Print Page   |   Contact Us   |   Sign In   |   Join
IAEI Magazine
Blog Home All Blogs
IAEI News provides educational forums, updates on electrical codes and reports of innovative research to facilitate the development and enforcement of practices designed to drive efficiency and compliance with the highest standards of product development and safety—for the public as well as for electrical personnel. The magazine reaches authorities with power of product specification, approval and acceptance. Published six times a year by the International Association of Electrical Inspectors.

Issue Archive | Advertise | Media Kit | Submit Article

 

Search all posts for:   

 

Top tags: Featured  UL Question Corner  Canadian Code  Editorial  Other Code  Canadian Perspective  May-June 2012  November-December 2011  Safety in Our States  January-February 2012  March-April 2012  January-February 2008  September-October 2012  July-August 2011  May-June 2005  May-June 2010  May-June 2011  November-December 2000  November-December 2010  January-February 2009  July-August 2006  March-April 2005  March-April 2011  May-June 2003  November-December 2008  November-December 2012  January-February 2010  July-August 2009  November-December 2009  September-October 2005 

UL Certifies First Modular Data Center

Posted By Underwriters Laboratories, Tuesday, January 01, 2013
Updated: Thursday, December 13, 2012

Question

With the advent of cloud computing, there seems to be a lot of modular data centers popping up. Does UL certify (List) modular or containerized data centers that are typically housed in an enclosure like a shipping container and are filled with computer servers?

Answer

Recently, UL certified (Listed) its first modular data center. UL certifies (Lists) these products under the product category Modular Data Centers (PQVA) located online at www.ul.com/database (enter PQVA at the category code search field). This category covers modular data centers (MDCs) that are self-contained assemblies of information technology equipment (ITE) installed within prefabricated enclosures. MDCs may utilize integral support equipment such as power distribution units, HVAC equipment, standby power, illumination and others required for operating the ITE. In some cases, this support equipment may be housed in its own separate enclosure and certified as part of the MDC system. Modular data centers, as covered under this category, are sometimes referred to as "containerized data centers.”

MDCs are composed of an enclosure, all equipment and components located within an enclosure, and all components mounted to the enclosure walls. An MDC may permit temporary entry of authorized personnel for service, maintenance and upgrading of the ITE and associated support equipment. MDCs are not intended to be used as an occupied space (as in an office) for personnel.

MDCs are investigated as complete equipment including all subassemblies, power distribution, cabling, cooling system components, lighting and the like, installed within an enclosure. Consideration has also been given to emergency egress and working space around equipment. MDCs are not investigated as an ITE room as described in ANSI/NFPA 75, Protection of Electronic Computer/Data Processing Equipment, and Article 645 of the National Electrical Code (NEC). The PQVA category does not cover preconfigured ITE rooms that are shipped as individual pieces of equipment or subassemblies and later assembled on site.

Information concerning field-wiring connections, mounting location, site preparation, installation clearances, etc., is marked on the MDC and/or is provided in detailed installation instructions accompanying each MDC.

Working space within an MDC is evaluated as part of the equipment investigation. Access and working space around electrical equipment accessible from the outside of the MDC (such as an outward-facing panelboard or field-wiring compartment) must comply with the applicable requirements in NEC 110.26 after installation is complete.

MDCs often require special installation, such as a separate transformer, special grounding methods, motor-generator equipment, external chillers, etc. Such features, if required, are covered in a manufacturer’s installation instructions.

MDC systems consisting of the main MDC enclosure housing the ITE and one or more accessory enclosures for power, cooling, etc., are investigated as a system and are identified as such in the individual certifications. The relationship and interconnections between the parts of the system are clearly identified in a manufacturer’s installation instructions. Interconnecting power, signaling, and communications wire and cable not investigated as part of an MDC system is intended to be installed in accordance with the applicable provisions of the NEC. The accessory equipment is marked with a reference to, and the identification of, the equipment with which it is intended to be used.

The proper method of electrical installation (number of branch circuits, control wiring connections, etc.) is shown on the wiring diagram and/or marking attached to the equipment.

The basic requirements used to investigate products in this category are contained in UL Subject 2755, "Outline of Investigation for Modular Data Centers.”

New Article 646, titled Modular Data Centers has been proposed for the 2014 NEC. It was accepted in principle in the NEC Report on Proposals (ROP) and included in the proposed draft of the 2014 NEC.


Question

Does UL provide certification for qualified electricians interested in installing photovoltaic (PV) systems?

Answer

Yes. Recently, UL and the International Brotherhood of Electrical Workers (IBEW), announced an agreement to begin offering UL’s photovoltaic (PV) installer certification to IBEW members and the National Electrical Contractors Association (NECA). The collaboration will provide members access to a nationally recognized UL credential, enable them to broaden their skills in an increasingly competitive labor market and improve market access to licensed, qualified electricians for safer PV installations.

UL’s PV installer certification and training program, established in 2010, was designed to meet and exceed existing industry requirements through a working cooperation with stakeholders, nongovernmental organizations (NGOs) and professional associations. By making the certification exam available to more than 675,000 IBEW members and 119 local NECA chapters, UL builds on that commitment and helps improve the safety and performance of PV systems through a more qualified workforce. Unlike other programs, UL only certifies qualified professionals, including licensed electricians or final year apprentices in the National Joint Apprenticeship and Training Committee (NJATC) PV training program.

To earn UL personnel certification, electricians completing a hands-on, classroom-based PV training program with either UL Knowledge Services or NJATC must register and sit for a formal exam assessing their knowledge. Successful exam completion earns final year apprentices status as UL certified PV installers in training, while journeymen are named UL certified PV installers.

For more information or to register for the exam, visit www.njatc.org/cert/pv/about.aspx.

For more information on PV installer training by UL Knowledge Services visit http://lms.ulknowledgeservices.com/certification 


Read more by UL

Tags:  January-February 2013  UL Question Corner 

Share |
PermalinkComments (0)
 

Gratitude — The Path to Excellence

Posted By Steve Foran, Tuesday, January 01, 2013
Updated: Thursday, December 13, 2012

After one of my gratitude workshops, a business owner remarked, "If I let my staff know that I am grateful for their performance when they fall short of a goal, I am basically giving them permission to underperform. And I just cannot allow that because we will never grow or achieve our stretch goals.”  

I did not offer up a good response and his comments sent me searching for a better answer.

Here goes…

Genuine gratitude is not about accepting mediocrity. Fundamentally, gratitude is the feeling you experience when you attribute the positive aspects of your life to others. However, the state of gratitude is not limited to when things are good — but at the same time it is critical to understand that gratitude is not a Pollyanna masquerade for when things are bad simply to make them appear good.

Although gratitude is a foundation for happiness, it is not pixie dust that makes everything pleasant, at least not immediately. Genuine gratitude acknowledges the truth and sees reality for what it truly is — the good and the bad — it just allows you to do so from an appreciative perspective. This can be difficult and at times, it is near impossible.

Being appreciative about less desirable situations is tough because it is easy to focus on the negative aspects of the situation or it can be just as easy to gloss over the challenges and whitewash them with unbridled optimism. Or, as in the case of the bottom-line focused workshop participant, it can be perceived as accepting a life of mediocrity.

My response to the comments at that workshop was weak. In fact, it was somewhat embarrassing. As I drove away I wished I had said something else.

Then the analogy appeared. As a young engineer I was responsible for implementing a quality program in a large organization. Like all quality programs, we strived for continuous improvement. When mistakes were made, we jumped on them to learn — not just to fix the problem but, more importantly, to prevent the mistake from ever happening again. The investigations sought to inform not to blame.

After the investigation, we would learn something about what caused the error and we always found that some parts of our process were working just fine. Using this approach, we learned from our shortcomings and celebrated what we did well. This was our path to excellence and it was anything but mediocrity. In hindsight, we could have called them gratitude investigations.

