A three phase system will have 3 phase branch circuits and no neutral.
For a three phase distribution system there is one neutral. In North America the electrical code allows three individual branch circuits to connect with one neutral as long as the three circuits each use an individual phase leg. This differs from 120/240 volt single phase wiring where only two legs can be used with one neutral.
Yes. You are allowed to use a neutral for one circuit from each phase of your service. For example, in a residential service, you can use the same neutral for circuits 1 and 3. In a commercial (3 phase) service, you can use a neutral for circuits 1, 3, and 5. You will experience problems if you use a neutral for two 'black' circuits or two 'red' circuits, if the circuits originate from the same phase bus bar. Also, AFCI's are sensitive to sharing neutrals, but GFCI's are not.
You can divide a three phase service into (3) single phase circuits providing you have a 4th neutral wire.
The question makes no sense.
Yes, this is done on star (wye) systems where one neutral is used for three phase wires. e.g. 120/208 voltage system.
The neutral in single phase AC circuits is used as the common power return conductor for half phase operation. In a typical (US/Canada) 120/240 split phase system, generally used in residential applications, the voltage between neutral and either of the two hot conductors is 120 VAC, and the voltage between the two hot conductors is 240 VAC. Neutral is also grounded at the distribution panel, as well as at the utility distribution transformer, in order to limit the voltage of any conductor relative to ground, and also to be able to detect ground faults by sensing imbalance between neutral and hot currents. Note that this is not called two phase power. It is single phase, or split phase, and it comes from one center tapped transformer winding. The center tap is neutral.
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a traditional rcd wont work as it uses the difference between the incoming active and neutral to detect current loss it has to read 0. In particular, an RCD alone will not detect overload conditions, phase to neutral short circuits or phase to short circuits. Over-current protection must be provided.
Your incoming 208V 3 phase power supply will also need an incoming neutral of the same conductor size. Then any single pole breaker installed in the panel will have 110 volts to the neutral. That is you can run 208V 3 phase motor circuits from a three phase breakers in the panel and any number of 110V circuits from single pole breakers.
The neutral provides a path back to the source for the electricity. In a three-phase circuit, it is mainly used to carry the unbalanced load back to the source. In theory, a perfectly-balanced three-phase circuit would not need a neutral, but this is almost impossible to achieve in actual practice.
yes we can use as a single phase circuit because at practise directly the 3-phase circuit is made by combining the three single phase circuits
The formula to use is, phase voltage /1.73 = phase to neutral (ground) voltage.CommentThere is no such thing as a 'phase to phase', or 'phase to neutral' voltage. The correct terms are 'line to line' and 'line to neutral'. So the above answer should read: line voltage/1.73= line to neutral voltage = phase voltage.