUST 2001

Emergency Electrical Systems Installations and Inspections

The installation and inspection of an emergency electrical system are critical elements regarding the protection of persons set forth in Section 90-1 of the National Electrical Code. Requirements for the emergency electrical circuits and emergency system are more restrictive than the rules for normal circuits and systems in chapters 1 through 4 of the Code. It is important that those involved with the design, installation and inspection of the emergency system know and understand their responsibility in meeting the minimum requirements in the applicable codes. This article will take a closer look at a few of the key concepts and requirements that must be considered and verified regarding emergency electrical wiring and systems.
MAY-JUNE 2001

Performance Testing Requirements for Ground Fault Protection Equipment

Two types of ground-fault protection are required by the Code: ground-fault circuit interrupter protection (GFCI) and ground-fault protection of equipment (GFPE). A ground-fault circuit interrupter is intended to protect persons against shock and electrocution. As implied by its name, ground-fault protection of equipment protects equipment from damaging line-to-ground faults. More detailed definitions of these devices are found in Article 100.
MARCH-APRIL 2001

Installations and Inspections of Information Technology Equipment

In the 1996 National Electrical Code the title of Article 645 was changed from Computer/Data Processing Equipment to Information Technology Equipment (ITE). This change reflects the fact that computer rooms are more than just for housing computers. In many cases they are the heartbeat of organizations.
JANUARY-FEBRUARY 2001

Path of Least Resistance

Anyone who has been involved in the electrical field for any length of time has heard the phrase, "path of least resistance,” on many occasions. From the first-year apprentice starting out in the electrical trade to the seasoned veteran of the industry with many years of experience and accomplishments, the phrase is used to describe what path electrical current will take. The phrase is stated with pride "Electricity takes the path of least resistance,” or "Current takes the path of least resistance,” and usually not much thought is given to what is really meant by that statement. This article will review some basic principles of this fundamental element and discuss how this current flow relates to electrical safety.
NOVEMBER-DECEMBER 2000

Overcurrent Protection for Air-Conditioning and Refrigeration Equipment

Overcurrent protection for electrical equipment can be accomplished by several different methods. The general rules for overcurrent protection of conductors and equipment are found in Article 240 of the National Electric Code. Section 240-2 indicates Article 440 shall be used for protection of air-conditioning and refrigerating equipment.
JULY-AUGUST 2000

Installations and Inspections of Motors and Motor Circuit Protection

Overcurrent protection for motors and motor circuits is a little different than the rules for conductors as specified in Article 240, because motor loads have different characteristics than general lighting and other loads. Motor circuits draw a large amount of current at initial start-up, usually around six times the normal full-load current (FLA) of the motor. This large amount of current drawn at start-up is usually referred as the "inrush current,” although the Code term is "locked rotor current” (LRA).
MAY-JUNE 2000

Installations and Inspections of Motors and Motor Circuit Protection

The electrical inspector and electrician are no different from any other craftsman. As they accumulate more experience and expertise in their field they begin to achieve a level of comfort with the tasks they perform on a regular and routine basis. Unfortunately, as the comfort level increases, the potential for complacency can begin to set in. In the electrical industry, there is no room for complacency.
MAY-JUNE 2000

Back to Basics: Grounding and Bonding as it Relates to Signs and Neon Installations

Some features of electrical circuits and electrical systems are so fundamental they have appeared in some form in every edition of the National Electrical Code. These include insulation for wire type conductors, conductor (wire) sizing, and overcurrent protection for circuits (fuses or circuit breakers). Another long-time electrical safety requirement is grounding of electrical systems and equipment for safety.
JANUARY-FEBRUARY 2000

Ground-fault Protection of Equipment and Ground-fault Circuit Interrupters

Injuries, death, property loss, and downtime for facilities are all situations that can result when the required ground-fault protection for equipment or ground-fault circuit interrupters are not installed as required by the NEC.
SEPTEMBER-OCTOBER 1999

Grounding & Power Quality: The Best of Both Worlds

Many businesses are concerned these days with the cost of electrical energy supplying power to their facility, but an increasing number of them are getting real concerned about the quality of the power being utilized at their facility. So what is the problem with the quality of power being delivered to a facility? Many businesses are extremely nervous about loss of data or data errors that can result from this "dirty power” or "electrical noise” on the system. Does this sound familiar? So what do they do?
MAY-JUNE 1999