Posted By Ark Tsisserev,
Thursday, November 01, 2007
Updated: Saturday, February 09, 2013
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It is very reassuring for a feature columnist to know that his articles are actually read and discussed by the readers. I was pleased to get comments from the Canadian readers of the IAEI News on my column published in the July/August issue (page 38). That column described a comprehensive process developed by the CSA for proposals to change the Canadian Electrical Code. Yet, the same readers have pointed out to me that perhaps Bob Edwards is not aware of this process, as his article on "inadequacies” of Rule 8-104 in the CE Code (shown on page 12 of the same issue) painted a bleak picture of this rule.
I’d like to assure these readers that Bob Edwards is well aware of the CSA process, as he was an active member of the Technical Committee responsible for the development of the Canadian Electrical Code for many years. As chair of this Technical Committee, I’m certain that Bob’s (and anyone else’s) proposal would be expediently considered by his peers via a CSA consensus process, provided that all relevant conditions for a proposal (as indicated in my earlier article) are, in fact, met.
However, let’s look at Rule 8-104 and evaluate its requirements.
This rule governs provisions for selection of ampacity of conductors for a branch circuit (or service, feeder) and for selection of the overcurrent devices that protect these conductors. Such selection is based on the calculated load, and Rule 8-104 establishes a relationship between a calculated load and a rating of a circuit (or service, feeder). This rule also explains the meaning of the "ampere rating of the circuit” and describes types of calculated loads (continuous and non-continuous). Let’s take a close look at this rule.
In general, this rule proposes two following principles: 1) the load cannot exceed the ampacity of circuit (service, feeder) conductors that are intended to carry the load; and 2) the load cannot exceed the rating of the overcurrent devices that are intended to protect these circuit (service, feeder) conductors.
In fact, these main principles are articulated in Rule 8-104(2) which states that the "calculated load in a circuit shall not exceed the ampere rating of the circuit.”
Subrule 8-104(1) further clarifies description of the "ampere rating” of the circuit (service, feeder) as the "ampere rating of the overcurrent device protecting the circuit or the ampacity of the conductors, whichever is less.”
This means that if, for example, a branch circuit (feeder or consumer’s service) has the o/c device rated at 200 A and 3/0 AWG copper conductors selected from column 4 of Table 2 at 210 A, the ampere rating of such a branch circuit (service, feeder) is 200 A, and not 210 A, as 200 A is less than 210 A.
So far, things look relatively simple, but Subrules 8-104(3), 8-104(4) and 8-104(5) place additional conditions on the criteria for selecting the ampere rating of a circuit. These new conditions force the Code users to determine whether the calculated load must be considered as a continuous load [Rule 8-104(3)], and then to ascertain that the continuous load of the circuit (service, feeder) is not only less than the ampere rating of that circuit, but is actually less than a particular percentage of the circuit rating. And, the Code specifies the maximum allowable percentage by which the continuous load can relate to the ampere rating of the circuit.
Let’s step back, however, and analyze this new term continuous load. Subrule 8-104(3) states that each calculated load shall be considered to be a "continuous load” unless it can be clearly demonstrated that in normal operation this load will not be applied for: 1) a total of more than 1 hour in any two-hour period, provided that the value of the load does not exceed 225A; or 2) a total of more than 3 hours in any six-hour period provided also that the load does not exceed 225A.
It is interesting to note that the Code allows loads of a dwelling unit to be treated as non-continuous loads for the purpose of Rule 8-104. This consideration is provided by Rules 8-200(3) and 8-202(2) of the CE Code. All other loads, however, are deemed to be continuous, unless provisions allowed by Subrules 8-104(3)(a) or (3)(b) could be demonstrated to the AHJ.
Thus, when a load calculation is done for a single dwelling (Rule 8-200) and the calculated load, for example, yields 92 A, then in accordance with Subrule 8-104(2), the ampere rating of the service can be chosen by selecting standard values of the o/c device and the ampacity of the service conductors which are not less than the calculated load. It is obvious that the ampere rating of the consumer service, for this example, would be 100 A. The service conductors would be selected based on this calculated load from Tables 1–4 accordingly. If for the purpose of this example Table 4 is used to select the service conductors, the Code users should note that although the ampacity of 2 AWG AL conductors is shown in column 4 of Table 4 as 95 A, Note ** on this table indicates that when this conductor size is used to supply single dwellings, the ampacity of 2 AWG AL conductors in a 3-wire 120/240 V or 120/208 V service is considered to be 100 A. So, 2 AWG AL could be used for this service—to supply the non-continuous calculated load of the single dwelling.
Now let’s deal with those loads that are considered to be continuous. In this case, two options are entertained by the Code.
The first option is provided by Subrule 8-104(4). This subrule governs those situations when the o/c device in a service box, switch, or in a combination panelboard is specifically marked for continuous operation at 100% of this o/c device rating. From a practical point of view, this means that each o/c is specifically designed, constructed and tested for 100% continuous operation of its ampere rating. In this case, Subrule 8-104(4) allows us to select the rating of the circuit (feeder, service) protected by such o/c devices based on the 100% of the rating of the circuit (based on the applied calculated load similarly to the example above for a single dwelling), provided that the ampacity of conductors is chosen in accordance with Table 2 or 4. If, however, the Code user intends to apply Table 1 or 3 (free air rating) for selection of the circuit conductors, then respectively the continuous load as determined from the calculated load cannot exceed 85% of the circuit rating. For example, if a branch circuit carrying a continuous calculated load of 85 A is intended to be protected by the o/c device marked for continuous operation at 100% of its rating, and conductors are intended to be selected based on Table 2, then the o/c device with the standard setting of 90 A (see Table 13) could be installed, and 4 AWG copper (85A) could be selected from column 4 of Table 2.
If, for example Table 1 is intended to be used (free air rated conductors), then the o/c device marked for continuous operation at 100% of its rating must be not less than 100 A; and a 6 AWG copper conductor shall be chosen from column 4 of Table 1.
The second option is described by Subrule 8-104(5). This subrule governs those cases (the most common) where the o/c device protecting the circuit (service, feeder) is not specifically marked for continuous operation at 100% of its rating (when an o/c device was designed, constructed and tested for continuous operation at 80% of its ampere rating). In this case, the continuous load as determined from the calculated load cannot exceed 80% of the rating of the circuit if ampacity of the circuit conductors are based on Table 2 or Table 4. For example, a circuit rated at 200 A cannot be used for supply of a continuous calculated load in excess of 160 A.
If, however, Table 1 or 3 is used for selection of conductors (free air ampacity), then the continuous load as derived from the calculated load cannot exceed 70% of the ampere rating of the circuit. In this case, a continuous load of a typical branch circuit rated at 200 A (the o/c device rated at 200 A and the conductors with ampacity at 210 A selected based on Table 2) cannot exceed 140 A.
Rule 8-104 applies conditions that are outlined in Subrules (4) and (5) as a benchmark for all other calculations, where applicable derating factors are used to reduce the conductor ampacity [see Subrules 8-104(6) and (7)].
It should be also noted that another main principle that establishes a relationship between ampacity of circuit conductors and the rating/setting of the o/c devices protecting these conductors is described in Rule 14-104. This rule states, "the rating or setting of overcurrent devices shall not exceed the allowable ampacity of the conductors that they protect,” unless otherwise permitted by Table 13 or other rules of the Code [i.e., rules such as 26-208 and 26-210; 28-106 and 28-200; 32-200 and 32-206; 62-114 (7), etc.].
I hope that this article clarifies the "mystery” behind circuit loading. In each particular case, however, specific concerns and questions related to this subject should be discussed with the authorities enforcing the CE Code.
I’m certain that any constructive proposal to improve this rule by including necessary derating factors when selection of conductors is based on IEEE 835 for underground runs of conductors would be welcomed by the CE Code Committee.
Read more by Ark Tsisserev
Posted By David Young,
Thursday, November 01, 2007
Updated: Saturday, February 09, 2013
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Alternative electric sources have been around for a long time. I have a sister-in-law who lives on the side of a mountain near Rutland, Vermont. She built her house about the time of the first energy crunch in the mid-seventies. She and her husband decided not to connect to the local electric utility. For over thirty years, they have generated all of their electricity for their house and businesses (production of maple syrup and engineering consulting) from solar panels on the roof of their house and a small windmill located several thousand feet from their house. So why don’t more people do it? When I ask people this question, they usually answer, "It’s not economical.”