Whether it is in your personal or professional life, gratitude actually transforms "accepting mediocrity” into "chasing excellence.” The systematic practice of gratitude parallels how one would investigate a non-conformance in a quality program. Both ideas are rooted in accepting and appreciating reality, but not for the sake of being stuck in that reality. Instead, they both know that future success is built upon the success of the current reality and what can be learned about the current reality. If you can obtain this mindset about your current reality, even if it is horrible, you’ll realize that your current reality is actually a gift.

His comment and my awkward response was a gift of enormous magnitude but it did not feel like a gift at the time. Yet, I am ever grateful he spoke up.


Read more by Steve Foran

Tags:  Featured  January-February 2013 

Share |
PermalinkComments (0)
 

Operating Portable Generators

Posted By Underwriters Laboratories, Tuesday, January 01, 2013
Updated: Thursday, December 13, 2012

When a hurricane downs power lines, electricity is often one of the initial services to fail. In response, many people use portable generators to weather the inconvenience until power is restored.

Carbon Monoxide Hazards

While a portable generator can solve some of the stress of managing a storm’s aftermath, consumers need to operate them with caution. Portable generators are powered by internal combustion engines. As the fuel burns to power the generator, it emits carbon monoxide (CO) into the air. If the generator isn’t properly positioned, consumers risk CO poisoning. "The danger of carbon monoxide poisoning from portable generators is a true threat during storm season,” says John Drengenberg, UL’s consumer affairs director. "But if you take the proper precautions, you can use a generator safely.”

UL, a global safety organization, recommends the following safety tips to protect against carbon monoxide poisoning:

Place the portable generator as far away from the home as possible –

• NEVER use a generator inside homes, garages, crawl spaces, or other partly enclosed areas. Deadly levels of carbon monoxide can build up in these areas. Using a fan or opening windows and doors does NOT supply enough fresh air.

• ONLY use a generator outside and far away from windows, doors, and vents. These openings can pull in generator exhaust.

Use a carbon monoxide alarm – Even when you use a generator correctly, CO may leak into the home. ALWAYS use a battery-powered or battery-backup CO alarm in the home.

• Follow instructions – Follow the instructions that are provided with your generator. Being mindful of these guidelines helps ensure that the CO produced by the generato will not find its way into the home, where it can potentially endanger occupants.


Electrical Hazards

NEVER power the house by connecting a generator to a receptacle outlet – The practice, known as "backfeeding,” is extremely dangerous and presents an electrocution risk. Generators used to power a building during an outage must be connected through transfer equipment that isolates the generator supply from the utility supply.

Use proper electrical connections – Use UL-listed outdoor extension cords when connecting the generator to run power back to the house. Also, note the maximum wattage a generator produces, and never exceed that amount with the appliances you plug in. Appliances should have their wattage listed on the products.

Ground fault circuit interrupters (GFCIs) – These can help prevent electrocution. The majority of portable generators do not include GFCI protection. Use of a portable GFCI is recommended. It requires no special knowledge or equipment to install. 

One type contains the GFCI circuitry in a self-contained enclosure with plug blades in the back and receptacle slots in the front. It can then be plugged into a receptacle, and the electrical products are plugged into the GFCI. Another type of portable GFCI is an extension cord combined with a GFCI. It adds flexibility in using receptacles that are not protected by GFCIs. Portable GFCIs should be used only on a temporary basis and should be tested prior to every use.

One type contains the GFCI circuitry in a self-contained enclosure with plug blades in the back and receptacle slots in the front. It can then be plugged into a receptacle, and the electrical products are plugged into the GFCI. Another type of portable GFCI is an extension cord combined with a GFCI. It adds flexibility in using receptacles that are not protected by GFCIs. Portable GFCIs should be used only on a temporary basis and should be tested prior to every use.

Portable generators typically are not weatherproof – They can pose the risk of electrocution and shock when used in wet conditions. Use them outdoors, but keep them protected from direct exposure to rain and water. Generators should be operated on a dry surface where water cannot reach them.

Generators vibrate in normal use – During and after use of the generator, inspect it as well as extension cords and power supply cords connected to it for damage resulting from vibration. Have damaged items repaired or replaced as necessary. Do not use plugs or cords that show signs of damage, such as broken or cracked insulation or damaged blades.


Fire Hazards

Limit gasoline storage and look for the UL Mark on gasoline containers – Gasoline expands when heated, producing fumes that can be ignited by the smallest spark. The more gas on hand, the more fumes in the air and the greater the risk of a fire starting from even a light switch or static electricity.

Fuel and vapors are extremely flammable – Before refueling the generator, shut the engine off and let it cool down, as fuel spilled on hot parts can ignite.

For more information, visit ul.com/hurricanesandy


© 2012 UL LLC All rights reserved. May not be copied or distributed without permission.

Read more by UL

Tags:  Featured  January-February 2013 

Share |
PermalinkComments (0)
 

Another Look at Appendix B

Posted By Leslie Stoch, Tuesday, January 01, 2013
Updated: Thursday, December 13, 2012

In an earlier article, I suggested checking for an Appendix B interpretation when applying any of the Canadian Electrical Code rules for the first time.  Appendix B is there to help us better understand the intent of the CEC rules and to provide important supporting information. Here are a few more examples.

Rules 4-004 (1) (d) and 4-004(2) (d) provide allowable ampacities for underground wiring. Conductor configuration Diagrams B4-1 to B4-4 for underground conductor installations are located in Appendix B and the allowable ampacity Tables D8A to D15B associated with these   diagrams for copper and aluminum underground conductors in Appendix D. The ampacity tables are based on 90 C rated conductors.

However as you know, the new Rule 4-006 requires that when equipment is marked with maximum connection temperatures, the conductor ampacities must be based on the applicable columns in Tables 1 to 4. To convert the 90° C conductor ampacities, Appendix B  explains that underground ampacities for conductor temperatures of 75° C to 60° C respectively may be obtained by multiplying the 90° C temperature ampacities by the derating factor 0.886 (for 75° C) or 0.756 (for 60° C). These conversion factors help us meet the requirements of Rule 4-006.

Rule 2-320 requires that adequate ventilation be provided to prevent overheating of heat-producing electrical equipment. Appendix B helps us by specifying that approximately 3.5 to 4.3 cubic metres of air per minute is normally provided for each kilowatt of loss for ventilating 40° C rise equipment.

Rule 10-500 defines effective grounding as a ground-fault path of sufficiently low impedance so as to facilitate operation of overcurrent devices (fuses and circuit-breakers). Appendix B explains that an effective ground-fault path will have impedance sufficiently low enough to permit at least five times rated current to flow during a ground fault. This definition explains various rules that call for effective grounding.

Rule 10-814(1) specifies that bonding conductor sizes must not be smaller that specified in Table 16. Appendix B makes two important exceptions to the rule:  

  1. When correctly sized raceways (conduit or tubing) and metallic cable sheaths are permitted for use as bonding conductors, they are considered to be adequate for the purpose.
  2. Bonding conductors in cable assemblies are sized in accordance with the applicable Part II standards – although bonding conductor sizes may differ from Table 16, they are considered adequate for the purpose.

Rules 18-050 and 18-066 provide requirements for selection of equipment when employing the Zone system of classifying locations for flammable and explosive gases and vapours. To assist us in identifying hazardous location equipment, Appendix B supports the rules with detailed specifications for the hazardous gas groups.

Rule 32-202 specifies permissible wiring methods for fire pumps, (metal raceways, cables with metal armour or sheaths and non-metallic conduit and tubing in minimum 50 mm concrete). Appendix B takes the requirements for fire pump wiring a step further with this recommendation "Consideration should be given to the location, routing and design of wiring to minimize hazards that might cause failure due to explosions, floods, fires, icing vandalism and other adverse conditions that might impair the function of a fire pump”. This extra step is taken to help ensure that power will be available when fire pumps are called upon to perform in an emergency.

