Little concern in the past has been given to the size, gauge, or composition of wire as associated with wiring a dollhouse. Different wire handles varying amounts of electrical current dependant on its size and composition. As an example: Copper wire conducts electrons better than Aluminum. Gold or silver conducts better than Copper. Furthermore, 32 AWG (gauge) wire will not carry as much current as 24 AWG. The larger the gauge number, the smaller the wire diameter.
Creative Reproductions 2 Scale offers only a few different wires to choose. I also recommend the use of flat tape and tend to use both the flat tape and round wire in my wiring. The wires below are specially constructed to handle larger currents than the average for the paticular guage.