When I ask them, "How do you know that?” They usually answer, "If it were economical, everyone would do it.” So when is it economical? If the manufacturers of solar panels guaranteed that their panels would pay for themselves in four years, I think we would soon see most of our roofs covered with solar panels. At this point, however, solar panels manufacturers can’t make that guarantee because there are a lot of factors that affect the economics. Some of these factors will reveal themselves as I crank through two examples of the economics associated with alternative energy sources.
Many factors affect the economics of a particular system. These factors include but are not limited to the climate, the cost of fuel over the life of the system, the cost of the alternative energy systems, the loads and lifestyle of the homeowner, available tax credits and loan interest rates. Many assumptions have been made in the following examples. The assumptions made in the following examples may be very different from those that affect a system for your house in your area. Before you purchase a system, I strongly recommend that you work out the economics of the system you are considering. Some states have tax credits for installation of alternative energy systems. Some systems that might not normally be economical may become economical with these tax credits. Back in the mid-seventies, the Federal Government had a 40 percent tax credit and the state of Delaware had a 20 percent tax credit for the installation of alternative energy sources. Why don’t we have credits like these today?
Gasoline Powered System
Let’s consider the economics of purchasing a stand-alone gasoline-powered generator system to supply all the electric needs for a house for five years. This system would replace the normal utility source. I have chosen a five-year period because I am assuming the life of the generator operating continuously is five years. Let’s assume that the house uses 12,000 kWh of electric energy each year and the maximum demand is 15 kW. The maximum demand is the maximum load that might be on at any time. For this house, the 15 kW maximum demand comes from the assumption that the following appliances could possibly be on at the same time: the air conditioner (6 kW), hot water heater (2.5 kW), oven, one small burner and one large burner of the stove (total 5 kW), TV, clothes washer, some lights and the refrigerator (total 1.5 kW). To be able to operate all these appliances at the same time, we will have to purchase a 15 kW generator. Let’s assume the installed cost of the generator and fuel tank is $20,000. If we obtain a five-year loan from a bank for the $20,000 at 7.5% APR, the monthly payments would be $400. The total expense with interest over the five years will be $24,000.
We assume the insurance on the generator is $380 per year. The generator will run all the time except during maintenance every six months. We will assume the maintenance on the generator will be $5000 over the five years. The generator uses 1 gallon per hour at no load and 2.5 gallons per hour at full load. We estimate that the generator will average about 1.4 gallons per hour or 12,264 gallons per year. If the average cost of gasoline over the five-year period is $3.00 per gallon, the total fuel expense is $183,960.
The total cost is $219,660 over the five-year period (loan plus insurance plus maintenance plus fuel). The generator would have generated 60,000 kWh. The cost of generation would be $219,660 / 60,000 kWh = $3.66 per kWh. If we purchase the energy from the utility, it would cost us about 15 cents per kWh. Obviously, the purchase of this generator is not economical.
Gasoline Hybrid System
Several things killed the project above. The first one was the cost of gasoline. The second one was the size of the generator. The average load for the year was only 1.37 kW but in order to supply electricity at all times, we had to purchase a 15 kW generator. Most of the time, we were not utilizing the capacity of the generator. If we installed a 3 kW generator with deep-cycle batteries to store power for times when the demand exceeds 3 kW and an inverter to convert the low voltage dc power to 120 and 240-volt ac, the economics can be greatly improved. Hybrid cars use the same design. The engines in the hybrid cars are sized a little bit larger than the average power, not the peak power. When the power needs of the car are less than the capacity of the engine/generator, like when the car is not moving, the engine charges the batteries. When the car needs more power than the engine can produce, the batteries assist the engine. The hybrid system costs more up front but the average gasoline consumption drops to 0.5 gallons per hour or 4,380 gallons per year. At $3.00 per gallon, the fuel cost is now only $65,700 over the five years. The energycost is now $101,400 / 60,000 kWh = $1.69 per kWh. It’s getting better, but the cost is still over ten times the utility cost.
Disadvantage of the Hybrid System
When the generator is sized for the peak load, there is always capacity to meet the customer’s needs as long as we do not exceed the peak load for which the system was designed. If we install a hybrid system, there may be times when the system does not have enough capacity to meet the customer’s needs. For example, if we assumed in our design the air conditioner would never be on more than half the time, and an abnormal extended heat spell hits the area and the air conditioner has to stay on more than half the time to keep the house cool, the system may run out of stored capacity.
Solar Powered System
Let’s consider the economics of purchasing a solar powered system to supply all the electric needs for a house for twenty years. Let’s consider a solar voltaic array (solar cells) in combination with deep cycle batteries and an inverter to convert the low voltage dc to 120 and 240-volt ac. In the solar powered system, the solar cells charge up the batteries during daylight hours. The batteries supply the power any time the house uses power. The upfront cost of this system is a lot more than the gasoline generator system but there is no fuel cost. We will consider the economics of this system over a twenty-year period since the life of solar cells is twenty years. To supply the 12,000 kWh of energy each year in a particular solar climate, we will assume we will need 1000 square feet of solar panels. This determination is one best made with the help of the solar panel manufacturer. The cost of the panels is $100,000. We will need forty deep-cycle batteries at a cost of $6,000. During the twenty years, the batteries will have to be replaced every five years. Total battery cost $24,000. The 15 kW inverter will cost about $10,000. If we finance the cost of the panels, batteries and inverter, the monthly payments on a $134,000 loan at 7.14% APR will be about $1,050. Note that you end up paying a little over $252,000 over the life of the loan. Insurance will cost about $2280 per year. We will assume the maintenance cost to be $10,000 over the twenty years. Total cost for the system over the twenty years would be $307,600. The energy cost would be $307,600 / 240,000 kWh = $1.28 per kWh. The cost is cheaper than the gasoline hybrid system but the cost is still almost nine times the present electric utility rates.
In part two, I will get into alternative energy systems that operate in parallel with the electric utility source. In these systems, the goal of the alternative energy source is to reduce the electric bills. Unlike the stand-alone systems described above, the parallel systems can be much more economical.
Read more by David Young
Posted By Michael Weitzel,
Thursday, November 01, 2007
Updated: Saturday, February 09, 2013
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Have you seen an electrical installation that stops you in your tracks? We’re talking about those installations that make you laugh and shake your head in disbelief! Others may make you angry that someone risked his safety and the safety of others. You may want to grab a camera and take a photo in order to share your shock or amazement at such an installation. It can be upsetting to find an installation where the installers knew of the hazards, ignored them, and subjected themselves or others to serious injury or death. Laziness, arrogance, ignorance, pride, unwillingness to purchase or install the proper wiring methods or equipment, or disregard for the safety of others all could enter into what occurred.
Inspectors will no doubt come across many unsafe installations during the course of their career. The question is, How do they deal with it? This article will discuss recognizing hazards, degrees of hazards, inspector training and support from their superiors. The role of public servants will be discussed, along with management styles, liabilities, when to shut the power off immediately, when to write a correction notice and give some time for correction, and other issues.
How do inspectors recognize a hazard? Some hazards are obvious, which even untrained persons would recognize. Some basic examples are:
- Exposed live parts
- Severely damaged conductors or equipment
- Used wrong equipment
- Overloaded circuits
- Weather-damaged electrical wires, poles, or equipment
Photo 2. While inspecting de-energized outdoor units and disconnects, the inspector identified a 110.26 working clearance violation.
Other hazards are not as obvious but could be deadly. An example is an old 1940s vintage 240-volt 30-ampere fused outdoor service disconnect installed on a dwelling unit. The homeowner has called an electrical contractor and complained of no heat from his electric hot water heater, and requested an electrician to come check it out. The switch has a metal handle which operates the knife blades of the disconnect. The insulating material which separates the metal bar and operator handle has broken off and this hazard is not visible to the viewer. On first glance, most electrical professionals and many homeowners would think the handle needed to be moved up into the on position toward the wall of the building, in order to re-energize the circuit. However, to do so would result in a line-to-line fault (short-circuit) at the handle of the service disconnect, because the metal bar that is part of the handle would contact both lines of 240 volts via the fuse blades, which could electrocute the person holding the uninsulated metal handle.