With the examples given in these two articles, I hope I have convinced you of the value that you can find in Appendix B.

As with previous articles, you should always check with the electrical inspection authority in each province or territory for a more precise interpretation of any of the above.


Read more by Leslie Stoch, P. Eng

Tags:  Canadian Code  January-February 2013 

Share |
PermalinkComments (0)
 

2013 Your New year Electrical Safety Checklist

Posted By Thomas A. Domitrovich, Tuesday, January 01, 2013
Updated: Friday, December 14, 2012

"Get your head in the game”

It’s a new year and a great time to get your head in the safety game. The New Year is a great trigger to prompt safety meetings and to create the dialog to understand your successes and failures and to chart the safety course for the New Year. Yes, the New Year can be a trigger for this type of activity as triggers for safety actions are not new as evidenced by the changing of the clocks initiating the replacing of batteries in smoke alarms. It is unfortunate that the New Year has become associated with lost causes; sort of like the resolution to lose those unwanted pounds found over the holidays. Then again, it could be that the New Year just hasn’t met electrical safety yet, so let’s make the introductions and change the previous association to one of success and saving lives.

The 6-Point New Year Safety Checklist

The focus of this effort is to get the organization engaged with electrical safety at the beginning of the year, sparking team energy that will start your year off in the right direction. Your organization is not just the CEO, the safety committee, management or just the employees. Your organization is everyone. Everyone has a role to play. The 6 points highlighted as part of this article are not meant to dig into details and implementation; that is left to your team as everyone has a role to play in these details. How you are or will address each of these items in your organization is the discussion that needs to happen with your team. Your direction/action will not be the same as others. Every organization and their circumstances will be unique. The implementation plan should be written down for years to come. This gets more and more important as the size of the organization increases, as there are more individuals to communicate with and to track.

 Photo 1. Smoke alarm check.

 Photo 1. Smoke alarm check.

I have placed the following points in a specific order as they build on each other. These are high-level thought-provoking drivers, not specific point-by-point items that address details. This list should prompt you and your team to dig deeper in one or more meetings. Because your team should already be doing the right things from a safety perspective, the following should be able to get the entire team moving rather quickly.

Annual Performance Review

This is your report card that shows how well your plan worked last year. Reviewing this data as a team should help identify concerns and issues that need to be addressed. Total hours worked, number of injuries, number of cases with days away from work and other recordable data points are just a few statistics that should be collected over time. Some organizations elect to record "near misses” as a way to identify areas where improvements can be made.

You will also need to get beyond the numbers to identify the areas of concern and to identify improvements that can be made. This is where the near miss data point and background around each event can come in handy. Many organizations may be faced with a record of no accidents, no time off, no deaths and more good results. Some organizations elect to record in the near miss category. Participation and accuracy are important and can be very helpful. That’s why everyone is important in the collection of this data.

Your safety performance data relies on everyone. If events are not reported or are reported incorrectly and inaccurately, your safety performance reports will not be accurate or complete. Then, too, if all employees are completing the forms and submitting corrective action reports correctly and accurately and upper management doesn’t act on the data, the safety machine breaks down. Safety performance reviews should drive action and your budgets must be able to handle the actions necessary. Your data should help you budget accordingly.

 Photo 2. A good place to start is right in your own toolbox. Checking your tools for those that need to be replaced or repaired can help ensure a safe New Year. Treat your tools with the respect they deserve and, by all means, use the right tool for the job.

 Photo 2. A good place to start is right in your own toolbox. Checking your tools for those that need to be replaced or repaired can help ensure a safe New Year. Treat your tools with the respect they deserve and, by all means, use the right tool for the job.

Some organizations look at safety as a profit center. The data collected helps drive this home because every event or non-event costs or saves the organization money. Reducing accidents, down time, loss of work time and other areas of incurred expenses because of accidents goes straight to the bottom line.

Equipment Check

The equipment check should range from the big trucks and lifts that you own and use, down to the screwdrivers and side cutters and everything in between (photo 2). Your teams should be looking for wear and tear and any maintenance that needs to be performed. When you find safety equipment that needs replaced, get it out of use and replaced as soon as possible.

The responsibilities don’t stop when the message goes out to everyone that they need to check their tools and equipment. It’s the responsibility of management to ensure the funding is in place to replace the failed or failing equipment. The equipment check activities can help to define your future budgets as some equipment can be designated for replacement in the coming years. This information is critical for your budgeting exercises.

Code / Regulation Update

Codes and regulations change every now and then and you need to stay on top of them. This applies to more than just the National Electrical Code (NEC) and other similar documents. This applies to OSHA and other regulations that may be mandated for your business as well. Ensure you are referencing the latest version of the documents used in your business operations.

Budgets may be impacted by new regulations as well. Unaddressed, these changes can quickly suck the finances from your safety plans. It’s important to not only know what current regulations and codes are in place, you need to know what is coming down the road so you can anticipate changes in future budgets.

Safety Plan Update

Review your safety plan every year with your team. The data recorded above may influence changes to your plan. Make the appropriate changes. You’ll worry about communicating and training on these changes as one of the other bullet points below. Your budget may change as well. Equipment checks, statistics reviews and, yes, new codes and regulations may influence changes in your safety plan. Take this annual opportunity to continue the improvement of this important document. Your entire team should have an opportunity to suggest changes to your safety plan. Those individuals who are implementing the plan and performing work on a daily basis are probably the best people in your group to help improve this document. They see what happens on a daily basis and if encouraged correctly, could add valuable information that will help improve the plan.

Training

By this step in the checklist you will have a lot of information that is important for your training program. You may have uncovered various areas of concern and quite possibly implemented improvements that will have to be communicated through your training programs. Ensure you include your performance data, equipment check information and any codes / regulations that your people should be familiar with. This information helps reinforce your level of commitment to the safety program at all levels in the organization.

Your discussions around training should go well beyond internal training; it needs to include your "qualified individuals” and the necessary training they need to keep them up-to-date on their specific training needs. This is a time to identify the IAEI meetings that are available and can be made available to meet your specific training needs. CEU credits will need to be obtained for those that hold licenses in your organization.

This, too, will need to be funded. Everyone has his or her role to play and the management’s responsibility is to ensure the time and the finances are available to ensure your people are adequately educated. There are many opportunities for external help in this area, all you need to do is identify the need to seek this help out, schedule it and ensure it is funded.

Communications

Everyone in your organization should be involved in your annual safety review and should be made aware of the progress you are making. All of the points above will need to be communicated throughout the entire year. Updates to the safety plan, your annual safety performance, equipment replacement plans and activities are all fodder for communication plans. A good communications plan shows the employees the level of commitment the organization has to safety. Sharing your statistics reminds everyone of the commitment and re-enforces your implemented safety procedures. Share with them information on the organization’s investment in safety; this shows you have skin in the game as well and are committed to safety.

The above list is meant to get your head in the game, to get you to start thinking about those critical safety aspects that need to occur on an annual basis, if not on a monthly basis. Safety should be an ongoing process. If the New Year is not your trigger, maybe it’s when you turn the clocks back or when your fiscal year ends. It could be a birthday, anniversary, or simply a date that everyone has in their calendar and is your declared day of safety. Whatever your trigger, make sure you get your head in the game and fight for safety.

As always, keep safety at the top of your list and ensure that you and those around you live to see another day.


Read more by Thomas Domitrovich

Tags:  January-February 2013  Safety in Our States 

Share |
PermalinkComments (0)
 

401(k) Loans: The Last Resort?

Posted By Jesse Abercrombie, Tuesday, January 01, 2013
Updated: Friday, December 14, 2012

As you’re well aware, we’re living in difficult economic times. Consequently, you may be forced to make some financial moves you wouldn’t normally undertake. One such move you might be considering is taking out a loan from your 401(k) plan — but is this a good idea?

