Safety first

CSE: Whose responsibility is it to ensure that equipment such as control panels, lighting panels, or panelboards are properly labeled? Designer, contractor, or the building owner/operator? Lanny Floyd: NEC110.16 is specific that the equipment is “field marked” as opposed to the label being applied by the manufacturer.

04/01/2010


       

       

      CSE: Whose responsibility is it to ensure that equipment such as control panels, lighting panels, or panelboards are properly labeled? Designer, contractor, or the building owner/operator?

       

      Lanny Floyd : NEC110.16 is specific that the equipment is “field marked” as opposed to the label being applied by the manufacturer. The reason for this is the arc flash potential for any given piece of equipment is dependent on upstream circuit parameters beyond the control of the equipment manufacturer. The owner/operator has the responsibility to assess, identify, and mitigate hazards in its facility in order to create a safe working environment. There is also reference to NFPA 70E for analysis methods.

       

      The power systems analysis to quantify the existence and severity of the arc hazard is an engineering study. The owner/operator may choose to include the arc flash hazard analysis in the design package and include application of the labels in the construction package.

       

      Bruce Young : It should be a team effort to ensure that all electrical equipment is properly labeled. The design professional should always specify that an arc flash study be performed and that the labels are installed. But it is ultimately the owner's responsibility.

       

      Stephen Wiggins : I agree, it should be a team effort: the engineer should specify the work properly, the contractor should label the panels as he performs a point-to-point check out of each circuit, and the commissioning authority should verify the entire effort at each level of the project as the owner's representative.

       

      If the project is not commissioned, then the owner should have qualified staff to perform the tests and verification of the effort.

       

      Don Talka : All parties share the responsibility of ensuring that products are suitable for the intended use, and properly labeled for that use. However, the ultimate responsibility for equipment placed into a building falls to the building owner/operator.

       

      CSE: With regard to grounding and bonding, what extra considerations must be observed when designing systems in or for hazardous locations?

       

      Floyd : Locations with potentially flammable or explosive environments must address the ignition potential from two sources of electric sparks—electrostatic discharges and arcing from loose connections in ground fault return paths. Generation of static electricity is inherent in many manufacturing and material handling processes.

       

      Properly designed, installed, and maintained grounding and bonding serves to prevent static electricity accumulation, as well as discharging charge accumulation without sparking. Fault current can take many parallel paths involving dedicated ground conductors, as well as conductive enclosure, structural steel, and piping systems.

       

      Any poor or loose connection in the fault current return paths can create arcs during fault conditions. As with bonding and grounding to control static electricity, the quality of bonding and grounding in fault return paths depends on proper design, installation, and maintenance.

       

      Talka : Two significant instances in the National Electrical Code (NFPA 70) where the requirements for grounding and bonding in a hazardous location exceed those for an unclassified location are:

       

      • Bonding of all metal parts of equipment, raceways, and enclosures is required regardless of the voltage of the electrical system. See 250.100.

      • The locknut-bushing and double-locknut types of contacts are not permitted for bonding purposes.

      For example, see 501.30(A). This also applies to any associated apparatus in an unclassified location that is relied upon to limit energy to intrinsically safe circuits located in the hazardous location. See 504.60(B).

       

      Wiggins : I find this question to be very interesting because I believe that grounding and bonding for all systems is the most overlooked and least valued. The vast majority of system problems in a facility's life can be traced back to poor grounding and bonding systems. As a retrocommissioning engineer I have found that poorly designed and installed grounding and bonding systems are the most common source of facility issues.

       

      Rarely are grounding systems maintained and tested as required. The same level of consideration should be given to every grounding and bonding system if that system is to perform correctly. Many times we overlook this key aspect of our electrical systems because they are neither critical nor hazardous in nature.

       

      CSE: What are the electrical safety considerations unique to specific building types? Which building types present the largest problems?

       

      Young : Healthcare facilities have different distribution system requirements (general, critical, essential, and life safety), which present challenges—ensuring that all circuits are safe, verifying that only the circuit that is being maintained is off, and even scheduling time to maintain the circuit. It is tempting to perform hot work in these environments, which leads to a potentially dangerous situation.

       

      Mission critical facilities (especially data centers) present special circumstances that can lead to problems. Downtime is extremely rare in these facilities, so the temptation to perform hot work is very great. For example, when a new cabinet just needs a new 30-A whip, but we just cannot schedule any downtime, the temptation may be to install the whip hot.

       

      Wiggins : I find that lower-level critical facilities are challenging due to the items I discussed previously. Many times electrical systems for Tier I and Tier II type of facilities are not designed to have parallel paths, but the occupants do not understand that these systems must be shut down for maintenance. If a system cannot be shut down for maintenance, we must design dual paths for maintenance. I know the first thing that comes to many minds will be, “We can't afford to do that.” What we should be thinking initially is we cannot afford to not do this.

       

      Talka : The fundamental electrical safety considerations for buildings are grounding, bonding, overcurrent protection, and the proper selection of appropriate wiring method. Specific building occupancies including healthcare facilities, gasoline stations, theaters, etc., are covered in Chapter 5 of NFPA 70.

       

      Buildings with the most complicated electrical distribution system will always present the largest challenge. NFPA installation codes contain specific electrical system requirements to address complicated and challenging distribution systems.

       

      CSE: To what degree are counterfeit products a problem in industrial electrical systems? How do you protect against this problem?

       

      Young : Electrical devices (breakers, fuses, switches) have to operate reliably under fault conditions and are tested and certified to ensure they will function correctly. Counterfeit products may appear to be identical to the real item—they have the correct labels and physical characteristics—but they are not as robust or reliable as the specified item and will fail when needed the most, which could produce catastrophic results. We require independent testing of larger protective devices after installation. This not only verifies proper settings, but also that the device does operate correctly.

