Three-core wires

 

— a three-core wire can be used, in particular, in both single-phase and three-phase networks. With three phases, this is the minimum required to connect the load to the power source (however, for different purposes, a different number of cores may be required — up to five; for more details, see special sources). In single-phase networks, three cores make it possible to supplement the “zero” and “phase” with a ground wire, which is extremely important for the safe operation of some electrical appliances.