Of course, if you really need the money, and you have no alternatives, you may need to consider a 401(k) loan. Some employers allow 401(k) loans only in cases of financial hardship, although the definition of "hardship” can be flexible. But many employers allow these loans for just about any purpose. To learn the borrowing requirements for your particular plan, you’ll need to contact your plan administrator.

Generally, you can borrow up to $50,000, or one-half of your vested plan benefits, whichever is less. You’ve got up to five years to repay your loan, although the repayment period can be longer if you use the funds to buy a primary residence. And you pay yourself back with interest.  However, even though it’s easy to access your 401(k) through a loan, there are some valid reasons for avoiding this move, if at all possible. Here are a few to consider:

You might reduce your retirement savings. A 401(k) is designed to be a retirement savings vehicle. Your earnings potentially grow on a tax-deferred basis, so your money can accumulate faster than if it were placed in an investment on which you paid taxes every year. But if you take out a 401(k) loan, you’re removing valuable resources from your account — and even though you’re paying yourself back, you can never regain the time when your money could have been growing.

You might reduce your contributions. Once you start making loan payments, you might feel enough of a financial pinch that you feel forced to reduce the amount you contribute to your 401(k).

You may create a taxable situation.  Failure to pay back loans according to the specified terms can create a taxable distribution and possibly subject the distribution to a 10% penalty.

You may have to repay the loan quickly. As long as you continue working for the same employer, your repayment terms likely will not change. But if you leave your employment, either voluntarily or not, you’ll probably have to repay the loan in full within 60 days — and if you don’t, the remaining balance will be taxable. Plus, if you’re under age 59½, you’ll also have to pay a 10% penalty tax.

Considering these drawbacks to taking out a 401(k) loan, you may want to look elsewhere for money when you need it. But the best time to put away this money is well before you need it. Try to build an emergency fund containing at least six to 12 months’ worth of living expenses, and keep the money in a liquid vehicle. With this money, you’re primarily interested in protecting your principal, not in earning a high return.

A 401(k) is a great retirement savings vehicle. But a 401(k) loan? Not always a good idea. Do what you can to avoid it.


Read more by Jesse Abercrombie

Tags:  Featured  January-February 2013 

Share |
PermalinkComments (0)
 

2013 International President Steve Douglas — IAEI Focuses on 5 Goals for 2013

Posted By Steve Douglas, Tuesday, January 01, 2013
Updated: Friday, December 14, 2012

2013 International President Steve DouglasIncoming International President Steve Douglas has announced five goals for 2013. These undertakings are designed to assist IAEI in taking a giant step forward in membership, in the industry, in technology, in outreach and in establishing real presence in local communities and across the world.

First and foremost, IAEI is continually increasing value for its members. The implementation of a new website and moving towards electronic publications are some of the initiatives for accomplishing this goal.

IAEI codes and standards committee will continue to develop significant code proposals for future editions of both National Electrical Code and the Canadian Electrical Code. Through this process, IAEI members have a strong influence in the North American electrical safety system.

The capital campaign committee, under the leadership of Chuck Mello, will be ramping up its campaign to raise $2 million. Success in this project will ensure appropriate buildings, equipment and technology to allow IAEI to more forward and to be at the forefront of industry ventures.

A special committee has been established to review the international bylaws and operating rules in an effort to reduce duplications and to structure our bylaws in such a way that will allow our organization to be relevant in today’s industry. This fine tuning will enable the association to be more versatile and to respond to partnership and collaboration opportunities in a more timely fashion.

Considerable international interest in IAEI has developed through iaei.org and the social media. As a consequence, a new committee has been established to promote and to assist in the development of chapters and divisions internationally.  

Dave Clements, CEO, welcomes Steve and his background and expertise in electrical codes and standards; he feels confident that these will help Steve guide IAEI in achieving its goals.

About the president

President Steve Douglas joined IAEI in 1990 and attended his first Canadian Section meeting in 1991 in Kingston, Ontario. "At that time,” he recalls, "I did not understand the full impact IAEI has on the electrical safety infrastructure in North America. I was, however, very impressed with the technical program.”

 Photo 1. Stan Benton passes the presidency to Steve Douglas.

Photo 1. Stan Benton passes the presidency to Steve Douglas.

After six years, he was elected to the Ontario Chapter executive and was extremely active at the local level.  In 2001, he was elected to the International Board and has served eleven years, during which he has observed the board become more effective through the use of greater technology, such as web-based meetings, conference calls, and computerization.

 Photo 2. Anita and Steve Douglas

Photo 2. Anita and Steve Douglas

In 1996, Steve had the opportunity to represent IAEI on the Section 8 subcommittee of the Canadian Electrical Code Part I (CE Code). In 1998, IAEI member Roy Hicks, then chief electrical inspector for Ontario Hydro, was able to get an associate member position for IAEI on the CE Code. Steve was placed in this position and within six years was able to change the IAEI status from an associate member to a voting member on the CE Code. Within ten years, he was able to increase IAEI representation on the CE Code subcommittee from 6 subcommittees to all 43 subcommittees for the 2009 edition of the CE Code. IAEI is the first organization to have representation on all 43 sections of the CE Code since the first edition of the CE Code in 1927, and full section representation continued in the 2012 edition.

This Canadian achievement added to IAEI’s current representation in the U.S. on the National Electrical Code — the Technical Correlating Committee and all 19 code-making panels — gives IAEI and its members unique input into the electrical safety infrastructure in North America.

Presently, Steve is the vice chair of the CE Code Part I, chair of CE Code Part I Subcommittees for Section 2, 12, and 50, and a member on Sections 40, 64, 68, 76 and Appendix D. In addition, he is the chair of the CSA Standards C22.2 No. 273 Cablebus, C22.6 No. 1, Electrical Inspection Code for Existing Residential Occupancies committee, the chair of the SPE-1000 Working Group, and a member on committees for the Objective Based Industrial Electrical Code, Safety Management Systems, Solar Photovoltaic Modules, Photovoltaic Cable, Fuel Cells, Wind Turbines, Distribution Transformers, Outlet Boxes, and Wiring Fittings Hardware and Positioning Devices to name a few. In total, he is active on 53 technical codes and standards committees, which gives IAEI recognition on the CE Code and Standards.

Steve lives in Toronto, Ontario, with his wife of 29 years, Anita. They have two daughters. Lindsay and her husband Kevin are the parents of grandson Koen. Penny and Andrew are the parents of granddaughter, Savannah, and grandson, Landyn.

 Photo 3. Daughters Lindsay (left) and Penny (right) with grandchildren (left to right) Koen, Savannah and Landyn.

Photo 3. Daughters Lindsay (left) and Penny (right) with grandchildren (left to right) Koen, Savannah and Landyn.

Steve is currently the senior technical code specialist for QPS Evaluation Services Inc., a certification and field evaluation organization based out of Toronto.

"I am honored to be your international president for 2013, and I look forward to meeting more of you, members of the greatest association dedicated to electrical safety in the world — International Association of Electrical Inspectors,” Steve says.


Read more by Steve Douglas

Tags:  Featured  January-February 2013 

Share |
PermalinkComments (0)
 

Elevator Code and the Building Code — Are these documents in conflict?

Posted By Ark Tsisserev, Tuesday, January 01, 2013
Updated: Friday, December 14, 2012

Photo 1. Typical elevator lightingAfter my recent article on the subject of consistency between the National Building Code of Canada (NBCC) and certain codes and standards referenced by the NBCC, I have received a few e-mails with expressions of frustration and with questions from the readers regarding potential conflict between the NBCC and the Elevator Code ASME A17/CSA B44 harmonized between the USA and Canada.

