Electrical Myth
While searching through the forums recently, I came across two posts in which an old electrical myth is repeated- "Circuit breakers will trip at 80% of their rating." For any breaker which has not deg...
Forum Discussion
Having designed a lot of electronic equipment, some of which used fuses and some used breakers, I got pretty familiar with the various types of these protection devices.
With fuses there are three basic types:
Circuit Breakers also come in three different "flavors":
Ref: Understanding Overcurrent Circuit Protectors - IEEE.
With fuses there are three basic types:
- Standard (fast blow):
Will carry rated current for one minute or blow in one second at 2X rated current. - Ultra-fast blow:
Will carry rated current for one second or blow in 1/10 second at 2X rated current. - Slow blow:
Typically used in motor circuits with high inrush currents.
Characteristics vary by manufacturer.
Circuit Breakers also come in three different "flavors":
- Magnetic:
Will trip at rated current. - Thermal:
Will carry rated current for one minute or trip in one second at 2X rated current. - Magnetic/Thermal Hybrid:
Characteristics vary depending on use and manufacturer.
Ref: Understanding Overcurrent Circuit Protectors - IEEE.
