Search results
Results from the WOW.Com Content Network
Lighting and general purpose receptacles are at 120 volts AC, with larger devices fed by three wire single-phase circuits at 240 volts. In commercial construction, three-phase circuits are often used. Common 3 phase configurations within a building are 208v/120 wye, 120/240 center tapped delta and 480v/277v wye. Lighting is usually fed by 277 V ...
Minimum wire size for hand-held or portable equipment is usually restricted by the mechanical strength of the conductors. Many areas, such as the US, which use (nominally) 120 V, make use of three-wire, split-phase 240 V systems to supply large appliances. In this system a 240 V supply has a centre-tapped neutral to give two 120 V supplies ...
For example, in North America, a unique split-phase system is used to supply to most premises that works by center tapping a 240 volt transformer. This system is able to concurrently provide 240 volts and 120 volts. Consequently, this allows homeowners to wire up both 240 V and 120 V circuits as they wish (as regulated by local building codes).
Most of the Americas use 60 Hz AC, the 120/240 volt split-phase system domestically and three phase for larger installations. North American transformers usually power homes at 240 volts, similar to Europe's 230 volts. It is the split-phase that allows use of 120 volts in the home. Japan's utility frequencies are 50 Hz and 60 Hz.
The TT-30R receptacle is commonly available in nearly all RV parks in the United States and Canada, and all but the largest RVs manufactured since the 1970s use this plug to connect to power feeds. [citation needed] The appearance of this plug is sometimes confused with a NEMA 10 connector, rated for 240 V, but the NEMA TT-30 is a 120 V device.
However, 130/225 V, three-wire, two-phase electric power discontinued systems called B1 are used to run old installations in small groups of houses when only two of the three-phase high-voltage conductors are used. The phase shift in Europe is 120°, as is the case with three-phase current. That's why we calculate 130V * √3 = 225V.
Connecting a load between the hot wire and the neutral gives 120 volts, which is used for lighting circuits. Connecting both hot wires gives 240 volts for heavy loads such as air conditioners, ovens, dryers, and electric vehicle charging stations. In Europe and other countries using its system, the secondary is often the three-phase 400Y/230 ...
In the United States it is not usually used for three phase power but for the high leg delta wiring of split-phase electric power (unknown in Europe). This allows one to choose single-phase AC power at either 110–120 volts between phase and neutral or 220–240 volts between phase and phase.