The main concerns related to the potential conflict between these two documents were expressed by the electrical designers, contractors and inspectors in respect to specific requirements for electrically connected life safety devices and equipment.

So, let’s illustrate some of these concerns in a few examples as follows:

Emergency Operation and Signalling Devices

1. Section 2.27 of the Elevator Code - CSA standard B44 covers "Emergency Operation and Signalling Devices.”

 Note in the Elevator Code states the following: "additional requirements, including those for fire-fighters’ communication systems, may be found in the building code.”

Subsection 2.27.1 provides requirements for "Car Emergency Signalling Devices.” It is interesting to review the language of Clauses 2.27.1.1.1 and 2.27.1.1.2 for their consistency with the NBCC (with the document that might have additional requirements, as indicated in Note on Section 2.27).

Clause 2.27.1.1.1 requires that "A two-way communication means between the car and a location staffed by authorized personnel shall be provided.” This Clause is silent on the specifics where actually such "location staffed by authorized personnel shall be provided.” Before we’ll explore the provisions of the NBCC in this regard, let’s take a look at Clause 2.27.1.1.2 that continues to address two-way communication requirements between the elevator car and the location staffed by authorized personnel. This Clause mandates that:

(a) Two-way communications shall be directed to a location(s) staffed by authorized personnel who can take appropriate action;

(b) If the call is not acknowledged within 45 s, the call shall be automatically directed to an alternate on- or off-site location.

Some users of the Elevator Code are under the impression that such "location staffed by authorized personnel” must be provided in the building equipped with an elevator. However, in reality, it is impracticable to expect such staffed location in a typical 3 or 5 storey residential or office building or even in an office or residential hi-rise building where dedicated authorized concierge or security staff does not exist.

Now is the appropriate time to find out what the NBCC mandates on this subject. Sentence 3.2.6.7.(2)(j) of the NBCC states that the Central Alarm and Control Facility (or CACF in abbreviated form) installed in a building must be provided with "means to communicate with telephones in elevator cars, separate from connections to firefighters’ telephones, if elevator cars are required by CSA B44,” Safety Code for elevators, "to be equipped with a telephone.” But what does Central Alarm and Control Facility or CACF mean?  And is the NBCC requirement for a CACF applicable for every building?

The review of the NBCC clearly demonstrates that a CACF is a very specific infrastructure of equipment and controls dedicated to supervisory, annunciating, control and communication functions that must be provided on the storey containing the entrance for the fire respondents to the building, and that such CACF is only required to be installed in buildings that are defined by the NBCC as "high buildings.”  In all other buildings, installation of a CACF is not required by the NBCC, and of course ability to establish "location staffed by authorized personnel” in a building is not practicable for majority of building projects. So, does this particular example mean that the Elevator Code requirements are in conflict with the NBCC?  

Not necessarily. The B44 requirement that "location staffed by authorized personnel shall be provided” simply means that the designers should specify a need for a communication between telephones in the elevators cars and a central station that monitors building fire alarm system (or between telephones in the elevator cars and any other communication facility staffed with authorized personnel).

The objective of this Elevator Code requirement is to articulate a need to receive the signal from elevator cars telephones, to process it and to respond to this call by the authorized personnel of the staffed communication facility, when a person in distress located in the elevator picks up the elevator car phone and makes this call. Unfortunately, some designers overlook this requirement of the B44, and some AHJs never audit compliance with this requirement during a coordinated life test or during the test of the elevator operation.

Emergency Recall Operation

2. Clause 2.27.3.2.2 of the B44 mandates the following requirements for Phase I Emergency Recall Operation of Elevators by Fire Alarm Initiating Devices.

2.27.3.2.2 In jurisdictions enforcing the NBCC, smoke detectors, or heat detectors in environments not suitable for smoke detectors (fire alarm initiating devices), used to initiate Phase I

Emergency Recall Operation, shall be installed in conformance with the requirements of the NBCC, and shall be located

(a) at each floor served by the elevator

(b) in the associated elevator machine room, machinery space containing a motor controller or electric driving machine, control space or control room.

Perhaps, to re-phrase this requirement, it is appropriate to mention the following:  B44 simply states that if an elevator equipped with the automatic emergency recall feature is installed in any building (regardless of the building height or building occupancy classification), at least one smoke detector must be provided in the elevator machine room and at each floor in the elevator lobby served by this elevator — in order to initiate automatic emergency recall operation of the elevator to the recall level.

It should be noted that the number of smoke detectors that have to be located in each specific area where smoke detectors are mandated by the Elevator Code or by the NBCC should be determined based on provisions of the ULC S524 (One smoke detector usually covers an area not exceeding 81 sq. m.). It is also interesting to note that this particular B44 requirement references the NBCC as the Code that mandates installation of smoke detectors in those specific locations (see italicized portion of the quoted Clause 2.27.3.2.2 above).

Now is the perfect opportunity to review the NBCC provisions in this regard.

The 2010 edition of the NBCC has been revised to reflect the Elevator Code requirements for the automatic emergency recall of elevators by dedicated smoke detectors. However, despite new NBCC revisions on this subject, a full consistency of the NBCC with the Elevator Code has not been achieved.

New Sentence 3.2.4.12.(1)(g) of the NBCC mandates installation of smoke detectors in elevator machine rooms.

New sentence 3.2.4.12.(4) of the NBCC states the following: "3.2.4.12.(4) Smoke detectors required by Clause (1)(g) shall, upon actuation, recall the elevators served by the elevator machine room in which the smoke detector is installed.”  So far, so good. It looks like there is a consistency between the B44 and NBCC on this matter. But, what about the B44 requirement for installation of smoke detectors at each floor, in order to initiate automatic emergency recall of the elevators serving the elevator lobby of the floor where the smoke detector is actuated? Unfortunately, the expected consistency between these two codes has not happened. Article 3.2.4.15. of the NBCC offers the following requirement in this regard:

3.2.4.15. Elevator Emergency Recall

 (1) Except as permitted by Sentence (3), in a building having elevators that serve storeys above the first storey and that are equipped with an automatic emergency recall feature, smoke detectors shall be installed in the elevator lobbies on the recall level so that when these smoke detectors are actuated, the elevators will automatically return directly to an alternate floor level.

(2) Smoke detectors required by Sentence (1) shall be designed as part of the building fire alarm system.

(3) The alternate recall feature required by Sentence (1) is not required if the floor area containing the recall level is sprinklered throughout.

As it can be seen from the above NBCC provision, it does not match the B44 requirement for unconditional installation of smoke detectors in an elevator lobby at each floor of any building where elevators are provided, and these elevators are equipped with the automatic emergency recall feature.

Some local building codes try to match the B44 provisions by revising requirements for actuation of the automatic emergency recall of elevators by the smoke detectors installed in the elevator lobbies.

For example, the Vancouver Building By-Law (VBBL) has been revised accordingly to mandate such automatic emergency recall of the elevators. However, such revision in the VBBL is limited only to the elevators installed in high buildings covered by provisions of Subsection 3.2.6. as follows (it should be noted that only relevant provisions of Article 3.2.6.4. of the VBBL are quoted below):

3.2.6.4. Emergency Operation of Elevators

(1) Automatic and manual emergency recall shall be provided for all elevators serving storeys above the first storey.

(5) The automatic emergency recall requirement in Sentence (1) shall be activated by

(a) smoke detectors installed in each floor area in front of the elevator or elevators, or

(b) the building fire alarm system.

(6) Where smoke detectors, as provided by Sentence (5), are activated on the recall level a signal shall automatically direct the elevator to an alternate floor level.

(7) Smoke detectors in Sentences (5) and (6) shall be designed shall be designed as part of the building fire alarm system

So, what should a designer do in light of such inconsistency between the NBCC and B44? 

