Question

what does the A written on the fuse refer to

Answer 1

A fuse is a protective device in an electric plug or circuit that contains a piece of wire designed to melt and break when there is a fault, and an excessive current flows along it for a particular time. ... A fuse or a circuit breaker is normally used as a disconnector.

the voltage ratings is G, which means the fuse should be used in a circuit where the voltage is 250 volts or less. After this is a set of three numbers and the letter "R," which represent the current rating of the fuse. The "R" indicates the decimal point.