Entering electricity into the house: are three phases better or one? Simple and clear explanation

  • Dec 14, 2020
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Sooner or later, each owner of a private house has a choice: which network to connect to his home, single-phase or better three-phase? Many users think that the latter option has additional benefits, but not everyone knows which ones. Therefore, first you need to understand the concepts of single-phase and three-phase electricity input into the house.

What is a single-phase and three-phase network?

In all apartment buildings, 3 phases are brought into the entrances, but only one comes to each apartment. In the private sector, owners can choose which type of connection is more appropriate for them. What is the difference?

When three phases are connected, the user receives a high consumption power and the ability to install electrical appliances operating from an industrial voltage of 380 V. For example, a modern electric stove, the consumption of which in some models (with all burners on) reaches 5-8 kW.

In single-phase networks, it is impossible to achieve line voltage (between two "phases"), therefore, the potential difference is present here only between the "phase" and "zero", and is 220 V. For the operation of a home electrical network and not too powerful electrical appliances, it is enough, but no more.

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Pros and cons

To make an unambiguous choice, you need to know the advantages and disadvantages of different networks.

Three-phase wiring has the following advantages:

  • Higher declared power - 15 kW. Accordingly, more electrical appliances can be connected.
  • Possibility to distribute 3 "phases" between all rooms in the house. A certain reserve appears: if one "phase" disappears, 2 additional ones will always remain.

The main disadvantage of a three-phase network is the high consumption of materials during installation and a more modernized electrical panel. You will need not only additional wires, but also special protection devices, for example, three-phase circuit breakers, which are much more expensive than single-phase ones.

Figure 1: Example of completeness of a three-phase electrical panel

Separately, the cost of a three-phase electric meter should be touched upon, the price of which can be twice, or even three times higher than a single-phase device. In addition, the dimensions of such a device are not small - it may also be necessary to change the shield, since the meter simply does not fit in it.

Figure 2: Three-phase electricity meter

What are the advantages of a single-phase electrical network:

  • Easy to connect. Only 3 wires: phase, neutral and ground.
  • Cheaper filling of the switchboard. Only single-phase circuit breakers, RCDs, voltage relays, etc.
  • Less costly troubleshooting.

But there is one significant drawback in a single-phase network - it is the inability to step over the declared 7 kW. And some homeowners want not only to equip a dwelling, but also to put a couple of convenient machines in the garage. Figure 3: One of the options for three-phase wiring in a private house

What to choose? Outcome

The answer is unequivocal: a three-phase network is much better than a single-phase one, even with all its disadvantages. It is better to spend money once and connect 3 "phases" to the house than to choose a single-phase input and remake it in the future. This is a classic example of the saying "the miser pays twice."