Maintain Your Equipment; Reduce Your Risk, Part 3 of 6
Dave Smith has been an Industrial Maintenance Electrician since 1975. He has taught maintenance, troubleshooting and safety courses to thousands of electricians in mines, mills, refineries, factories, plants, power stations and offshore platforms throughout North America and the Middle East. Dave is a hands-on guy and teache...
In my last article, I introduced you to three excellent IEEE standards that are essential for managing an electrical system. Moving to the next stage in the development of your electrical maintenance program will require more detail, and a stellar source is NFPA 70B, “Recommended Practice for Electrical Equipment Maintenance”.
Chapter 4 “Why an Effective EPM Program Pays Dividends”, Chapter 5 “What is an Effective EPM Program?” and Chapter 6 “Planning and Developing an EPM Program” are valuable, as they provide framework and support to the economic argument of the IEEE standards, as does Chapter 7 “Personal Safety”.
While both NFPA 70B and the IEEE documents are written descriptively, 70B is more pertinent on the equipment level. For instance, clause 6.3.6 speaks directly to alarms:
… Like shutdown devices, alarms fall into at least three categories… The entire team should consider each alarm in the system with the same thoroughness with which they have considered the shutdown circuits… A truly critical alarm should be characterized by its separate sensing device, a separate circuitry and power source. The maintenance department should thoroughly understand the critical level of each alarm. The critical alarms and their significance should be distinctly marked on drawings, in records, and on the operating unit.
Our CSA Z463 Technical Committee debated extensively on the inclusion of alarms in this new standard, and eventually, agreed they were beyond the scope of our document. The $4-billion loss I referenced in my April column, however, was due to the loss of an alarm.
Meters are also excluded from CSA Z463, yet the Fukushima nuclear technicians resorted to raiding vehicle batteries from the parking lot because they were blind without power for their meters; this blindness compounded the reactor explosions they experienced. The IEE reports of this incident provide a chilling insight that I recommend as required reading for all levels of electrical management.
NFPA 70B Chapter 8 “Fundamentals of Electrical Equipment Maintenance” includes Design to Accommodate Maintenance, Scheduling Maintenance (this is always difficult but Annex L provides excellent direction for maintenance planners), Equipment Safety, Protective Scheme, Acceptance Testing, Guidelines and Impact of Additions/Rework to Retrofitting Equipment, Equipment Cleaning, Special Handling and Disposal Considerations (a very useful compendium of environmental hazards commonly used in the electrical industry), SCADA (another critical system below the radar of Z463) and Lubrication.
NFPA 70B Chapter 9 “System Studies” illuminates the studies (Short-Circuit, Coordination, Load-Flow and Reliability, including arc flash) that are an integral part of system design, operations and maintenance. For the non-electrical person, Chapter 10 “Power Quality” is a chest of nuggets written in layman’s terms on such problems as harmonics, interharmonics, transients, etc.
Chapter 11 “Testing and Test Methods” contains a lifetime of knowledge on Acceptance and Maintenance Tests, As-Found and As-Left Tests, Frequency of Tests, Special Precautions and Safety, Qualifications of Test Operators, Test Equipment, Forms, Insulation Testing, Low-Voltage Circuit Breakers, Transformer Tests, Protective Relays, Grounding Systems, Battery Testing, Switches, Medium- and High-Voltage Circuit Breakers, Infrared Inspection, Fuses, Insulating-Liquid Analysis, Rotating Machine Testing, Cables, Adjustable-Speed Drive Testing, Switchgear and Switchboard Assemblies, Surge Arresters, Power Factor Correction Capacitors and Emergency Systems.
Chapter 12 “Maintenance of Electrical Equipment Subject to Long Intervals Between Shutdowns” is the end result of many losses such as large rotor machines left unattended and their owners subsequently learning that they will sag and be ruined if the rotor is not incrementally rotated on a regular basis. It is especially useful as it incorporates ancillary systems, such as instrumentation and control.
Chapter 13 “Ground-Fault Protection” and Chapter 14 “Grounding” give an effective overview of these critical systems, but the standard you want in your maintenance library is IEEE 142-2007 “Recommended Practice for Grounding of Industrial and Commercial Power Systems”.
The remaining chapters cannot be learned in five lifetimes: 15 “Substations and Switchgear Assemblies”, 16 “Motor Control Equipment”, 17 “Insulated-Case/Moulded-Case Circuit Breakers”, 18 “Fuses”, 19 “Power Cables”, 20 “Cable Tray and Busway”, 21 “Power and Distribution Transformers”, 22 “Electronic Equipment”, 23 “Lighting”, 24 “Wiring Devices”, 25 “Rotating Equipment”, 26 “Vibration”, 27 “Hazardous Location Electrical Equipment”, 28 “UPS Systems”, 29 “Portable Electrical Tools and Equipment”, 30 “Reliability-Centred Maintenance”, and 31 “EPM from Commissioning Through Maintenance” but, properly implemented, they will save thousands of lifetimes.
Until next time, be ready, be careful and be safe.©
