ICC Residential Electrical Inspectors Practice Exam

What percentage of the branch circuit rating can the total rating of utilization equipment fastened in place exceed?

1. 25 percent

2. 50 percent

3. 75 percent

4. 100 percent

The correct answer is: 50 percent

The total rating of utilization equipment fastened in place can exceed the branch circuit rating by a maximum of 50 percent. This stipulation is based on the guidelines found in the National Electrical Code (NEC), specifically under Article 210.23, which addresses the load calculations for branch circuits that supply fixed appliances and similar equipment. When equipment is permanently installed, it is often grouped together on a circuit. The 50 percent allowance takes into account the fact that appliances can have varying usage patterns and may not all operate at the same time at full capacity. Thus, the Code recognizes that, to accommodate these variations and ensure safe operation, it's acceptable to allow for a total rating that exceeds the circuit rating by this percentage. Adhering to this guideline helps ensure that circuits are not overloaded and promotes safety in residential electrical installations. This understanding is vital for inspectors to ensure compliance with safety standards and to prevent potential hazards associated with overloaded circuits.