On three phase services over 200 amps the electrical code allows the electrical contractor to reduce the size of the neutral wire . This saves the customer money. There are conditions as to how much the neutral can be reduced but it is not as low as half the supply conductors. The reason that the neutral can be reduced is that it only carries the unbalanced current on the three phase four wire system.
The current carried by the neutral of a three phase four wire system is the un balanced current. If the three phase system was completely balanced on all three phases there would be no need for a neutral, eg a three phase motor. This neutral current will be less that the phase current so a reduction in the neutral size is allowed.
By rule of thumb, the neutral conductor is half the size of main conductor.
In a 3.5 core cable, the neutral conductor carries less current compared to the phase conductors. By reducing the size of the neutral conductor to half, it helps balance the voltage drop and prevents overheating in the cable. This helps ensure the safety and efficiency of the electrical 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.
No, in a three phase balance load, there should not be any current through Neutral conductor. If it is a 2 wire, single phase system, the Neutral will carry the same current as live conductor if the system has no Earth fault, leak.
They are both types of AC circuit. A single-phase supply is carried on two wires, a live and a neutral. The neutral is different from the live because it is grounded at the supply transformer. A three-phase normally has three live wires and a neutral, and it can be used for three separate single-phase supplies to adjoining properties for example, with each property connected from one live wire to the neutral. The three voltages are timed or 'phased' to peak one third of a cycle apart. If each property was drawing an identical current, the sum current in the common neutral sums to zero, and therefore the neutral has no current in it and therefore incurs no power losses. Thus the losses are half what they would be for three separate single-phase supplies each with its own neutral. If there were three hundred properties instead of three, the current in the three live wires would be nearly equal nearly all the time, and again the current in the common neutral would be near zero. This system allows power to be transmitted over distance using half the mass of wire.
No. Radius is half of the diameter.
in case of motor, only 3core cable are used. Because there is phase balence between the winding. But in case of wiring,panel installation, 3.5c cables are normally used. Because there is unbalenced between the phase current. So the neutral taken to give the return path to flow of unbalenced (rush) current. Which always less than phase current,so the neutral cable is take half of the phase cable.
You can measure a small voltage between earth and neutral, even if the neutral is grounded to earth, because the neutral conductor acts as an antenna picking up electromagnetic radiation in the atmosphere. -------------------------- If the above answer were true, the earth conductor would also act as an antenna. But the real answer is, if you read ANY voltage between the neutral and earth, the neutral is broken somewhere between where you are measuring and the panel or not properly bonded in the panel. Call a competent electrician to repair the problem.
Yes, a radius IS half of a diameter
the radius is half of a diameter
Yes. The radius is half the diameter.