This dangerous situation would require immediate disconnection of electrical power. The necessary repairs—at a minimum—would include replacing the service disconnect, assuring proper overcurrent protection, grounding and bonding of the disconnect, and possibly replacing service-entrance conductors and mast, if needed.
There are many more examples that could have the same fatal result.
The worker should be trained and aware of possible electrical hazards. He must be wearing proper PPE and have tools appropriately rated for the voltage. He must turn off the power to the disconnect and carefully open it to investigate the problem before trying to re-energize the circuit.
It must be remembered that not all code violations are unsafe conditions, but all unsafe conditions are code violations.
Photo 3. Illegal taps of service conductors, damaged service disconnect has inadequate fault current rating. Overfused conductors, neutral and equipment grounding conductors are not properly terminated. Numerous other violations exist.
Have electrical inspectors received training on how to handle unsafe conditions? Do they know what to look for? Do they have a broad range of electrical experience to draw from, or has the bulk or their experience been in another trade, such as plumbing or building? At this point, it is very important to remember NFPA 70E, Standard for Electrical Safety in the Workplace. NEC-2008 draft states that a qualified person is "one who has skills and knowledge related to the construction and operation of the electrical equipment and installations and has received safety training to recognize and avoid the hazards involved.” Do electrical inspectors have the training and experience to recognize electrical hazards to themselves? Do they possess the awareness, safety training and the personal protective equipment needed to avoid the hazard, to protect themselves and others, and to make the right call for the good of all concerned?
Electricity is a wonderful tool when used in a safe and proper manner. If not, it can be a deadly hazard.
Do Electrical Inspectors Have Support?
What kind of backing or support do inspectors have from those in authority over them? Does the inspectors’ supervisor trust their abilities as professionals, have faith in their decisions and ways of working with the customers, and value their judgment?
Who manages or oversees the work of inspectors? Management styles vary. Some code-enforcement managers are truly concerned for public safety, and are willing to address issues and confront persons in a legal and proper manner if there is an unsafe condition. They are willing to do what is right, because it is right, because they genuinely care about safety. They are experienced and knowledgeable electrical professionals. Other managers may not have an electrical background, but do have knowledge and experience in other areas, good common sense, and they work well with electrical inspectors and trust their judgment. This makes for a workable situation and is good for all concerned.
Photo 4. New emergency power system. Ten 1/2? EMT conduits, three phases of 480Y/277-volt circuits installed into a 4? square j-box. Loose wire nuts, conduit connectors and locknuts. Box has no cover and has loose extension rings. Numerous other violation
Other managers or officials may be unaware of, or may not recognize or believe that a safety hazard exists. They may be hesitant to act, or may quickly fold under public or political pressure, or if a customer gets angry or threatening. Perhaps the upset customers are community leaders or government officials that want their work passed, even though it is not up to code. In these cases, complacency and compromise, as well as "enforcement lite” become the name of the game. This can be very challenging for conscientious inspectors. Those who have supportive bosses should appreciate them.
If the inspectors have a boss that is difficult to work for, they should be under his or her authority as best they can without compromising their integrity, and document, document, document. Some inspectors use a stenographer’s spiral-bound notebook. In some jurisdictions, it may be admissible in court, as the notebook cannot be added to, if the records are kept in neat and chronological order without space in-between to add entries. This is only an observation, and would need to be verified by legal professionals in the inspectors’ locality. If inspectors are instructed by their superior to do something that violates their good conscience, they should explain their views respectfully, provide supporting factual data—Code requirements, related photos, and viewpoints of others whom they may value and respect—and respectfully appeal to their authority. Hopefully, the authority will listen. If not, they may assign the task to others or direct inspectors to approve the installation. Someone has to make the decision and, unfortunately, sometimes inspectors will not like the results. The decision rests with those in authority. It is best for inspectors to be under authority, respect their authority, and work with them the best that they can. If the manager, supervisor, or director makes a decision contrary to what the inspectors would like to see happen, the inspectors need to abide by that decision, realizing that the responsibility for the decision no longer rests with them. An article in IAEI News, "The Authority of the Electrical Inspector,” beginning on page 96 of the January/February 2007 issue, addresses these matters in further detail. It’s always wise for inspectors to think about how they will handle these types of situations before they get into them, and to the best of their ability to make the right call regarding the electrical installation.
Evaluating the Installation
When electrical inspectors become aware of an unsafe situation, there are a number of items to consider, such as:
- How bad are the violations? Is there an immediate danger to life or a hazard to property if the power remains on?
- Does the violation upset inspectors because it isn’t right, or doesn’t meeet the letter of the Code?
- Is it a flagrant violation, or one that simply does not meet the letter of the law but is not a real hazard?
- Was it done in ignorance or because the owner or tenant trusted that the installers knew their stuff and would do it right?
In some cases, the owner or tenant may have hired contractors who were unqualified or dishonest and may have paid them already, and now they have limited or no resources available to correct the unsafe situation.
It is always important to keep personalities out of the picture when evaluating work. For example, inspectors should not write more corrections on work just because the electrical contractor is arrogant, non-compliant, argumentative, and generally a pain to work with.
- Are the violations a result of persons who knew it was wrong and did it anyway?
- Or, the result of untrained persons trying to make the situation safe, but not knowing or asking the right people how to do it correctly?
The motive of installers can be important to know, in order to pass judgment on the installation in an appropriate way. Correct those who are in flagrant violation, but don’t be too strict if the work doesn’t warrant it.
- Was part of this installation acceptable under previous editions of locally adopted electrical code?
These questions may seem immaterial, but it is best to know as much as possible before deciding whether to disconnect the power, how much time to allow for corrections, and if other laws such as permitting fees and licensing laws have been violated. For fairness, it helps to try to ascertain the intent of the persons involved before taking action and passing judgment.
Inspectors must always remember that they are dealing with persons, but also the law, and must exercise their authority judiciously and without malice, with electrical safety as the goal; and they must treat others, as they would want to be treated. It is wrong for inspectors to abuse their authority.
- Was an electrical permit(s) purchased for the work?
- Was the customer aware of the safety concerns prior to this? How were they made aware of the concerns? By whom? What have they one, if anything, to address the concerns?
- What is the permit history for the property? When was the last electrical permit purchased? Was the installation part of that permit? Was the work ever inspected? Did the inspector approve the work at that time? Were corrections needed? Were they completed, and was there a call for re-inspection? Were records kept?
- How did inspectors learn of the violations? Was it during a routine or scheduled inspection, or because of concerns with the electrical installation by the fire department, building department, or by inspectors from other disciplines, a contractor, tenant, or other public or private agencies? Should any of the above named departments or individuals be involved? Sometimes a situation that doesn’t look right electrically could be a fire hazard. Other public health or safety issues may be stumbled upon inadvertently.
- Are insurance adjusters involved?
- How extensive is the damage?
- Does the local electrical law require that if more than 50 percent of the structure is remodeled, refurbished, rewired, etc., that the whole installation needs to be brought up to current Code standards?
Inspectors must be able to give code references for every correction written, and be able to explain to the customer or contractor why the correction(s) are needed, and must write the violation/correction notice so that it is easily understood.
- Did an unlicensed contractor perform the work?
- Will the owner reveal who that person or company is?
Electrical inspectors generally take their job and electrical safety seriously, which is a good thing. Unfortunately, not everyone shares that same level of concern for electrical installations. For example, the customer may have a very dangerous installation and not realize just how dangerous it is, even after inspectors give a good explanation.
A sense of humor may help relax inspectors or customers, but only if appropriate. Let’s face it, a lot of "creative wiring” goes on, and some of it is so outrageous that it can be taken as humorous.
- What time of year is it? In the wintertime, in cold climates, shutting off power to a structure —particularly a home—can be serious business.
- Are any of the occupants of the structure on oxygen or life support equipment? If so, it would be unsafe for the power to be disconnected. Is there another place for the occupants to live while repairs are made?
- If a fire situation, how much of the structure was damaged? Could the structure still be lived in if a qualified electrician disconnected the damaged part of the wiring from the power source? Would this be OK, pending the approval of the fire department and electrical inspector?