In my view, the provisions of B44 should be utilized in the electrical design, as these B44 provisions (although not necessarily consistent with the Building Code) do not in a conflict with the NBCC, but simply supplement the NBCC as the additional fire safety requirements. 

 Fire Detectors in Elevator Shafts or Pits

3. What about the requirements to install fire detectors in the elevators shafts or elevator pits?

Sentence 3.2.4.11.(2)(e) of the NBCC clarifies the requirement for fire detection in an elevator shaft by stating that a fire detector (a smoke detector or a heat detector) must be located in an elevator hoistway. Sentence 3.2.4.11.(4) of the NBCC explains that if an elevator hoistway is sprinklered, then the fire detectors mandated by Sentence (2) are not required. This means that a separate flow detecting device (a dedicated flow switch) must be provided for a sprinkler system installed in the elevator hoistway; as in accordance with Article 3.2.4.16. of the NBCC, a flow switch monitoring a sprinkler system on a typical floor must be installed so that such flow switch covers a sprinkler system for the area not exceeding that particular floor.

However, the NBCC or the B44 do not mandate installation of fire detectors in an elevator pit. In fact, practice of installation of fire detectors in elevators pits has demonstrated numerous problems with the operation and maintenance of these fire detectors, and voluntary installation of fire detectors in elevator pits would be inconsistent with good engineering design and good engineering practice.

Lighting Requirements for Specific Areas

4. And what about lighting requirements for specific areas related to elevators? The NBCC does not provide any particular guidance in this regard.

Nevertheless, Clause 2.7.9.1 of the Elevator Code states that "Permanently installed electric lighting shall be provided in all machinery spaces, machine rooms, control spaces, and control rooms.” After making this profound statement by listing all the areas where lighting is required, the B44 confuses the Code users in Clause 2.8.2.2 that governs provisions for Electrical Equipment and Wiring, as this Clause states the following (see italicized portion of the Clause below):

2.8.2.2 Only such electrical wiring, raceways, cables, coaxial wiring, and antennas used directly in connection with the elevator, including wiring for signals, for communication with the car, for lighting, heating, air conditioning, and ventilating the car, for fire detecting systems, for pit sump pumps, and for heating and lighting the hoistway and/or the machinery space, machine room, control space, or control room shall be permitted to be installed inside the hoistway, machinery space, machine room, control space, or control room.

It looks like the B44 Clause that governs only the electrical equipment and wiring inadvertently implies that the elevator hoistway must be provided with lighting as well (in addition to the locations listed in Clause 2.7.9.1).

So, the examples illustrated above demonstrate that some aspects of the B44 and the NBCC are not necessarily in conflict, but other provisions of these codes could create a problem to the users if the inconsistent requirements in both codes are not discussed with the applicable AHJs before design and installation are completed.

Therefore, as usual, the relevant authorities with the jurisdictional power for administration of the B44 and the NBCC must be consulted at the design stage of any electrical project.


Read more by Ark Tsisserev

Tags:  Canadian Perspective  January-February 2013 

Share |
PermalinkComments (0)
 

Cablebus

Posted By Steve Douglas, Tuesday, January 01, 2013
Updated: Friday, December 14, 2012

The new standard for cablebus C22.2 No 273 is scheduled for publication by September of this year. This new standard will be the first standard for cablebus in North America. The committee includes the six major cablebus manufacturers in North America, two switchgear manufacturers, CSA, and an IAEI representative. 

Cablebus is an assembly

Cablebus is an assembly of insulated conductors with fittings and conductor terminations in a completely enclosed, ventilated, or non-ventilated protective metal housing. In most cases, cablebus will be approved by either certification or field evaluation and is typically assembled at the point of installation from the components furnished by the cablebus manufacturer. Accompanying the cablebus, the manufacturer will provide installation instructions and drawings for the specific installation to facilitate:

a) system design;

b) construction;

c) fire stop rating (where applicable);

d) weatherproof entrance fittings (where appli-cable);

e) bonding, conductor and shield terminations (where applicable);

f) grounding of shields (where applicable) and installation;

g) inclusion of electrical detail of the conductor configuration, together with enclosure dimensions;

h) specification of maximum allowable span support; and

i) vertical installations.

Cablebus nameplate

To assist the electrical contractor and electrical inspector the main nameplate will include:

a)   The manufacturer’s name, trademark, or other descriptive marking by which the organization responsible for the product can be identified;

b)   The electrical ratings:

– rated nominal voltage, (Vrms or Vdc)

– frequency in Hz

– allowable ampacity  (Amps),  based on ambient temperature* of XX*C, and based on a maximum operating temperature of XX*C- short circuit current rating  

– number of phases (poles for dc);

– 3-wire or 4-wire; and

–Maximum continuous current rating _XX_A, when connected to a 100% continuous rated overcurrent device

– Maximum continuous current rating _XX_A, when connected to a 80% continuous rated overcurrent device

*Note: the temperature is the maximum ambient temperature that the equipment was designed to operate in.

c) The month and year of manufacture, at least, shall be marked on the cablebus system in a location accessible without the use of tools.

d)   The number of conductors and size per phase.

e) As a minimum, the allowable ampacity (amps) based on a maximum operating temperature of 75°C  shall be included on the nameplate.

f) Type of material, such as stainless steel (including the type), aluminum, etc., and, if carbon steel, Type 1 (hot-dip galvanized), Type 2 (mill galvanized), or Type 3 (electrodeposited zinc), as applicable. If the manufacturer’s catalogue number marked on the product would readily lead the user to the required information published by the manufacturer, this marking is not mandatory;

g) a warning label that reads, "WARNING! DO NOT USE AS A WALKWAY, LADDER, OR SUPPORT FOR PERSONNEL; and

h) the design drawing number for the specific installation.

Maximum continuous current rating

The maximum continuous current rating will assist in the application of CE Code Rules 12-2260 and 8-104 and help provide consistency with respect to conductor loading. In addition to these nameplate markings, cablebus will be one of two classes corresponding with the Items (a) and (b) in CE Code Rule 12-2252. CE Code Part I Rule 12-2252 states:

12-2252 Use of cablebus (see Appendix B)

Cablebus shall be permitted for use where

(a) protection from contact with conductors is provided by design and construction of the enclosure; or

(b) installation is intended in areas

(i) accessible only to authorized persons;

(ii) isolated by elevation or by barriers; and

(iii) where qualified electrical maintenance personnel service the installation.

Class A cablebus is designed with protection from conductors contact provided by the design and construction of the enclosure. Class B cablebus is intended to be installed in areas accessible to authorized persons, isolated by elevation or by barriers, and where qualified electrical maintenance personnel service the installation.


Steve Douglas is presently the senior technical codes specialist for QPS Evaluation Services. As the International Association of Electrical Inspectors representative on Part I and Part II of the Canadian Electrical Code, Steve is the vice chair of the CE Code Part I, chair of CE Code Part I Subcommittees for Section 2, 12, and 50, and a member on Sections 40, 64, 68, 76 and Appendix D. In addition, Steve is the chair of the CSA Standards C22.2 No. 273 Cablebus, C22.6 No. 1, Electrical Inspection Code for Existing Residential Occupancies committee; the chair of the SPE-1000 Working Group; and a member on committees for the Objective Based Industrial Electrical Code, Safety Management Systems, Solar Photovoltaic Modules, Photovoltaic Cable, Fuel Cells, Wind Turbines, Distribution transformers, Outlet Boxes, and Wiring Fittings Hardware and Positioning Devices. 

Tags:  Featured  January-February 2013 

Share |
PermalinkComments (0)
 

Article 240, Part 1 — Overcurrent Protection

Posted By Randy Hunter, Tuesday, January 01, 2013
Updated: Friday, December 14, 2012

Overcurrent protection is a subject on which we could write volumes; however, our objective here is to cover the basics in order to provide the information needed for the combination inspector. This is actually a fun portion of training, as we usually take apart devices and explore how they operate. Check out the included photos that illustrate some of the details that we usually look at in training classes, and don’t be hesitant about disassembling equipment (that you don’t plan to install later!) to see what is inside. 

