Assembly instructions for three-phase switchboard
Assembly order
After obtaining permission to connect to the three phases and the technical conditions, we proceed to the self-assembly of the shield. By the way, we talked about how to spend the three phases in a private house separately in the article: https://my.electricianexp.com/en/kak-provesti-380-volt-v-dom.html. The input will be mounted in an airtight box, which must be assembled on the outer wall of a private house, pipe rack or on a support (as they are popularly called, on a pillar). It has a three-phase meter and circuit breakeras shown in the photo below:
But more often the metering board is mounted behind the fence of private houses, on a support. Depending on how organized it is chosen, grounding system. Near the support, they are mounted to ground, ground on it the body of the electrical panel and re-ground the PEN conductor from the high-voltage line (according to PUE 1.7.61, Chapter 1.7) It is desirable to install the introductory machine BEFORE the counter, in which case it is installed in an additional box inside the control panel and sealed.
They do this because organizations that supply electricity must ensure that cables to the meter cannot be connected. Here divide PEN into PE and N. To do this, take two buses, connect PEN to one of them, connect the second with a jumper to the first, so it turns out that you now have two buses PE and N, and PE and N are no longer connected to each other in further sections of the circuit. It's called you organized grounding system TN-C-S.
The electrical circuit of the metering board is prescribed in the technical specifications.
In the event that the metering panel has already been installed and you have access to 2 wires (for a single-phase circuit) or 4 wires (for a three-phase) from it that go to the house, they make a switchboard in the house. They also make an earthing switch, but they are already organizing TT system, that is, PE is not connected to zero from SCH.
If 3 wires come to you from the switchgear for single-phase input, and 5 for three-phase input, then you no longer need to make an earthing switch, you have already organized power supply via the TN-C-S system or TN-S.
As you can see, the situations are different and you need to clarify in the organization that performed the installation about the purpose of the cables and the recommended grounding system.We just gave examples of different situations to help you decide what needs to be done.
But in any case, you need to understand that three- or four-pole circuit breakers are used to connect three-phase equipment, as shown in the diagram below:
The assembly of the 380 Volt metering board is carried out with a wire with single-wire (monolithic) conductors, or multi-wire (flexible) conductors, but in the latter case they are crimped nshvi tips. Recommended colors are L1 red, L2 white, L3 black, N blue, PE yellow green. To correctly assemble the three-phase shield, you need to carefully look at the protective devices on which the phase marks are applied for connecting the wires. This diagram shows four-pole protective devices RCD, with an additional terminal N, in ordinary machines this terminal may be absent. In turn, the devices installed in the panel on the DIN rail begin to commute, we measure the wire from terminal L1 to terminal L1 of the device following it, with a margin of 30%, for ease of installation and operation.
We carry out such an operation with all the terminals, however, note that cutting segments in advance is not recommended, because the process may not be long enough for convenient connection. It is even better to assemble the shield using a three-phase mounting rail, which will save space and minimize the chances of confusing something. We set separately zero bus and a PE bus, which is necessarily connected to the housing of the metering panel.
If you do not have three-phase equipment in your apartment or house, you need to assemble a 380V panel so that each phase is uniformly loaded with single-phase consumers. An example of such an assembly of a three-phase electrical panel in a private house you can see below:
In this scheme of the electric switchboard, the phases are distributed to a separate load through single-pole circuit breakers and differential switches. L1, L2 and L3 are uniformly loaded by consumers, according to the previously calculated estimated load. Learn more about how to distribute the load in phasesYou can from our article.
It is not recommended to do so - one phase for outlets, another for lighting, a third for any other needs, because It is important to distribute the load between L1, L2, L3. This is important, especially if VLEP is in poor condition and likely phase imbalance. Yes, and even load distribution increases the stability of the home electrical network and reduces the risk of knocking out the input machine due to overload in one of the phases.
To protect yourself from the effects of phase imbalance, install a voltage monitoring relay for both a single-phase network and a three-phase network. We wrote about such devices in the corresponding article: https://my.electricianexp.com/en/rele-naprjazhenija-ustrojstvo-i-naznachenie.html. You can control the load distribution using a multimeter with current clamps, which is shown in the photo below.
Well, the last option for assembling a 380 V electricity metering board is mixed, when there are three-phase and single-phase electricity consumers in the home network. In this case, you can assemble the electrical panel as follows:
Installation video tutorials
If, after reviewing the information provided, you still do not fully understand how to assemble the three-phase shield correctly, we advise you to watch videos in which the assembly order is clearly demonstrated:
That's all I wanted to tell you about how to assemble a 380v electricity metering board with your own hands. As you can see, you can connect only if you have certain skills, because When assembling, you need to take into account many nuances, such as uniform load distribution and the correct choice of the rating of machines. If you do not understand electrical engineering, it is better to entrust the matter to specialists. Remember that the avaricious pays twice, and in the case of electrical engineering - the price can be not only monetary, but also your health.
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380 I spend to connect a 9 kW water heater for heating a private house! From the meter I spend only one line 220v as There is no way to change all the wiring in the house to evenly distribute the load on all 3 lines!
Will there be a large “uneven load” when the refrigerator and the kettle are turned on, and how will this affect the voltage in the house?
Phase congestion is a problem of the power supply organization. So you can spend 3ph on the boiler and select 1ph on the rest of the email. appliances, leash the circuit breaker could withstand the load.
Greetings. Thanks for the instructive videos and articles.
Tell me what to do if from VLI 0.4 kV SIP 4x16 three wires go to the machine, and PEN immediately to the meter? This is all in the switchboard shield on the support near the house. The counter and opening machine are sealed!
From the PEN counter, the conductor or N does not know how to correctly name it goes to the bus. There are also three phases from the meter to the machine, one core from the N bus and the fifth core hanging in the air. A five-core cable goes into the house (there will be a switchboard ShchR distribution board): three wires from the machine, one core from the N bus and the fifth core hanging in the air. How to be in this case? How to organize a TN-C-S7 system Thank you in advance for your reply.
Hello! Well, in theory, the shield on the support is grounded, and apparently the grounding into the house can be organized from this circuit. In reality, apparently it turned out differently from you. Already near the house, dig a ground loop and divide the PEN into PE and N, get a TN-C-S in the usual way. But before doing this, consult about the possibility of performing such work with the supplying company. It is also worthwhile to find out why the cores in the shield remained hanging unconnected.
Hello!
The article is not bad. But please correct the mistake - the voltage between the neutral and the phase is phase.
Hello! Thanks, corrected)
Good evening.
Question on this picture https://my.electricianexp.com/wp-content/uploads/2016/03/kak-sobrat-shit-380-volt-3-768Ч639.png
They just brought 380 instead of 220 to the house, respectively, there are no three-phase consumers, the power to the consumers in the panel is distributed evenly through 4 automatic machines, but without the "differential switches" as in the picture. The question is, is it possible at first to get along with only one machine gun?
Thanks in advance