Making the Call
There are situations, however, where electrical inspectors must make an immediate judgment call on the installation at hand. Is there an electrical hazard to life and property present? Is it an immanent threat—one that is present or inherent, or is it rapidly deteriorating to the point of becoming a serious hazard? Is it time to call the electric utility and wait on-site until they arrive and shut the power off, or is it appropriate to notify the responsible persons in writing of the violations, and leave? Inspectors must contact the owner, and inform them of the hazard. It may be time to contact the owners and give them a limited number of hours or days to make the needed corrections. Either way, a correction notice or citation must be written clearly and contain all pertinent information.
What to Include on the Correction
Notice/Notice of Violation
It is always important to include the following information on the correction notice or citation:
1. All electrical corrections applicable to the unsafe installation. It is essential—this cannot be over-emphasized—and critically important that inspectors be fair but thorough and include all violations on the initial notice of violation. It is unfair and a disservice to the customer for the inspector to write corrections, have the responsible person make all corrections listed on the initial notice, and then return and write more corrections that should have all been listed on the first notice. This is nearly guaranteed to anger and frustrate the customer.
2. Date and time that the citation was written
4. Owner’s, tenant’s, and/or contractor’s information —any and all that apply
5. Telephone numbers of all parties concerned, including inspector’s
6. Party (parties) responsible for the installation or hazard, if known
7. How inspectors came upon the unsafe condition—what duties they were performing when they became aware of the unsafe situation, or if the fire department made them aware of it, etc.
8. What specific code violations exist? Give which code or ordinance, and describe the situation so that even a novice person could understand the hazard.
9. Electrical inspectors’ action; for example, "The serving electric utility was called for an immediate disconnect of all electrical power to the structure,” or something to that effect.
10. State, which, if any, permits or licenses are required to correct the work.
11. If electric power is allowed to remain on at the structure, specify the amount of time the responsible party has to make the corrections and call for a re-inspect.
12. Date that the corrections are required to be completed.
13. Inspectors must clearly communicate orally and in writing that all corrections must be completed as outlined in the notice of violation and that the work must be re-inspected and approved by the AHJ. Examples are before a specified date: electrical power is restored, persons may reoccupy the structure, specified electrical equipment or machinery may be used; or normal functions (business, etc.) related to the electrical system and use of the installation may resume.
If corrections are needed to remedy an unsafe electrical installation, or an immediate electrical hazard exists, the manner and demeanor of inspectors as they approach the customer is very important. The inspector’s body language and tone are both extremely important; remember that over 90 percent of what people receive as communication from us is from our body language, and less than 10 percent of what we communicate is through what we say. If inspectors are professional, knowledgeable, and have good people skills, it will make the unpleasant news a little more bearable: the power may have to be shut off, and/or the customer’s time and money will have to be spent. Most customers have hundreds of ideas of how to spend their money, and very few plan to spend it on their electrical system. Inspectors must effectively explain the hazards involved, the threat to the owners’ safety, and their liability if others are injured by their inaction. Many times a fire marshal or battalion chief, fire captain, electrician or electrical contractor may be present as well, which will add credence to what inspectors are saying, and help customers accept the news. It is a good idea for inspectors to speak with fire or other electrical personnel before they approach customers, and thereby present a more unified front. Inspectors should also be careful how customers perceive their role with an electrical contractor. This is advisable, so that customers do not think the contractor willing to fix the problems is in cahoots with the inspectors, or that inspectors will gain from the contractor monetarily or in other ways.
It pays field inspectors to develop great people skills, and handle difficult customers and situations at their level. This is better than taking a hard-nosed, totally-by-the-book and zero-compromise attitude and becoming difficult for customers to talk to or deal with. Safety is the job of electrical inspectors, most of whom are persons of high integrity, who really care about protecting the public and approving only those electrical installations that they know are safe. They are reasonable people who are trying to do their jobs to the best of their ability. Some inspectors out there are on a power trip or don’t really look at the work in an installation. These inspectors enjoy feeling important, but they do their customers a great disservice. Appearing to be tough and abusing their authority are the only ways they know to do their job. For others, the inspection day is one big social event where they drive around, talk to people, and are paid for it. These inspectors are not doing what they’re paid to do, which is to look at the work, know what they’re looking at (or find out), and assure code-compliance for safety.
Some inspectors make their jobs more difficult than they need to be, simply by being unapproachable and hard-to-talk-to or incompatible. It pays to listen to customers and their viewpoints. Information may be shared that will increase their knowledge, or change their viewpoint of the installation.
It is critical to write corrections when they need to be written, and to be prepared to give a bona fide Code reference for every correction. Inspectors must put themselves in the shoes of the owners, contractors, or installers, and try to understand why the installation was done a certain way. However, things are what they are, and the installation is just plain unsafe, and non-compliant. Fine. Write the correction(s) because it is clearly needed. The installer and/or installation have really earned one. Write it.
Just as important as the ability to recognize electrical hazards, and make others aware of them, is how inspectors follow up and gain compliance with the electrical codes which apply to the particular installation. Writing corrections is good, when appropriate, but carries no weight and has no teeth if there is no follow-through. Violations must be corrected as required in the notice, within the timeframe specified. Be sure that the timeframe is appropriate and reasonable, and that it follows the guidelines in the law or inspection policies. Inspectors must bear in mind that a legitimate extenuating circumstance may arise to delay the corrections of all violations, but the corrections still must be completed in a reasonable time, in order to protect persons and property.
We have discussed the need for training and the awareness of hazards, support for enforcement when inspectors write corrections for unsafe installations, evaluating the installation, and some of the many things to take into consideration. We have also discussed making the call, what to include on a notice of violation, people skills and communication, and follow through. Unsafe conditions do exist, and inspectors will come across them. Remember, inspectors have authority; but how are they using it? Hopefully, this article has provided some food for thought as inspectors approach their task of keeping the public safe from the use of electricity.
Read more by Michael Weitzel
Posted By Underwriters Laboratories,
Thursday, November 01, 2007
Updated: Saturday, February 09, 2013
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Question: Knockouts on panelboards
Are concentric and eccentric knockouts on panelboards Listed for bonding at over 250-volts? How about on outlet boxes?
No. Enclosures for panelboards as well as enclosed switches are evaluated using requirements in the UL Standard for Safety for Enclosures for Electrical Equipment, UL 50. Requirements in UL 50 do not include an evaluation of concentric and/or eccentric (also known as tangential) knockouts for bonding. UL did have requirements in place at one time, which detailed construction, and performance requirements for evaluating concentric and/or eccentric knockouts for this purpose. Subsequent to actions taken by the UL 50 Standards Technical Panel (STP) in 2005, these requirements were withdrawn.
It should be noted that there are enclosed switches in the field, which were manufactured prior to action taken by the UL 50 STP in 2005 that were investigated by UL and marked for this purpose. These enclosed switches were evaluated for the suitability of using the knockouts in the bonding path and continue to be Listed for this purpose. However, subsequent to the 2005 UL 50 effective date, newly manufactured enclosures evaluated using requirements in UL 50 are no longer permitted to be marked indicating the use of concentric and/or eccentric knockouts for bonding purposes.
Concentric and eccentric knockouts on all Listed metallic outlet boxes are Listed for bonding above and below 250 V. Metallic outlet boxes are Listed under the product category Metallic Outlet Boxes (QCIT), located on page 247 of the 2007 UL White Book. The Guide Information for QCIT states: All boxes with concentric or eccentric knockouts have been investigated for bonding and are suitable for bonding without any additional bonding means around concentric (or eccentric) knockouts where used in circuits above or below 250 V, and may be marked as such.
Read more by UL
UL Question Corner
Posted By Underwriters Laboratories,
Thursday, November 01, 2007
Updated: Saturday, February 09, 2013
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Question: CE Mark and NRTL Mark
Is a CE Mark the same as a NRTL mark?
No, a NRTL Mark is the certification mark of a nationally recognized test lab as accredited by the Occupational Health and Safety Administration (OSHA). You can determine which test labs are nationally recognized testing laboratories (NRTLs) as well as the scope of their accreditation (which standards they can certify to as a NRTL) by accessingwww.osha. gov/dts/otpca/nrtl The UL Mark is
the most well known and accepted NRTL Mark.
