Which of the following statements about electrical safety is correct?
- AIf a device is double insulated, it does not need a fuse.
- BA device that has a normal operating current of $3.0\,\text{A}$ must be protected by a $3.0\,\text{A}$ fuse.
- CSwitches must always be connected into the live supply wire.
- DThe metal casing of an electrical device must be connected to the neutral wire.