An toànCâu 424 / 521
What is the difference between a Class A (personnel) GFCI and a 30-milliampere 'equipment' ground-fault protection device?
a.A Class A GFCI (about 5 mA) protects people from shock, while a 30 mA device protects equipment/wiring against fire and is not intended for personnel protection
b.They are identical in function
c.The 30 mA device protects people better than the 5 mA device
d.Only the 30 mA device is allowed on construction sites
Giải thích
Class A GFCIs trip near 5 mA to protect people from electric shock, while equipment ground-fault protection (up to 30 mA) is designed to protect wiring and equipment and limit fire risk, not to protect a person. A 30 mA trip point is too high to reliably prevent a dangerous shock.
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