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Fuse Calculation Formula:
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Fuse current calculation determines the appropriate fuse size based on the load current. The standard practice is to select a fuse that is 125% of the continuous load current to provide proper protection while allowing for normal operation.
The calculator uses the fuse calculation formula:
Where:
Explanation: The 1.25 multiplier provides a safety margin that allows for normal current variations while ensuring the fuse will blow during overload conditions.
Details: Correct fuse sizing is crucial for electrical safety. An undersized fuse may blow unnecessarily, while an oversized fuse may not provide adequate protection against overloads and short circuits.
Tips: Enter the load current in amperes. The value must be greater than zero. The calculator will provide the recommended fuse size with a 125% safety margin.
Q1: Why use 125% as the safety factor?
A: The 125% factor provides adequate protection against overloads while allowing for normal current variations and inrush currents during startup.
Q2: When should I round up the fuse size?
A: Always round up to the next standard fuse size. Electrical codes typically require using the next available standard size when the calculated value falls between standard ratings.
Q3: Are there different safety factors for different applications?
A: Yes, some applications may require different safety factors. The 125% factor is standard for general purpose applications, but specific equipment or codes may dictate different requirements.
Q4: What about motor starting currents?
A: Motors with high starting currents may require time-delay fuses or different sizing considerations to accommodate the temporary inrush current.
Q5: Should I consider ambient temperature?
A: Yes, high ambient temperatures can affect fuse performance. In high-temperature environments, you may need to derate the fuse or consult manufacturer specifications.