Melting of a fuse or conductor in one or more phases causes ______.

Explanation:

A series order fault is a type of electrical fault that occurs when one or more conductors in a series circuit are interrupted. This can happen due to a blown fuse, a broken conductor, or a faulty switch. When a series order fault occurs, the current flow through the circuit is reduced or stopped completely.

The other options are incorrect:

• Double line-to-ground fault is a type of electrical fault that occurs when two conductors in a three-phase circuit come into contact with the ground.
• Line-to-line fault is a type of electrical fault that occurs when two conductors in a three-phase circuit come into contact with each other.
• Single line-to-ground fault is a type of electrical fault that occurs when one conductor in a three-phase circuit comes into contact with the ground.

Here is an example of a series order fault:

• Consider a simple electrical circuit with a battery, a fuse, and a light bulb. If the fuse blows, the circuit will be interrupted and the light bulb will not turn on.
• This is a series order fault, because the fuse is in series with the light bulb.

Series order faults can be dangerous because they can cause the voltage in the circuit to increase to unsafe levels. This can damage electrical equipment and pose a fire hazard.

The correct answer is 3) series order fault.