       

      Talka : UL has not encountered counterfeit UL Certification Marks on industrial electric systems. However, we have experience with counterfeit component products that may be used in final applications (wire and cable, switches, etc.). UL works closely with customs agencies to interdict and seize goods bearing counterfeit UL Marks. Additionally, UL undertakes proactive certification mark enforcement activities in product categories where counterfeiting has been determined to be a threat.

       

      Floyd : It is a growing problem. Both the National Electrical Manufacturers Assn. and Electrical Safety Foundation International have education, awareness, and action campaigns addressing this issue. Both organizations' Web sites offer suggestions on protecting consumers and industrial/commercial users from potential hazards of counterfeit electrical products.

       

      Wiggins : As everyone in the electrical field knows, this is a major problem. As a commissioning engineer, I believe this issue speaks to the criticality of proper submittal review and site visit checks. Every piece of electrical equipment should be checked by the owner's commissioning team to verify that it is genuine and as specified.

       

      CSE: What changes to the NFPA 70E and safety-related provisions of the NEC are being debated in advance of the release of the NFPA 2010 meeting?

       

      Floyd : NFPA received more than 500 proposals for changes to NFPA 70E. In its first meeting to address these proposals, the 70E Technical Committee rejected approximately 40% and accepted part or all of 60%. These changes are enhancements, refinements, or clarification of the current requirements and do not encompass major shifts or expansions.

       

      I suspect many readers became aware of NFPA70E through publicity of measures to protect workers from arc flash hazards. NFPA70E is about electrical safety, which includes the more lethal hazard of electric shock.

       

      According to NIOSH analysis of workplace electrical injuries and fatalities, the vast majority of fatal injuries from electrical hazards are attributed to direct contact, or electric shock exposure. If arc flash got your attention to NFPA70E, I urge readers to not overlook the requirements for preventing electric shock injuries or underestimate awareness of knowledge of state-of-the-art practices to prevent electric shock injuries.

       

      Talka : The proposed changes include:

       

      • NFPA 70E—A proposal was accepted that would not exempt circuits rated 240 V or less when supplied by a transformer rated less than 125 kVA from the required arc flash hazard analysis.

      • NFPA 70 (NEC)—A proposal was accepted to require generators used in temporary installations to have integral ground fault circuit interrupter protection. A similar proposal for all portable generators (Article 445) is being debated.

      • A proposal to allow the use of outlet type arc fault circuit interrupter in specific installations is being debated.

      • A proposal requiring air conditioning equipment to contain an equipment-grounding conductor in accordance with 250.118(1); a change that would require redundant grounding in many installations is also being debated.

      Young : It should be recognized that it is possible, with proper training and protective equipment, to perform some work on energized equipment. There should also be a requirement that arc flash studies be updated regularly and labels should include the dates of those studies.

       

      CSE: Explain the process of third-party certification from an end-user perspective. What are the benefits, downsides, and potential complications of such certification?

       

      Wiggins : As a member of a certification organization, I have strong opinions regarding this issue. Certification, if properly applied, provides an end user with confidence in the qualifications of a service provider. However, to bring a slant to the question, I believe any organization that certifies individuals in a discipline must also have a clear and proven policy regarding de-certification. If an organization does not police its members regarding their standards, then that certification is useless and damaging to the industry.

       

      A certification must also require a technical application of the industry expert's knowledge to be valuable to an owner. Cheap certification does not benefit the industry nor does it encourage owners to embrace the requirement for certification. A requirement in the industry for providers to be certified by a quality organization is capable of reducing the percentage of underperforming firms through positive re-enforcement.

       

      Talka : Third-party certifications provide the end user with the assurance that product evaluations are made under standard conditions, to a documented product standard, and that the product is inspected during production to verify continued compliance with the safety standard.

       

      Achieving third-party certification assists with supply chain management and avoids the necessity for repetitive examinations by multiple examining agencies, resulting in unneeded additional expense and loss of time to the product manufacturer. The benefits to regulators, manufacturers, end users, and the public are the assurance of a safe product that also complies with the applicable installation code.

       

      CSE: Due to the large coalition of national and international regulating bodies, how the can process of developing and implementing electrical safety standards be improved?

       

      Talka : Increasingly, manufacturers are designing products for installation in international markets with differing distribution systems. Third-party certifiers, like UL, work with regulators, manufacturers, and end-product users to develop international safety standards to address the safety concerns, and installation requirements of geographic regions and those of specific countries.

       

      UL actively develops standards in concert with Consejo de Armonización de Normas Electrotecnicas de las Naciones de las Americas (Council for Harmonization of Electrotechnical Standards of the Nations of the Americas) and the International Electrotechnical Commission, and is an active member of the international Committee of Testing Laboratories. The active, objective, and scientific-based participation of standards development organizations in the international development process will help to create and improve the usability of international standards.

       

      Floyd : Electrical safety is highly regulated in every industrialized country. Although the hazards of electric shock and arc flash are independent of geographic location, the codes, standards, and regulations in different countries have evolved along different paths.

       

      In comparing North American and European standards, North American standards tend to focus on safe work practices and PPE. European standards tend to put more emphasis on engineering solutions to eliminate or reduce risk of injury. For example, the current scope of NFPA 70E primarily addresses administrative controls such as safe work practices and PPE and does not address engineering design methods to mitigate electrical hazards.

       

      Although there are differences in how to mitigate the hazards, the objectives of electrical safety standards around the world to protect the safety of people and property are the same. By investigating and learning from different approaches, those of us involved in codes and standards development will find opportunities to advance the ongoing evolution in development and application of a more comprehensive approach to electrical hazards control that incorporates engineering design solutions, administrative controls, and PPE.

       

       

       



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