Short-Circuit Current Ratings, Interrupting Ratings, and the Intersection of UL 508A and the NEC

Short-circuit current ratings (SCCR) and interrupting ratings form the backbone of electrical safety, coordination, and compliance in modern power systems. This presentation explores how UL 508A Supplement SB intersects with the National Electrical Code (NEC) to define the limits of what electrical equipment can safely withstand and interrupt under fault conditions.
The presentation examines how UL product listings and component ratings interact with NEC Articles 409, 110.9, and 110.10, clarifying how available fault current, protective device selection, and equipment labeling all converge in practice. Real-world examples will illustrate how engineers can properly determine SCCR, verify interrupting ratings, and ensure that the overall system meets both code and product standard intent.
Key Topics
– Fundamentals of SCCR and interrupting ratings
– Relationship between UL 508A Supplement SB and NEC Articles 409, 110.9, and 110.10
– Evaluating equipment for compliance and labeling accuracy
– Case studies from industrial and institutional systems
Speaker(s): Tyler Shewbert,
Agenda:
No-host social at 5:30pm
Presentation at 6:00pm
Dinner at 7:00pm
Presentation continues at 7:45pm
Adjourn by 8:30pm
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