1. What is the Breaker Size Calculation?

The breaker size calculation determines the appropriate circuit breaker rating based on the continuous current load. It follows the National Electrical Code (NEC) requirement of sizing breakers at 125% of the continuous load current.

2. How Does the Calculator Work?

The calculator uses the breaker sizing formula:

Where:

• \( \text{breaker} \) — Circuit breaker size in amperes
• \( I_{\text{continuous}} \) — Continuous current load in amperes
• 1.25 — NEC required multiplier for continuous loads

Explanation: The 1.25 multiplier ensures the breaker won't trip under normal continuous load conditions while still providing overload protection.

3. Importance of Proper Breaker Sizing

Details: Correct breaker sizing is critical for electrical safety - preventing both nuisance tripping and dangerous overcurrent conditions that could lead to equipment damage or fire.

4. Using the Calculator

Tips: Enter the continuous current load in amperes. The value must be greater than zero. The calculator will output the minimum recommended breaker size.

5. Frequently Asked Questions (FAQ)

Q1: What defines a "continuous load"?
A: NEC defines continuous load as any load expected to continue for 3 hours or more.

Q2: Can I round up the breaker size?
A: Yes, you should round up to the next standard breaker size after applying the 1.25 multiplier.

Q3: What about non-continuous loads?
A: For non-continuous loads, the breaker can be sized at 100% of the load current.

Q4: Are there exceptions to this rule?
A: Some specific equipment like motors have different sizing requirements - always check applicable codes.

Q5: What if my calculated size isn't a standard breaker rating?
A: Always round up to the next available standard size (15A, 20A, 30A, etc.).