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Self-Test 1 Q&A 4-6
Self-Test Questions Volume 1
Question | Answer |
---|---|
Name the two types of plug fuses. | Edison base and type S. |
Explain the conditions under which an Edison-base fuse panel can be installed | An Edison fuse panel can be installed only when it is modified by inserting adapters in the fuse holders to accept type S plug fuses. |
List the amperage ratings for type S plug fuses | 0-15 amperes, 16-20 amperes, and 21-30 amperes |
What is the maximum capacity of amperes for ferrule-type cartridge fuses? | 60 amperes. |
Why can't a 60-ampere, ferrule type be used in place of a 20-ampere, ferrule type? | Fuse diameter and length increase as amperage and voltage increase |
What is the weakest part of an electrical circuit? | The fuse. |
How does a thermal-type circuit breaker work to interrupt the circuit on an overload? | A thermal type has an element within the breaker that responds to temperature change. When the current flow reaches a set level, the element bends enough to trip the latch. This opens a set of contacts to break the circuit. |
How does a magnetic type of circuit breaker open the circuit on an overload? | A magnetic-type circuit breaker responds instantaneously. A small electromagnet actuates the breaker mechanism. Enough magnetic flux is created to attract a small armature. As the armature moves, the breaker mechanism trips and opens the circuit. |
What is the advantage of a magnetic circuit breaker over a thermal type? | It opens the circuit instantaneously when there is an excess of current flow. |
What is the purpose of a GFCI? | A GFCI used as extra protection on circuits where the potential of having a ground though the user is higher. |
Where must ground fault breakers be installed in a home? | All 120-volt, single-phase, 15- and 20-ampere receptacles in bathrooms, garages, and outdoors. |