Hint: The main fuse is connected between the kWh meter and distribution board of the house circuit.
Complete step by step solution:
It is given that the main fuse in a house circuit is connected to another wire carefully.
But the main fuse in a house circuit is always connected in the live wire.
Thus, the main fuse in a house circuit is connected in a live wire before the ring system.
Hence, the required option for the given question is a) in live wire before the ring system.
Additional information: The fuse is connected in series with the live wire before it enters the household circuit. This is done so because it is only the live wire which has a high potential of 200 volts unlike the neutral wire which carries zero potential. The fuse has a high rating of about 50 amperes. Thus, it prevents any damage such as fire to the entire electrical wiring entering the house due to short-circuit or overloading.
Note: A main fuse box, otherwise known as an electricity board or fuse board, is designed to operate and safeguard the electrics in your home. The live wires coming out from the output terminals of the kWh meter has another fuse in it called the main fuse.