A CE Marking is a European marking of conformity that indicates that a product complies with the essential requirements of the applicable European Laws or Directives with respect to safety, health, environmental and consumer protection. Generally, this conformity to the applicable directives is done through self-declaration. The CE Marking is required on products in the countries of the European Economic Area (EEA) to facilitate trade between the member countries. The manufacturer or its authorized representative established in the EEA is responsible for affixing the CE Marking to its product. The CE Marking provides a means for a manufacturer to demonstrate that its product complies with a common set of laws required by all of the countries in the EEA to allow free movement of trade within the EEA countries.
Unlike the UL Mark, or other NRTL marks, the CE Marking: 1) is not a safety certification mark, 2) is generally based on self-declaration rather than third party certification, and 3) does not demonstrate compliance to North American safety standards or installation codes. Please keep in mind that a product that bears a CE Marking may also bear a certification mark such as UL’s Listing Mark, however, the CE Marking and the UL Mark have no association. The UL Mark indicates compliance with the applicable safety requirements in effect in North America and is evidence of UL certification, which is accepted by model North American installation codes such as the National Electrical Code and the Canadian Electrical Code.
The CE Marking on products is not a certification mark. AHJs should continue to look for the UL Mark on products in order to determine if a product complies with applicable safety requirements for North America.
For more information on the CE Mark and what it represents, please refer to the CE Marking Information section of the 2007 UL White Book on page 38, or online at UL’s Regulators web site at: http://www.ul.com/regulators/CEmarkinfo.cfm.
Read more by UL
UL Question Corner
Posted By Ron Janikowski,
Saturday, September 01, 2007
Updated: Saturday, February 09, 2013
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Educational facilities now demand a new set of standards for the electrical designer. Colleges, technical schools and even new high schools now require a complex system of networking throughout the classrooms, offices, libraries and administration offices. Higher educational facilities offer classes over the internet or through teleconferencing with outreach campuses. Post 9/11 security issues also add to the mix. A typical data center will see many changes in its IT equipment with the evolution of servers, routers and mass storage devices. With all the information technology equipment required to provide all these services added to the UPS and HVAC systems required, the only logical choice is to provide design for an "Information Technology Equipment Room.”
In 1968, theNational Electrical Coderecognized the unique nature of the data center when it published Article 645, Electronic Computer/Data Processing Equipment. It set out the ground rules for powering, wiring, interconnecting, and grounding mainframe computers in data centers. Many of these rules modified other sections of the NEC. In 1996, Article 645 was re-named Information Technology Equipment.
Computing has changed a lot over the years. Mainframe computers that primarily handled data were replaced with desktop computers and through data closets were networked together. As technology advanced and many other applications were utilizing computer technology, the need for a central ITE area was introduced. Today the mission critical operations for 911 centers, international banking functions, internet functions, fire alarm, security and system control demand a central fire-rated secure room to house this equipment.
Article 645 allows some leniencies
Article 645 in NEC-2005 discusses the requirements for information technology equipment (ITE). It is important to note that NEC chapters 1 through 4 are required for the design of electrical distribution systems. Chapters 5, 6 and 7 are for special conditions that apply to special occupancies and equipment. The rules are optional but if you choose to comply with the special requirements, you are allowed some code leniencies. These spaces typically require a significant number of additional requirements in order to be code-compliant.
An ITE room must meet the following conditions:
- It has an emergency power off (EPO) disconnecting means that complies with 645.10 (which we will address along with NEC-2008 changes in more detail, later).
- It has a separate HVAC system dedicated for information technology equipment or separated from other areas of the occupancy with fire and smoke dampers installed at the point of penetration to the room from common HVAC systems.
- The only equipment installed in the room is listed IT equipment (some exceptions were added in NEC-2008).
- The only occupants are people needed for the maintenance and functional operation of ITE.
- The room is separated from other occupancies by fire-resistant-rated walls, floors and ceilings with protected openings.
- It is an enclosed area specifically designed to comply with the construction and fire protection provisions of NFPA 75, Standard for the Protection of Electronic Computer/Data Processing Equipment. Applicable local building codes also apply.
- Where a raised floor is installed, smoke detectors below the floor must upon activation, automatically cease airflow below the raised floor.
There are two main leniencies granted by Article 645. First, non-plenum-rated cables are permitted below a raised floor. Second, listed IT equipment cables, boxes and the like are not required to be secured in place.
With the numerous IT cables that are required in a modern ITE room, it is obvious that these Code leniencies become major. That, coupled with the frequent interchange of cables and IT equipment, makes it good sense to include an ITE room as part of the building design.
First, install an emergency power off
One of the first and most essential requirements for information technology equipments rooms is the installation of a disconnecting means complying with 645.10. This emergency power off (EPO) is a safety mechanism and must be readily accessible and located at the principal exit doors, and be intended to power down an entire room of IT equipment in an emergency, in order to protect personnel and facilities. EPO can be used either by emergency responders or by equipment operators. Firefighters might use EPO as a quick way to guarantee that emergency responders are not exposed to dangerous voltage, or to eliminate electricity as a source of energy feeding combustion. The EPO must also shut down any HVAC equipment as well as any battery backup UPS systems.
IT managers dread EPO station devices. They see them as single points of failure. Unintentional hard shutdown has been documented to cost thousands of dollars to certain industries not to mention the lost connectivity with students, instructors and management. No such requirement exists for IT equipment installed in rooms compliant with chapters 1 through 4 of the NEC. The NEC-2008 amendment to 645.10(1) that permits zone disconnect means will actually improve safety because it will encourage instead of discourage the use of Article 645. This will give us a reasonable balance of safety and business continuity.
Second, meet certain conditions
Whole-room shutdown will not be required when certain conditions are met.
- Disconnect (EPO) is easily accessible and easily located to shut down the affected area of an IT space.
- Zones or spaces are clearly identified with signage acceptable to the authority having jurisdiction (AHJ).
- Documentation and staff training and procedures are in place.
- An approved method of preventing the spread of smoke beyond the perimeter of the zone or space has been determined.
This new method of zoning areas and selecting the proper EPO devices that prevent unintended use will help to prevent disruption of operations and give IT managers some piece of mind.
The second condition is having a separate HVAC system dedicated for the information technology equipment room. NEC-2002 amended this and allowed the HVAC system to be part of the building system, if fire/smoke dampers were provided at the point of penetration of the room boundary. Activation of underfloor detectors would automatically close the dampers. This amendment eliminated the cost of another complete HVAC system.
The third condition requires that only listed information technology equipment be installed in this room. NEC-2008 will amend this section with exceptions for lighting and controls, communications and monitoring systems for fire alarm, security and water detection, and power wiring for wall-mounted receptacles in accordance with chapters 1–4 of this Code.
The fourth condition is that occupants are people needed for the maintenance and functional operation of ITE. This condition is favorable to management.
The fifth condition is that the room be separated from other occupancies by fire-resistant-rated walls, floors, and ceilings with protected openings. This condition is also very favorable to management. Housing sensitive electronic equipment in fire-rated rooms with limited key card access does provide a sense of security for managers and IT professionals.
ITE rooms make good design
With recent amendments to Article 645, the old negative schools of thought about ITE rooms disappear. Information technology equipment rooms make good design. As educational facilities rely more and more on IT functions, it is imperative that these IT functions be reliable and remain up and running. Many facilities use the internet as the student bulletin board for posting grades, instructor communications and assignments; 24-hour access is demanded and expected. High-speed fiber optics link campus to campus across the county. With the World Wide Web, the world is a much smaller place. Keeping up with current and future technologies relies on our IT functions.
In conclusion, we must keep in mind that if an ITE room is in the building design, it must meet the conditions spelled out in Article 645. This puts additional burden on building inspection officials. It is very difficult to meet all the conditions listed, and the AHJ must be involved at the plan review point. If the project is completed correctly, the IT managers and owners will all benefit from safe, secure, dependable and easily expandable IT functions.
Read more by Ron Janikowski
Posted By Ralph Van Haeren,
Saturday, September 01, 2007
Updated: Saturday, February 09, 2013
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How do you ensure the effective indoctrination and training of new inspectors especially when they are distributed over one million square kilometers (415,000 square miles), and serve a diverse customer base of some 12.5 million people?
That is exactly the challenge the Electrical Safety Authority (ESA), the regulatory inspection agency in Ontario, Canada, faced. To compound matters, the company was also facing an aging employee demographic, at the same time its mandate was growing to include working with local distribution companies to impact safety related to electrical distribution systems, as well as introducing a province-wide electrical contractor licensing system. A study of employee demographics revealed that close to 41 percent of the inspectors could be eligible to retire over the next five years, which would create significant challenges to ESA in maintaining an appropriate level of inspection expertise across the province.
