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May-June 2012
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May-June 2012 CoverMay/June 2012

TABLE OF CONTENTS

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Features

What is Ladder Logic? Why is it important for troubleshooting motor operations?

by Stephen J. Vidal

Electric machines are very useful and efficient devices which operate through a variety of control circuits. These control circuits are made up ofinputdevices that sense a condition or situation andoutputdevices that make adjustments to change the situation. The symbolic language for this process is calledladder logic. Many of the diagrams used resemble the steps of a ladder; hence, the addition of the word "ladder” into the title. Read more

Perspectives on PV

Microinverters and AC PV Modules Are Different Beasts

by John Wiles

Microinverters and AC PV modules are becoming very common in residential and small commercial PV systems. They have even been used in PV systems rated at 60 kW and above. They have some common features. For example, microinverters and AC PV modules have similar ac output characteristics, connections and code requirements. Read more

GFCI and AFCI Basics

by Alan Manche

GFCI and AFCI protection have both become fundamental safety devices in electrical systems. Understanding the basics of ground-fault protection for people, and arc-fault protection for 15- and 20-amp branch circuits in dwelling units can ensure that your installations are code-compliant and help you in troubleshooting a circuit. As of the time this article was written (late January 2012), the NFPA code-making panels have met to consider proposals for the 2014 NEC. Read more


NEC Requirements for Short-Circuit Current Ratings

by Daniel R. Neeser

Overcurrent protective device interrupting rating (IR) and equipment short-circuit current rating (SCCR) are key considerations for the safety of commercial and industrial electrical systems. If inadequate overcurrent protective device IR or equipment SCCR is present, a serious potential safety hazard exists. Read more

NEC-2014, Call for Comments

by Don Offerdahl

The NEC Code-Making Panels met to act on NEC proposals in January 2012. The results can be found at:http://www.nfpa.org/AboutTheCodes/AboutTheCodes.asp?docnum=70&tab=nextedition. This is the time to bring comments to the electrical industry by using your IAEI membership. Under the NFPA rules, anyone can submit a comment under his or her own name. IAEI encourages that and does not restrict, in any way, anyone wishing to make such submissions. Read more


Wiring Methods

by Randy Hunter

Section 4 of the Canadian Electrical Code covering conductors has seen ten revised subrules, eleven new subrules and one new rule for the 2012 CE Code. The most significant change to Section 4 is the addition of new Rule 4-006. Similar to Article 110.14 of the National Electrical Code, Rule 4-006 limits the maximum allowable ampacity of a conductor to be based on the lesser of the temperature rating of the conductor or the maximum termination temperature marked on equipment. Read more

Article 220 — Branch-Circuit, Feeder, and Service Calculations

by Randy Hunter

Article 220 is a cornerstone of theNational Electrical Code which gives us the information we need to properly size the circuits which will provide power to each part of our electrical system. Fundamentally, it is the section of the code which requires the most detail, and during certification testing it is usually one of the most dreaded. Good organization and some basic math skills are required to properly perform the calculations found in Article 220. Read more


General Use Snap Switches

by Keith Lofland

What has a couple of poles and says "NO” when turned upside down?Answer:A single-pole switch! Weren’t we all taught asapprentice electricians and helpers that if you install a single-pole switch upside down, rather than say "ON” it will say "NO” to you! We perhaps take switches for granted. Receptacle outlets are the "face” of electrical devices, and luminaires are often grand and elegant in design and attract lots of attention. Read more

Jumping to Conclusions

by Steve Foran

Can you think of a time when you thought you were being taken advantage of… and later realized that you were wrong? A friend related a recent experience to me. He described a confrontation with a middle-aged man who scours the streets in his neighbourhood looking through garbage for beverage containers that he returns for cash. Read more


Intersystem Bonding, 250.94

by Jonathan Cadd

Cycle after cycle, men and women tirelessly volunteer their time and expertise in the electrical industry to meet together to forge yet another version of the NEC — this year the 2014. As I sat beside and observed these hardworking volunteers, I was reminded of an earlier group who were similarly engaged. Read more

IAEI Education Committee is Vital to Change and Solutions

by IAEI

Education is vital in our industry, whether it is needed because of improvements in technology and installation methods or because of changes in codes and standards. The only constant we have is that our electrical world is constantly changing. Read more



Departments

Editorial

Added Values: How do we monetize them?

by David Clements

Despite the downturn in the economy which has affected us all, IAEI has been looking for ways to provide additional services to help its members and the electrical industry. One of the most exciting new services is IAEI Career Center which was recently launched in March. This interactive job board focuses on electrical industry companies and offers IAEI members — and the electrical industry at large — an easy-to-use and highly targeted resource for online employment connections. Read more

Canadian Code

The New 2012 Canadian Electrical Code

by Leslie Stoch

I excitedly cracked open my shiny, new Canadian Electrical Code to see what the future might bring. I found it full of surprises, most of them good, some others not so much. Here are a few thoughts. Read more

Canadian Perspectives

Location of Electrical Distribution Equipment in a Building — Are we consistent on this subject?

by Ark Tsisserev

The subject of the required location for such electrical equipment as switchgear, panelboards, MCCs, switches, circuit breakers, capacitors and transformers and of the required clearances (working space) about these types of equipment is not new. Read more

Safety in Our States

Readily Accessible

by Thomas A. Domitrovich

It’s eight o’clock at night and you find yourself standing in front of energized equipment because you were called about an unplanned inspection and they needed it done right away. You realize you are going to be in and around energized equipment. It’s late. You didn’t plan on being here, and what is being asked of you seems to be quite simple. Read more

UL Question Corner

DC AFCIs for Photovoltaic Systems Now Certified

by Underwriters Laboratories

2011 NEC 690.11 requires DC arc-fault circuit interrupter protection in DC photovoltaic (PV) circuits. Are there any certified (listed) DC arc-fault circuit interrupters (AFCIs) for use in PV circuits? What requirements are used for certification? Read more

UL Question Corner

Does UL certify (list) Photovoltaic (PV) module tracker devices?

by Underwriters Laboratories

Does UL certify (list) Photovoltaic (PV) module tracker devices? What about grounding lugs for PV modules? Where can I find this information? Read more

UL Question Corner

Is there anything new in wind turbine certifications?

by Underwriters Laboratories

Yes, recently UL has created two new wind turbine certification product categories, Wind Turbine Drive-train Systems and Equipment (ZGDT) and Wind Turbine Tower Assemblies (ZGTA) both of these categories can be found in a list of Wind Power Systems product categories located on page 34 in the 2012 UL White Book. Read more

Focus on the Code

Do washing machines require GFCI protection?

by Mark Hilbert

An inspector told me the other day that a washing machine in a dwelling unit required GFCI protection. I’ve looked and I can’t find that requirement in the 2011 NEC. Can you help me with this requirement? Read more

Focus on the Code

Are there any other such receptacle replacement requirements?

by Keith Lofland

I know the Code requires GFCI protection for replacement receptacles in existing dwellings where receptacles are replaced in areas that would require GFCI protection under today’s Code. Are there any other such replacement requirements for other things such as AFCI protection elsewhere in the Code? Read more



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