Single Phase & 3-Phase Voltage

Today most private homes have a three-wire service. That is, the utility company connects three lines to your home’s service entrance panel: two hot conductors each supplying electricity at about 120V and one neutral conductor. Three-wire service provides both 120V and 240V capability. One hot conductor and the neutral combined provide 120V, two hot conductors combined with the neutral provide 120/240V. Typically private homes do have only single phases. If your wire sizes is # 12 AWG, then you can connect max 20 Amps. (2400W on 120 V; 4800W on 240V) Older homes may still have only a two-wire service which provides 120V. So before you buy new appliances, particularly electric heaters, check first your available power. Here is a link to how to calculate wattage for industrial heating applications or .

A three-phase system is a combination of three single-phase systems. Although 1-phase circuits are widely used in electrical systems, most generation and distribution of alternative current is 3-phase because they require less weight of conductors than single-phase loads. Also, 3-phase equipment is smaller in size, lighter in weight and more efficient than single phase machinery of the same rated capacity. 3-phase voltage is widely used for industrial heating were power requirements of several hundercWatts may be required. 3-phase permit flexibility in the choice of voltages and they can be used for single phase loads. Each singular heater has two wires; multiples of them can be connected in series or in parallel to three phases; you need the multiple of three . Otherwise you end up with an unbalanced load. Here is a link to or .

Companies usually do have 3-phase available. The 3-phases may be connected in two ways: if the three common ends of each phase are connected together at a common terminal (neutral), and the other three ends are connected to the 3-phase line, the system is wye or Y-connected. If the three phases are connected in series to form a closed loop, the system is delta connected. Here is a link to or .

Industrial Heaters are typically connected in Delta configuration, because so they can be rewired for single phase operation with no wattage change. Wattage can be reduced to one third of the designed wattage by switching from three-phase delta to wye connection. Here is a link to or .