Photo 1. Classroom training was structured to provide a thorough understanding of all aspects of ESA's business.
Figure 1. Inspector Demographics (2007)
Staffing for inspectors had always been driven locally, and was performed on a reactive and somewhat ad-hoc basis. When the need for a new or a replacement inspector was identified, a business case was prepared and if approved, a new employee was hired.
Indoctrination for the new employee was fragmented across the province, with no common standards or processes. Oftentimes, there was no alignment to the overall business objectives or the longer-term strategic direction of the company. The training that did take place was predominantly focused on Code understanding and enforcement. The inspection processes were passed on from the more experienced inspectors on the local team to the new employee; and regularly included local interpretations of a particular business practice, which resulted in inconsistencies from a customer’s perspective. In addition, the general focus was more on production and getting the new employee out into the field rather than on ensuring that a complete indoctrination had taken place. The junior inspector also learned through trial and error on the job sites, sometimes resulting in liability to the ESA when a wrong call was made.
Photo 2. Classroom style training was the foundation
The company realized some two years ago that this method of indoctrination and training was not sustainable, and in fact created a risk to the overall long-term success of the business. As a result, a new approach to both staffing and training was conceived in late 2005 that would allow the business to better prepare itself for the future.
Inspector Training Program
In late 2005, ESA modified its approach to staffing for inspectors. This approach introduced an Inspector Training Program that included an annual campaign to hire inspectors in preparation for upcoming vacancies, business growth, and/or new strategic initiatives that the ESA had embarked upon, and to train them as a group or class.
To support this hiring process, selection criteria for the electrical inspection position were reviewed and modified to reflect the importance of key skills other than technical competency. Increased importance was placed on decision making, customer service orientation, leadership, and the use of judgement and discretion.
Figure 2. Aspects of 12-week training program
These last two elements were absolutely imperative for the company as it was transforming its inspectors from code enforcers to safety ambassadors. With this in mind, the company undertook a benchmarking exercise which included discussions with various police departments regarding how they incorporated the use of discretion and judgement into their recruitment objectives.
In order to ensure that a more consistent assessment of all applicants existed, a pre-screening interview team traveled to key locations across the province and conducted interviews with as many as 300 potential applicants. Those that passed this first hurdle were given a personality assessment test, and were asked to write a three-hour Electrical Code exam.
The above was followed up with a final selection interview, again using a dedicated interview team, but with different membership from the pre-screening team, and resulted in a class size of approximately 20 successful applicants.
Photo 3. Hands-on examination of the equipment added knowledge
The 12-week training program that had been developed was designed to introduce new hires to all aspects of the inspection job, and to provide them with background and practical skills to deliver a level of service required by a safety agency. Training design combined both classroom style training along with five one-week field training assignments where the new employees were exposed to the various inspection functions across the business such as residential, commercial and industrial wiring inspection, high-voltage and low-voltage plan reviews, product approval, and ESA’s safety programs. All field assignments were followed up with a developmental assessment, and trainees were expected to deliver a short presentation upon their return. This not only gave them an opportunity to learn how to utilize presentation computer software, but also developed their confidence levels in public speaking.
The classroom training was structured to provide a thorough understanding of all aspects of the Electrical Safety Authority’s business. The safety component incorporated mandatory H&S training such as emergency first-aid, fall protection, electrical awareness, and confined space entry to name a few.
Since all the electrical inspectors work remotely, without the need to report to a physical office each day in order to receive work assignments, the computer training detailed how these work assignments were sent to field inspectors, how the work needed to be processed, and how they were expected to use the work management software. This approach allowed for the full review of the software functionality and its application.
Photo 4. Pre-screening and a final selection interview resulted in a class size of approximately 20 successful candidates
The technical training thoroughly reviewed all major sections of the Electrical Safety Code, and included field trips to review actual installations. The customer and business process training was developed to ensure that every new inspector had an understanding of the internal business processes, and how they should be utilized.
A lot of time was also spent dealing with how to provide excellent customer service, even though the business operates as a regulated monopoly. This training focused on treating customers with dignity and respect, how to handle difficult situations, precautions to take when entering certain establishments, and the need to keep records and notes of customer transactions. Inspector trainees also spent time at the ESA’s centralized Customer Service Centre where they listened in on customer calls, and how the customer service representatives dealt with each customer issue and service request.
All levels of senior management including the president and CEO were committed to the training and provided overviews of their function in the context of the strategic direction of the company and its longer-term business objectives.
At the completion of the 12-week program, the new inspectors were assigned across the province to begin their new career. After a period of approximately 4 to 6 weeks, a job coach or mentor was assigned to ride along with the inspectors. This concept was also implemented as a result from the benchmarking exercise with the police, and made sure that what had been taught as part of the formal classroom training was being put to correct use once the inspectors were in the field. The job coach in ESA’s case was a respected and retired senior inspector that spent time with each of the newly graduated inspectors, and coached them further on how to put their academic training to practical use.
Results and Benefits
The Inspector Training Program has been in place for two years now, and has turned out some thirty-eight newly trained inspectors. The benefits of the program are evident everywhere, within and outside the company. Requests to assist with the future delivery of training for new trainees have been received from ESA staff across the province. The latest class included participation from seventeen experienced inspectors who wanted to volunteer their time and effort to be part of this program, and to deliver a specific element of the training. The new inspectors are now more aligned with the company’s long-term business objectives. Customers have provided feedback associated with improvements on the consistency of interpreting the Electrical Safety rules and their application. It has also enhanced management/employee relations since there has been a demonstrable commitment by management to invest in the training and development of new staff.
The centralization and documentation of this hiring and training initiative has significantly improved the overall effectiveness of the business. New inspectors are more confident of their abilities, have a better understanding of customer needs and the organization’s mandate and direction, and have a clearer understanding of what is expected of them. Looking ahead, this training could form the basis for an inspector certification or accreditation program, and will be expanded to include existing inspectors who did not have access to this training when they were initially hired.
Moving from a reactive and somewhat ad-hoc set of locally developed hiring practices to one that is more proactive and management driven has allowed ESA to begin developing a strategy for dealing with upcoming retirements while at the same time improving the overall caliber of electrical inspectors throughout the province of Ontario.
Read more by Ralph Van Haeren
Posted By David Shapiro,
Saturday, September 01, 2007
Updated: Saturday, February 09, 2013
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Until the mid-1980s, Maryland and DC people had to travel to Baltimore to find regular meetings. We were welcomed by the Chesapeake Chapter, but the trip deterred some. Art Hesse removed this obstacle by resurrecting the George Washington Chapter.
Everyone who knows Art sees his helpfulness: "He’s one of the good ones,” a contractor volunteered. You also see his intelligence and love of learning. He’ll share a "Ya know, Dave . . .” in the certainty that you would enjoy learning some choice fact just as much as he did. Or there’s his appreciation for the information he gets from seminars, even seminars on subjects he himself could have taught. They almost always provide something.
There’s history behind this. Arthur W. Hesse was born in a small town in Wisconsin. His father was a good-hearted carpenter who died helping a neighbor try to save his barn. His mother, grade school educated, taught her sons to value learning.
Art learned early to be hardworking—after his father died, when he was eight or nine, he and his brothers took on every odd job they could, to cope.
Art wasn’t at the University of Wisconsin a year when he volunteered for the Army Air Corps, enlisting to become—who’d have guessed?—a meteorologist.
The Air Force sent him to Reed College for meteorology, to Yale for electronic systems, then to the Air Force Institute of Technology for a BSEE equivalent. After he aced the course, they turned around and had him teach. He won his MSEE (and P.E.) at Stanford, earning top grades.
At his first station, a remote air base in Alaska with a stand-alone generation and distribution system, he developed an interest in power wiring. However, for twenty years he served as a staff engineer at various bases and the Pentagon, handling various aspects of management, from politics to logistics. He ran satellite communication research, headed the Air Force’s electronic countermeasures development program—even completed a tour at ARPA, the Advanced Research Projects Agency (a.k.a. DARPA).
