Can Your Electrical Equipment Withstand System Faults?

During a system fault (short circuit), the surge of electrical current injects large amounts of heat and magnetic force into the system, creating the potential for--

  • Injured (or worse) personnel.
  • Damaged or destroyed equipment.
  • Lost production and facility downtime.

Protective devices--circuit breakers, fuses, etc.--attempt to interrupt this destructive force as quickly as possible. Meanwhile, other equipment like buses, panels, and transformers try to weather the spike with minimal disruption to operations. Both of these reactions can happen only if system components are properly rated for the available fault current.

Section 110.9 of the National Electrical Code® (NFPA 70™) states that protective devices must have short circuit interrupting ratings “sufficient for the current that must be interrupted.” In other words, these devices--as well as the equipment they protect--must be able to handle the fault currents they face. Those that can are properly rated; those that can’t are over-dutied.

A Short Circuit and Equipment Evaluation Study by D.L. Steiner ensures your protective devices and other system components meet this important NEC standard. Our study features-–

  • Thorough system data collection: utility fault current, transformer nameplates, panel/device information, feeder sizes/lengths, etc.
  • Evaluations of all relevant system operating scenarios (using analysis software such as SKM Power*Tools).
  • A study report that includes (1) maximum symmetrical/asymmetrical fault levels at all locations; (2) rating-vs.-fault duty comparisons for all equipment, with pass or fail marked for each device; and (3) recommendations for what to do about failed equipment.
  • An up-to-date single-line diagram of your electrical system.

Every System Will Fault

It’s generally accepted that every electrical system will fault at some point. When that fault occurs, a Short Circuit and Equipment Study completed now allows you to be certain your system is rated to withstand the impact.*


* A Short Circuit and Equipment Evaluation Study provides roughly 80 percent of the analysis required to implement a complete arc flash hazard safety program your company’s electrical system.


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