– Is the provider experienced in complex electrical calculations?
Arc-flash calculations are an extension of traditional fault energy (short-circuit) calculations. Providers who are already highly experienced in fault calculations have the best background for performing Arc-flash calculations.
Power Analysis Associates engineering staff have been teaching and providing fault energy calculations for over twenty years.
– Can the provider’s technical personnel optimize the systems breaker settings for minimizing arc-flash hazard levels at the panels?
Arc-flash energy is an integration of flash intensity and flash duration resulting in heat energy density which is expressed as calories per square centimeter. The electrical system should be designed and adjusted for the optimum combinations of fault energy level and OCP clearing times to minimize the resulting arc-flash hazard levels.
All Power Analysis studies are under the direction of a registered professional engineer with extensive training in energy release minimization in electrical systems.
– Has the provider previously been selected by others for complex electrical calculations?
One of the best measures of a provider’s experience and competency are the types of projects they are selected for by other clients.
Power Analysis Associates was retained and performed the electrical calculations for the new World Trade Center #7, the Time Warner Towers, the Hearst Corporate Center in New York City, Rentchler Stadium in Hartford, Connecticut as well as the very largest Department of Defense construction projects.
– If you have multiple plants with facilities in other states can your provider handle the on-site plant survey and training work?
Not all providers will be equipped to provide on-site services such as plant surveys and electrical safety training anywhere in the nation.
Power Analysis Associates has offices on both coasts and Hawaii and regularly provides on-site services to all fifty states.
– Does the provider have the capability of offering a full range of services – plant surveys, one-lines, fault studies, arc-flash, labeling, on-site safety training, and document maintenance?
It is important that a provider has all of the services needed within one organization starting with the initial on-site plant survey continuing through the full range of studies to training and documentation maintenance. Critical errors can be made when data has to be transferred from one organization to another. A comprehensive electrical safety program is a significant investment and should be protected by continued support and maintenance by the provider.
Power Analysis Associates offers all of the services you will need – plant surveys with Master Electricians, a full range of electrical studies and analysis by Registered Engineers, CADD generated one-lines, arc-flash labeling, on-site safety training, power quality analysis, and document maintenance for protection of your investment.
– Does the provider have professional level integrated software for performing complex electrical studies?
Some providers may be limited to manual or Excel spread sheets for their calculations or have a limited version integrated package. Some providers are not equipped for scanning, creating, and plotting CADD drawings for your one-lines.
Power Analysis Associates has multiple copies of the full range of SKM software with full 2000 bus capability for handling the largest and most complex electrical systems.Power Analysis also has a complete engineering and CADD department for generating and maintaining all levels of technical documentation and drawings.
– What Panels and Voltage/Phase Configurations need be considered for Arc Fault Calculations?
Because 480V systems inherently have higher fault currents than other voltages they have been of prime concern for arc fault analysis in industrial systems. The reason is not the voltage per se, but the fact that 480 volt service is usually fed from larger transformers and larger feeder cables.
Due to the preponderance of 480V systems being analyzed it is often assumed that NFPA 70E applies only to 480V systems. In fact the NFPA 70E does not state what voltage systems should be analyzed, except to include all voltages over 50 V.
The question becomes – how does one determine what voltages apply for arc flash analysis? It is dangerous to generalize, as under special conditions even 120/240 volt systems could constitute a hazard. As a general guideline fault current on systems less than 240 volts is only significant when the source transformer is in the range of 100 kVA and has very low impedance. If a comprehensive one-line is generated (as we do)then all panels and voltage configurations become part of the one-line and subsequent fault analysis as well as the arc-flash analysis.