What are standard ampere ratings typically used for fuses and inverse time circuit breakers?

Standard ampere ratings for fuses and inverse time circuit breakers are typically established to provide flexibility and adequacy for protecting electrical circuits without undue risk of nuisance tripping or damage from overloads.

The correct set of ratings includes 15, 20, 25, and 30 amperes, which reflects commonly used values for residential and commercial circuits. For instance, 15 and 20 ampere breakers are standard for lighting and receptacle circuits, while 30 ampere breakers are often found in larger branch circuits requiring more power, like those for certain appliances or equipment.

The other options present either too limited a range or include inappropriate values. For instance, the first set, featuring 5, 10, 15, and 20 amperes, lacks higher ratings, making it insufficient for circuits that require more than 20 amperes. The second set begins at 10 amperes, then lists 15, 20, and 25, but again it does not cover the commonly used 30 amp rating, thus limiting its applicability. The last option includes fractional values and higher ratings such as 70 and 90, which are typically not standard for most common applications and do not align with regular residential circuit requirements.

Hence