The mild-spoken colonel retired on January 1, 1975, after thirty-three years of service. Prince Georges County, Maryland, was advertising for a chief electrical inspector, and he applied. The head of the building department was excited to have Art for the job. He gained his staff’s support quickly, and they gladly gave this low-voltage engineer the benefit of their experience as electricians.
Art enjoyed his twenty years with Prince Georges County, experiencing the utmost respect from the electrical contractors, with just three or four exceptions. When problems were brought to him, Art managed to sort things out equitably, whether permits needed untangling or contractors needed someone who could resolve Code issues calmly.
Then the political climate changed. Over Art’s protest, the decision-makers chose to economize, first by turning residential inspection over to multi-hats and then by closing down the commercial electrical inspection department and having third-party inspectors take over. Art decided it was time to retire.
However, the mayor of Laurel, Maryland, drafted him: "Just set up an electrical inspection program. Please, we’ll find people to do the work.” For the next decade, Art inspected Laurel’s wiring. At this point in his career, he certainly didn’t need the money. He did it because he enjoyed the people. Even though he doesn’t live in Laurel, Art felt like a member of a big family up there.
In late 2006, though, he developed cancer. They thought they nailed all the malignancy with a combination of surgery and radiation, but it was not so. Recently, Art learned that he has leukemia. His wife drives him for cell transfusions, and he persists, but he will not survive this.
Art Hesse will leave an enviable legacy, both in his son and grandchildren, and in the effects he has had on the electrical community of Maryland and the greater D.C. area. He was a likable leader who made people want to cooperate in doing things right.
Read more by David Shapiro
Posted By John Wilmes,
Saturday, September 01, 2007
Updated: Saturday, February 09, 2013
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According to the United States Geological Survey, the average American uses about 100 gallons of water each day. This, in turn, creates more than 31 billion gallons of wastewater, which is cleaned and recycled by wastewater treatment plants across the country. Under the Homeland Security Act, wastewater facilities play a critical role in the needs of communities; ensuring wastewater is properly treated, especially in emergency situations.
With 450 miles of sanitary sewer-collection lines and 33 lift stations that feed into a central wastewater treatment plant, the city of Lawrence, Kansas, wastewater management system is extensive. The city has been recognized as one of only two in the nation that have three environmental management certifications for wastewater operations. These certifications demonstrate the city’s ability to provide customers with an efficient level of service, while maintaining a high standard of environmental protection.
Photo 1. Ultra-low harmonic drives feature bypass valve, fuse disconnect, remote I-O and selector switches.
Increasing Demand Brings Need for Retrofit
Gravity is the driving force for wastewater distribution to the treatment plant, except where there are vertical elevation changes in the topography. In these circumstances, lift stations—structures that contain pumps and controls—are used to move wastewater to the treatment plant.
Because of ongoing increases in demand, Dave King, wastewater maintenance manager, city of Lawrence, is continually looking for ways to improve efficiency. He explains that lift station number 16, built in 1958 and located close to downtown Lawrence, is responsible for transporting approximately 600 million gallons of dry weather-flow a year, about 25–30 percent of the city’s wastewater usage. The combination of aging equipment and increasing flow from new residential developments led to the decision to retrofit the station completely in the spring of 2006. King turned to the city’s long-time PLC supplier, Logic, Inc. to help develop a solution.
Photo 2. Test instruments (CTs and metering equipment) being connected after the equipment is deenergized and placed in an electrically safe work condition conforming to NFPA 70E.
Logic recommended installing ACS800 drives on each of four new 125-hp pump motors to increase efficiency and power factor to improve electricity cost savings; to extend the life of the motors and reduce repair costs; and to minimize or eliminate an addition of harmonics that can interfere with instrumentation and overheat feeder breakers and transformers.
Drives Ensure Constant Flow
Photo 3. ABB ACS800 drives power pump at lift station. One remains on standby.
When wastewater enters a lift station, it initially goes through a coarse screening process, which removes solid particles that might cause damage to the pumps. The wastewater then flows into an enclosed wet well, which can be 30–40 feet deep. Sensors monitor the depth of the wastewater in the wet well. Pumps are used to displace the wastewater from the well to the treatment facility. Drives often play a key role in supporting the pump operation, ensuring that a constant flow is discharged to maintain optimum wastewater levels.
"By controlling pump speed, an optimum level can be maintained that ensures constant flow between what’s coming in and what needs to be pumped out,” says King. "Installing the ABB drives has enabled us to eliminate unnecessary pump starts.”
From Across-the-Line Starter and Constant Speed to Variable-Speed Control
Previously, the site ran the pumps based on an on/off level, and used an across-the-line starter. When the level in the wet well reached a designated point, it would trigger the starter to get the pump motors up to maximum speed as quickly as possible. This rapid acceleration created spikes and mechanical stress on both the motor and pump. It would run at full speed until it reached the "off” level elevation—and then it would turn off. The constant-speed, starting-and-stopping process caused wear and tear on the bearings and impellers, causing the motors to deteriorate.
Prevent Water Hammers
Photo 4. Close-up of operation panel of power pump
By maintaining a consistent level in the lift station wet well, drives also help to avoid water hammers. When a pump starts or stops suddenly, it slams the check value on the back of the pump and creates a water hammer effect. Water hammers are pressure surges caused by the energy of a fluid in motion when it is forced to stop suddenly. In plumbing, this is experienced as a loud banging noise that sounds like a hammer hitting the pipes. The shock wave causes pipes to rattle and shake violently.
In a lift station, hydraulic water hammers often occur when trying to pump fluid vertically or at a slant. Once a pump stops, the fluid will come back to the source, jarring the piping. Over time, water hammers can lead to pipe deterioration. Because the ACS800 drives provide acceleration and de-acceleration ramp to the pumps, wear and tear on the pump mechanicals are reduced.
Keep Drive at the Ready; Balance Usage on Others
Photo 5. Interior of the pumping station
Drives also incorporate a soft-start function that gently ramps speed to limit potential turbulence—and reduce the need for maintenance. The drives respond to sensors in the wet well that are relayed to a PLC unit via DeviceNet. The wastewater treatment plant communicates with the PLC unit at the lift station via Ethernet to ensure that wastewater levels are being pumped out consistently, based on established parameters. Although three pumps are needed to run the station, the city keeps an installed fourth pump on stand-by at all times, running them alternately to balance wear on them. The station operates 24-hours a day and cannot afford downtime.
"ABB drives give us the ability to handle the wide range of variations in wastewater flow entering the station due to time of day, time of year and weather conditions, as well as the capacity to accommodate future growth,” says King. "The fact that we can now pump wastewater out at the same rate it enters also helps us reduce odors.”
By-Pass Feature Important for Constant Uptime
Since wastewater is constantly running throughout the city, another important feature to the lift station is the by-pass function, which allows a manual override of the pump if a drive were to go offline.
"Even though modern drives are very reliable, if for any reason we were to have multiple drive failures, the bypass gives us the ability to still operate the station,” explains King. "At this location, station down-time is not an option.”
Ultra-Low Harmonic Drives Provide Protection to Power Grids
Because the lift station is located next to a residential district, minimizing harmonic distortion is a necessity. With the amount of dynamic load on the existing transformer, standard drives were not a viable option. "Excessive harmonics can interfere with pump instrumentation,” King says. "Plus, we didn’t want to cause any interruption to the electrical appliances of our customers.”
Ultra-low harmonic drives do not require a multi-pulse transformer, external filters or other additional equipment for minimizing harmonics. The drive features an active converter with direct torque control (DTC) to eliminate low-order harmonics. With an active front-end LCL (Inductor, Capacitor, Inductor) line filter to reduce high frequency harmonics, the city did not have to worry about overheating feeder breakers or transformers.
Drives Offer Turnkey Solutions – Easy Installation
King was impressed with ABB because of its ability to offer turnkey solutions direct from the factory. "We required certain features in the cabinet, such as a by-pass, fuse disconnect, remote I/O and selector switches. ABB was able to provide all that from a factory service center,” he says. Since the lift station fits in a 900-square-foot space, the ACS800’s compact footprint fit well into the facility.
Since the drives were shipped with all of the specifications pre-installed, installation was a smooth and easy process. To maintain constant uptime during the retrofit, two pumps were taken off-line at a time, keeping the other two pumps running.