To make sure we understand our topic, we need to start with the scope of this article. It provides the general requirements for overcurrent protection and overcurrent protective devices not more than 600 volts, nominal. There are two parts to Article 240 that we will not address: Part VIII dealing with supervised industrial installations and Part IX dealing with over 600 volts. Combination inspectors are generally not involved with these installations, so we will leave those topics to articles and books specifically concerned with those subjects.

 Photo 1. Overcurrent protection comes in many types, sizes and shapes

Photo 1. Overcurrent protection comes in many types, sizes and shapes

As with most NEC articles, we need to start with some unique definitions. Article 240 has only three definitions, and they are located in 240.2. First we have a definition of current-limiting overcurrent protective device, which is a device that when interrupting currents in its current-limiting range will reduce the current flowing downstream to a level much less than if there were just a solid conductor having comparable impedance. Current-limiting devices are very instrumental in reducing incident energy (arc flash, arc blast) in our electrical systems, making them safer for personnel and providing protection of equipment.

The second definition deals with a term that is also used in other parts of the code. Quite often we have a question as to what exactly is an "industrial installation”? In 240.2, we have a definition of supervised industrial installation with a list of conditions which must be met to fall under this definition. Note that this definition is specifically limited to use in Part VIII of Article 240; this means that these limitations do not apply to any other code provision where supervised industrial installation (or similar term) is used. You can’t use this definition when applying 392.10(B), for example, which allows certain cable tray wiring methods in industrial establishments. Since we are not covering Part VIII in depth, I simply point this out so that you know that this definition is very limited in application.

 Photo 2. Here is a very good example of a neutral main bonding jumper that was never properly connected after the completion of the ground fault testing. This caused several problems within this facility, including voltage fluctuations and equipment failures.

Photo 2. Here is a very good example of a neutral main bonding jumper that was never properly connected after the completion of the ground fault testing. This caused several problems within this facility, including voltage fluctuations and equipment failures.


The last definition is that of a tap conductor as used in this article. This definition is needed as we have various tap rules within Article 240 with very specific rules. Simply put, a tap conductor is a conductor other than a service conductor that has overcurrent protection ahead of it which is oversized compared to the normal requirements found in Article 240.

Basic minimum overcurrent protection

So, let’s get down to the most basic of rules for overcurrent protection. The go-to article here is 240.4. Other than flexible cords, flexible cables and fixture wire, we refer to the ampacities of the conductors as specified in Article 310.15, unless covered in specific applications as described in 240.4(A) through (G). In these subparagraphs, we cover basic minimum overcurrent protection device sizing according to conductor sizes and properties. These are very basic rules that will at times get overlooked when using ampacity tables, but you absolutely need to try to commit these to memory. Also, many code test questions will ask about sizing a certain type and size conductor, and you’ll get sidetracked into doing a calculation and don’t want to forget that you have limitations in 240.4. Please review these and remember some basic ones such as 14 AWG copper must have 15 amp protection, 12 AWG copper is limited to 20 amps and 10 AWG copper at 30 amps, just to name a few.

There are two very important rules in 240.4 that we have to examine more closely, as they deal with protection for 800 amps and lower and then over 800 amps. These general rules state that if you are sizing protection for 800 amps or lower, you are allowed to round up to the next largest device, as long as you don’t violate the specific conductors mentioned in 240.4(D). If you have a system over 800 amps, then the ampacity of the conductors has to equal or exceed the rating of the overcurrent device.

 Photo 3. This is a photo showing the interior of a 600-amp fuse after the sand filler has been removed.  This fuse opened during an overload condition.   You can see how five of the six alloy contact points melted and released; when the last one interrupted the flow of current, it arced and caused the burned sixth contact.  Please note in the left photo you can see the short-circuit elements which are still intact; these are the webs which melt out during a high fault current condition.

 Photo 3. This is a photo showing the interior of a 600-amp fuse after the sand filler has been removed.  This fuse opened during an overload condition.   You can see how five of the six alloy contact points melted and released; when the last one interrupted the flow of current, it arced and caused the burned sixth contact.  Please note in the left photo you can see the short-circuit elements which are still intact; these are the webs which melt out during a high fault current condition.


The next question that usually comes up here is: When allowed to round up to the next size device, what is the next size? The next size according to what is available from the manufacturer? No, you round up to the next standard size device according to 240.6. Please notice that in 240.5 you will find the specific overcurrent sizes for flexible cord, cables and fixture wire; again, the rules are very specific and in part mention exact size overcurrent protection according to the wire size. Please review, but know that generally speaking, we don’t see these wire types that often in combination inspections.

Standard ampere ratings

Let’s go back to Standard Ampere Ratings in 240.6. This is one section of your code book you will need to reference almost as often as conductor ampacities, so please remember it. Here you find what the code considers "standard sizes” when references are made to sizing overcurrent devices. I always make a big point of making sure everyone uses the sizes listed in this article when working on code questions or test questions. Another note here, remember when we had the rule that you round up when working at 800 amps and below? Well, you will notice the size differences below 800 amps are much closer, so when we round up it’s not much of a shift; however, when you get over 800 amps you will notice there are not as many options and the sizes start to jump in pretty large increments. This helps to explain the reasoning behind this code requirement, since rounding up in such large steps could lead to a large disparity between conductor ampacity and overcurrent protection levels.

Also in 240.6 are two paragraphs, (B) and (C), which work together to address adjustable trip circuit breakers. If you have an adjustable breaker which has the adjustment exposed with ready access, then the rating of that breaker will be the maximum possible setting. However, if these controls have a restricted access feature meeting the requirements as set forth in (C), then the rating of this device will be at the set value. The one gray area here is that some of the breakers have a field-fitted rating plug. It was my opinion as an inspector that if this plug type device could not be removed without the removal of sealable covers or special tooling of some sort, we applied 240.6(B). One such case had a plug which could easily be removed using a pair of needle nose pliers, so we opted for the conservative approach and applied (C).

 Photo 4. This photo shows the inside of a breaker. You can see some of the mechanical parts that are required for proper operation.

Photo 4. This photo shows the inside of a breaker. You can see some of the mechanical parts that are required for proper operation.


Fuses or circuit breakers in parallel

Questions appearing on some tests ask if it is permissible to use fuses and circuit breakers in parallel. This is addressed in 240.8. The correct answer is: only where they are a part of a factory assembly and listed as a unit. I have seen this from time to time, but never outside a factory listed unit.

Electrical system coordination

Continuing on, 240.12 starts us on the path for an interesting concept that often isn’t considered in design. The subject is electrical system coordination, and it simply states that to minimize hazard(s) to personnel and equipment where an orderly shutdown is required, a system of coordination based on two conditions shall be permitted. The first condition is coordinated short-circuit protection and the second is overload indication based a monitoring system or devices. Notice that this language says "shall be permitted.” This means that is allowed, but not required. This language is generally applied to situations where it is more hazardous to shut down the electrical source than it is to shut down the process. This is not the same as selective coordination, which is required for many emergency systems and will be covered when we finally get to Chapter 7.

