What is the difference between three-phase voltage of the single-phase?

  • Dec 26, 2019

Almost all the tenants of apartments and houses are aware that the outlet voltage of 220 V. It is a fairly serious indicator of power, such as the potential difference will miss the strength of the current, life-threatening. But there is also industrial power supply - 380, which is used less frequently. What is a single-phase and three-phase voltage, and few know this article easy to understand and clearly explain these two concepts.

 Figure 1: Single-phase and three-phase network
Figure 1: Single-phase and three-phase network

What is a single-phase voltage?

In any dwelling present electric current for the appearance of which it is necessary to apply some tension to the conductor - or at its ends to create a potential difference. And if you look into a standard outlet, in old houses there will be only 2 wires - "phase" and "zero". In new houses for them even to join a ground wire, with yellow-green insulation.

When the home network is only one phase conductor and neutral, such a circuit is called a single-phase, and the voltage between the two conductors is 220 V. Normal potential differences, designed to operate low-power appliances. For example, for some types of electric cookers enough of one phase and it is necessary to feed 380 V.

Figure 2: Diagram of a single-phase network
Figure 2: Diagram of a single-phase network

Advantages of single-phase voltage:

  • Single-phase network is very simple in its lining and are easier to maintain in working order. Enough to bring the 2 wires - and any low-power appliance will work.
  • With proper installation faster the repair is single-phase networks, the main problem which is damage to the neutral conductor.
  • Given the fact that the single-phase network is put in houses and apartments with a total power consumption of less than 10 kW, and the cross-section of input cable can be obviously smaller. Most commonly used conductor section 4-6 mm2. And the internal wiring can not exceed 1.5-2.5 mm2.

But there is one significant drawback, because of which the single-phase network is hardly ever used in a serious industry - the inability to work with serious power devices. Machines, heating elements, some of the lights will simply not function on 220 V. Such devices require three-phase voltage.

Unlike the three-phase voltages from a single phase

Three-phase voltage, resulting from its name, involves the use of three phase conductors and one working zero. The main difference in the number of wires is not, and that the potential difference between the two "phases" is at 220 V and 380 V. And the consumer does not connect "phase" and "zero", and the two phases by applying to its terminals necessary high voltage.

Figure 3: Three-phase network
Figure 3: Three-phase network

What are the pros of three-phase voltage:

  • Ability to connect electrical appliances whose power exceeds 10 kW. It is enough to correctly identify the wires cross-section capable of withstanding such a load.
  • Three-phase networks are more efficient when working consumers.
  • Faster fault, since there is always the presence of 3 "phase", from which to choose more workable.

But the three-phase network is not perfect, since its installation must be more than the number of wires with a single-phase, and the operating voltage is more dangerous than 220 V.

Summing up

Single-phase voltage, as well as three-phase, well only under certain operating conditions the mains. For apartments suitable standard "phase" and "zero", but to establish this very flat electric furnace, it may take 2 working "phase". Therefore, you should clearly distinguish between the working conditions of the power supply: 220 V - for premises, 380 - for industrial.

It should also be remembered that the entry 380 is necessary to permit appropriate control of energy services.