Wireing for direct current is generly the same as for AC.
In years gone by, the switches and outlets were also the same as used for AC, but these days most switches and socket outlets are only listed for AC operation.
Years ago switchs and sockets were marked AC/DC indicating suitability for either system.
Direct current does not normally produce any hum or other noise.
DC is used today in off grid homes, being obtained from batteries charged by solar modules. The voltage is normally much lower than DC mains supplies, 12 or 24 volts often being used.
In theory such systems should use special DC switches and outlets, in practice standard AC ones are used and work perfectly. In general, a switch marked "AC only" can be used on DC ,provided that the voltage is limited to about 10% of the rating. Therefore a switch marked as being for 240 volts AC only can be used on a 12 or 24 volt DC system, but certainly not on a 240 volt DC system.