Results Foster Continued Relationship
The lift station retrofit was not the first instance where the city has benefited from using these drives. The wastewater treatment facility also has ABB drives equipped with bypass to increase efficiency. Because of the positive experience with the drives at lift station number 16, the city is installing drives in four other wastewater pump stations now under construction.
King concludes, "I really appreciate the technical assistance and customer service we have received. I anticipate extended pump life, electric cost savings, and ultimately better service to our customers as a result of the drives.”
Read more by John Wilmes
Posted By Alan Manche,
Saturday, September 01, 2007
Updated: Saturday, February 09, 2013
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Just like clockwork, the 2008 edition of theNational Electrical Codeis now available, which always brings a plethora of education and materials on the changes taking place in the NEC. Understanding the changes is important to electrical inspectors in order to understand the safety or enforceability enhancements that have been made to support an electrical installation.
Let’s take a brief look into the future and explore a few of the new items one will find when inspecting to the 2008NEC.
Let’s peer into a home that has been wired in accordance with the 2008 NEC. One of the first recognizable differences will be the tamper-resistant receptacles located throughout the home. NEC 406.11 requires that all 125-V, 15- and 20-A receptacles of the home installed in accordance with NEC 210.52 be tamper-resistant. These new receptacles will provide needed protection from children inserting narrow metal objects into a single slot of the receptacle, which can create a shock or burn hazard.
Before progressing through the rest of the home, it is a good idea to proceed directly to the garage, basement or other service location to locate the load center, in order to understand if the electrical contractor has been wiring to the 2008 NEC. Upon arriving at the load center, one will notice a number of differences—a much longer panel that has more than 50 circuits installed; more AFCI circuit breakers than before with different-colored test buttons; an automatic transfer switch as part of the service panel, along with a controller that appears to automatically control loads; and finally, surge protection with a Type 2 designation. At this point, an electrical inspector might be thinking, "Is this a fancy house with all the bells and whistles or did I miss a few things during all those code education classes?”
The panel with 54 circuits is obviously the answer by the electrical equipment manufacturers to support customers with more circuits in a panel and is based on the elimination of the 42-circuit limitation in Article 408. One caution in looking at this type of installation is that the panel still has to be listed for the number of circuits installed. Read the label to make sure that the installer did not take a normal 42-circuit panel and make some tandem or ½ breakers "fit” into the existing space. The panel labeling will indicate how many circuits can be legitimately installed. Do not forget to check the listing of the cable clamps used to attach the NM cables to the enclosure; it may be that with all those additional circuits, the contractor has doubled up and even tripled up on NM cables in the cable clamps. There is a good possibility a violation exists where more than two cables are in a clamp. However, if the clamp is evaluated for more than two cables, the tripled up versions may be acceptable.
It appears the number of AFCIs have doubled in this panel as compared to a similar size home. NEC 210.12 has expanded the requirement for combination AFCIs to protect additional circuits in most of the rooms that are found in NEC 210.52(A)—those rooms that are required to have receptacle spacing around the room, along with closets and hallways. The change in test button color also is explained by the change from the branch feeder AFCI to combination AFCI. You may recall the combination AFCI requirements will go into effect January 1, 2008, based on an effective date that was in NEC-2005. The test button color is one method that manufacturers are using to support easier inspection.
The integrated automatic transfer equipment in this panelboard could raise some questions. These innovations are once again driven by a 2008 NEC change based on concerns expressed by the electrical inspection community. NEC 702.5 requires adequate capacity from the alternate source of power. The issue resides when an automatic transfer places a load on the source that it cannot support. NEC 702.5(2) has been added in order to require the generator to carry the entire load or it requires that a load management means be put in place to limit the load. The controller within this panel is likely serving the load management function to support the revised language in NEC 702.5.
There is no "TVSS” or "Surge Arrester” marking on a Type 2 surge protection device. Similar to the popular move from the terminology fixture to luminaire, the surge protection industry has revised the terms in NEC Article 285 from TVSS to SPD or surge protection device. The type rating establishes where it can be installed. Type 2 is permitted on the load side of the service disconnect, similar to TVSS. A Type 1 device would be permitted on the line side of the service disconnect similar to secondary surge arresters. Finally, a Type 3 device must have 30 feet of conductor between it and the service panel. The bottom line is that a Type 2 SPD is acceptable in this installation because it is installed on the load side of the service disconnect at the service panel.
The more an inspector looks around a home the more changes he will likely recognize. For instance, there may be no dedicated receptacle outlets for appliances in the garage or basement. These additional GFCI-protected receptacles are a result of the exceptions being removed from the NEC 210.8(A). Since the exceptions were about 20 years old, it looks like the code panel has finally eliminated them and caught this section up with the modern UL listed appliance requirements that have leakage limitation. That certainly makes the installation easier to inspect.
Moving outside, an inspector is reminded that receptacles in a damp or wet location are required to be listed as weather-resistant in accordance with NEC 406.8. If a house also has a deck on the back, an inspector will want to verify the contractor understood the new requirement in 210.52(E)(3) that there be a receptacle installed within the perimeter of the deck. This receptacle cannot be used to meet the requirements for a receptacle installed in the back of the house unless it is accessible while standing at grade level. The inspector may find a pool around back, the requirements that surround grounding, bonding and the equipotential plane are far too much to discuss in this venue. The one revision that is worth noting is that hard-wired pool pump motors are now required to be GFCI-protected in accordance withNEC680.22(B).
There are also a number of changes in the 2008NECthat impact electrical installation in commercial and industrial buildings. For example, entering the rear of a mall, one may see a 4,000 A electrical service, with panic hardware installed on a couple of doors that are the entrances to the area where the equipment is installed, but not doors that are in the working space. NEC 110.26(C)(3) has introduced the requirement for panic hardware on doors within 25 feet of the working space.
Just across the hall is a door that leads to a janitorial closet with a sink. The sink has a disposal installed that is plugged into a receptacle under the sink.NEC210.8(B)(5) now requires GFCI protection of 125-V, 15- and 20-A receptacles within 6 feet of sink. The requirement related to outdoor receptacles in other than dwelling locations was also expanded. GFCI protection is now required for all outdoor 125-V, 15- and 20-A receptacles regardless of whether they are accessible by the public, so an inspector might find a few receptacles for holiday decorations or receptacles behind fences that have been missed by the installer regarding this requirement.
The conduit running across the roof may remind an inspector of the ampacity derating that is now required in NEC 310.15(B)(2)(c) for conduits exposed to sunlight. The derating is based on the distance of the conduit from the roof. An inspector must check conductor sizes in the air unit and understand the load placed on them to inspect for the correct wire size after derating.
In looking at the lighting panelboards, an inspector might notice that the designer utilized a number of multiwire branch circuits, using a common neutral conductor for two or sometimes three lighting circuits. NEC 210.4(B) now requires that all multiwire branch circuits have a common disconnect that will open all the ungrounded conductors of the circuit. This will mean that either two- or three-pole circuit breakers will be needed or handle ties could be used with two single-pole breakers. Also NEC 210.4(D) now requires that the multiwire branch-circuit conductors (grounded and ungrounded) be grouped in at least one location within the panelboard. This allows for easy identification of which grounded conductor goes with which ungrounded conductors. There is no wire tie or grouping means found in these panels.
The 2008 NEC introduces a significant number of changes that enhance safety for property and people in both residential and commercial/industrial environments. Electrical safety is an expectation of the citizens of this country and the 2008 NEC delivers on that expectation of enhancing safety through technology and enhancements based on a better understanding from industry representatives that bring knowledge and experiences of potential hazards from electrical installations. Electrical inspectors play a key roll in developing the NEC, driving uniform enforcement and ensuring the safety of every community.
About Alan Manche: Alan Manche is the director, industry standards for Square D/Schneider Electric. He is a licensed professional engineer in the state of Kentucky. He is a former member of NEC Code-Making Panel 8 and served as a member of NEC Code-Making Panels 10 and 20 during the development of the 2008 NEC. He also serves on the technical committee for NFPA 70B - Electrical Equipment Maintenance, NFPA 110 - Emergency and Standby Power Systems, and numerous UL product standard STPs. He has served as a product design engineer with responsibility for product certification of numerous Square D product lines including panelboards, switches, and busway. Alan also serves as a Schneider Electric liaison to the electrical inspection community, providing NEC educational programs across the country for inspectors and contractors.
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