AC or DC?
High voltage AC has the advantage of being efficiently conducted over very long distances with relatively low transmission losses. AC has thus become the standard for industry and domestic usage. DC is generally used in low voltages, where transmission efficiencies are low. In some cases however, DC does have the advantage of efficiency in operation; as much as twice that of AC for some applications. A disadvantage of DC is that many appliances and equipment in 12 Volt DC versions are hard to find and are expensive.
Both have their advantages. In telecomm and water pumping systems, we generally use all DC. In home systems we typically run all or the majority of loads with AC power. For maximum efficiency certain specific loads can easily be powered by DC circuits. Cabins or RV's use mostly DC and can use regular gauge wire because of small loads and short transmission distances.
