Simply connecting a power supply to a load is not always so simple. Voltage drop due to wires, cables, connectors and circuit board traces can cause considerable regulation errors at the load. It is not uncommon for some applications to have long wires between the power supply and the load. In these applications, as the load current increases, the voltage delivered to the load drops, with the result appearing as if there is a load regulation issue with the power supply.
Linear Technology, Voltage regulation