Ground-fault protection of equipment

In 240.13 we find requirements for Ground-Fault Protection of Equipment. Let’s first consider the difference between ground-fault circuit interruption (GFCI) and ground-fault protection. The easiest way to explain this is that GFCI protection is for people and the threshold levels are extremely low (around 5 ma), whereas the protection of equipment is meant to minimize the damage to equipment in the event of a fault condition to ground. This applies to only a very specific power configuration and that is a solid wye-connected system, where the voltage to ground is more than 150 volts and the phase-to-phase voltage does not exceed 600 volts. Commonly this will be our 277/480 volts wye-connected three-phase systems that are 1000 amperes or more in size. Ground-fault protection offers a level of protection in the event of a ground fault at a much lower level of current than what the breaker is equipped to handle under normal operation. I’ll tell you a personal experience related to this. We had a bank in our jurisdiction where the service was rated at 1000 amps, 277/480 and so the inspector made a note that this installation would require ground-fault protection. The engineer stated it didn’t need it because he had specified an 800-amp main breaker. A little gray area I guess, but we decided to stick with the rating of the manufacturer’s label which stated the service equipment was 1000 amps. The end result was that the factory sent out new equipment labels and had a field inspection done by a listing agency to change the equipment to an 800-amp service officially.

Ground-fault protection needs a little deeper look, first to understand how it works and then to understand some of the complexities to look for as you are doing your inspections. First, these devices have a sensing ability to verify that the amount of current being called for is balanced and all accounted for between the other phases or the grounded conductor. In the event that we have current going to ground or not following the normal paths, then the ground-fault protection will open the device (this could be a breaker or a bolt switch equipped with the ground-fault protection). When these devices are sent out, they are set at factory minimums. If the levels are not adjusted at the time of installation, this minimum setting may cause nuisance tripping. The setting should be evaluated and specified by the engineer of record, and then set in the field to match the engineer’s design.

Once I got a service call for a large grocery store that had lost power. The main at this store had ground-fault protection, and the original contractor didn’t set up the device as requested by the engineer of record. So, it was still set at the minimum value. On the evening I got the call, the manager had asked a box boy to paint the hallway going upstairs to the break room, and the young man had saturated his roller to the point it caused some large drips to start running down the wall. The paint flowed into a 277-volt switch box and shorted out the switch. Well before the individual circuit breaker which fed the lighting circuit could interrupt the fault, the ground-fault device saw the fault to ground, did its job, and shut down the entire store. Because the device was not properly set by the installer, the entire facility lost power.

 Photo 5. This collage of photos shows a before-and-after for breakers.  The top row shows a breaker which has not been in operation.  The left and middle photos show both sides of the contacts, and the right photo shows the arc chutes.  The bottom row shows an example of the same parts of another breaker which has been subjected to a high fault current condition and had to open, causing damage to its components.

Photo 5. This collage of photos shows a before-and-after for breakers.  The top row shows a breaker which has not been in operation.  The left and middle photos show both sides of the contacts, and the right photo shows the arc chutes.  The bottom row shows an example of the same parts of another breaker which has been subjected to a high fault current condition and had to open, causing damage to its components.


Total separation of grounds and neutrals

Now one of the critical items we must look at during inspection is the total separation of grounds and neutrals downstream of the ground-fault device. This must be done all the way throughout the system down to each branch-circuit device and the equipment connected to the system. At the main service we have to pay special attention to have the grounds connected only to the grounding bar, and neutrals connected only to the neutral bar. Now this is different from our normal method, say in a residential main panel, where we can just mix the grounds and neutrals as we see fit. In these larger systems, there is a neutral bonding jumper (which could be a conductor but is generally a piece of busing) that comes from the factory and is not connected to the ground bar. As an inspector, you have to verify that the grounds terminate on the ground bar and the neutrals, to the neutral bar. If these are not done properly, the system will have issues.

Locally we always required third party verification and testing of the ground-fault system before we would approve it to be energized. This was our insurance that the unit had the grounds and neutrals separated throughout the entire facility and that the system wasn’t left at factory minimums. Once the system has been checked, then the neutral bonding jumper is connected between the neutral and the ground bar. So after we got this report, we would make sure the bonding jumper link was connected between the neutral and ground bar and then allow the contractor to have the system energized. This was our solution for enforcement of ground-fault protection of equipment.

In the next issue we will pick up with Part II of Article 240, but this is a good time to cover a related issue. While teaching classes on the code, I always tried to take the mystery out of the electrical system as much as possible. So I am going to spend a little time explaining how overcurrent and short-circuit protection works. In class this always led to a lot of show and tell, taking apart devices and physically seeing their operation. I will try to explain this here and supplement it with some good photos.

Basics of circuit protection

We need to explore some of the basics of circuit protection. First we’ll start with the most common circuit breaker in the industry today, that being an inverse time circuit breaker. These come in all sizes and ratings, from 15 amps and up. They are rated by amperage, voltage and interrupting rating. The first two items we should already be familiar with; however, the last is often overlooked. The interrupting rating is the amount of fault current the device is able to safely handle without catastrophic failure. Insuring the available fault current is less than the rating of the device is one of the inspection items we need to look for. Breakers are mechanical equipment; similar to any other mechanical device, they require a lot of pieces to work together with the proper timing to do their job. A car is a good comparison, as it is a mechanical device that has many pieces that have to operate in a certain sequence for proper operation. Also similar to cars, the need for exercise and maintenance for breakers should be considered. Inside a breaker we have two distinct methods which cause it to open, one being an overload which is normally up to about 6 times the handle rating, and the other being the short-circuit portion which reacts to shorts causing a high level of fault current to flow. The overload is normally handled by a bi-metallic element which when exposed to excessive current starts to heat up and it then deflects to contact the trip bar and release the trip mechanism. Breakers handle short circuits with a magnetic sensor which reacts to high current flow and opens a breaker as fast as it can. Remember these are mechanical, and as such they take a certain amount of time to react and then to complete the operation of shutting down the circuit. The photos illustrate the number of components inside a breaker and also show a close up of the contacts, the arc shields which control and manage the arcing when operating in high-fault conditions, and a bi-metallic strip.

The other most common method of circuit protection is fuses, which in many circles is considered old style due to the fact they’ve been used to protect electrical systems practically since the beginning. However, they still have a distinct use in today’s systems and provide some very unique methods of protection due partially to their simpler operation. The most commonly used fuse for construction is a dual element time-delay fuse. These have two distinct portions within each fuse; the first portion is a thermally reactive element which handles an overload situation. This element uses a melting alloy which has been specifically created for each size fuse. When it is exposed to an overload condition it will melt out and release, allowing the fuse to open. The short-circuit section of a  fuse consists of a web-style design which is designed to react to high-current flows and very rapidly melt out; as these melt and break away, the amount of metal mass left is diminished which limits the amount of current which can continue to pass through the fuse. Therefore, they are considered current-limiting by design. In order to control this arcing within the fuse, it is filled with sand. When the sand comes into contact with the extreme heat and arcing of the webs, it turns into glass to quench the arcing event and extinguish it.

I know the operation of a fuse sounds basic compared to a device full of mechanical components which have to work in unison, but that’s just how simple they are. Once a fuse opens, you replace them with a new fuse which restores the system back to its original level of protection. When a breaker has been subjected to fault current near its operating limit, it should be taken out of service and tested before using again. There are companies that test breakers to insure they operate in the proper time and current levels required and then re-certify them. If the breaker is not tested and re-certified, it may not protect the system during a future fault.

In the next issue we will continue with Article 240. Continue to review the code as these articles only cover the highlights you need to know.


Randy Hunter works for Cooper Bussmann.  He holds twelve inspections certifications from IAEI, ICC and IAPMO. Randy is IAEI Southwestern Section secretary, Southern Nevada IAEI Chapter president, a current member of CMP-17, voting member of UL 1563, Electric Spas, Equipment Assemblies, and Associated Equipment, and a former principal member of CMP-6. He has served on several Southern Nevada local code committees and electrical licensing committees. He has been a master electrician since 1988, and pri­or to that he designed and built computed numerically controlled (CNC) machine tools. 

Tags:  Featured  January-February 2013 

Share |
PermalinkComments (0)
 
Page 8 of 111
 |<   <<   <  3  |  4  |  5  |  6  |  7  |  8  |  9  |  10  |  11  |  12  |  13  >   >>   >|