Direct connection of the three-phase TEN 380 volts connection circuit The most common question requires a precise configuration of the windings, since the wrong choice between a โstarโ and a โtriangleโ leads to either the heater burning out or underheating. If you plan to install TAEN At 380 volts in an electric boiler or industrial furnace, the first step is to verify the deviceโs passport data with the parameters of your power grid. Incorrect switching of phase wires or ignoring the need for zero conductor in certain circuits can cause failure of expensive equipment and the occurrence of emergency situations.
> โ ๏ธ Attention: Before starting any electrical work, it is necessary to completely de-energize the shield and make sure that there is no voltage on the current parts using a multimeter.
The main difference between industrial heaters and household heaters is their ability to work in networks with a linear voltage of 380 V. Unlike the standard 220V, it uses a three-phase system, where the voltage between any two phases is exactly 380 volts. A properly assembled electrical circuit provides a uniform load on all three phases, which is critical for the stable operation of the entire power system of the building. Connection of TEN 380 is performed according to one of two main schemes, the choice of which depends on the nominal voltage of the heating element itself.
It is critical to understand that if the TEN is designed for 220 volts, it cannot be connected according to the scheme of the โtriangleโ in the network of 380 volts โ it will instantly burn. Conversely, a 380-volt element, when connected by a star in a 380-volt network, will work, but only give out a third of its power. Therefore, visual inspection of markings and reading of technical documentation are mandatory procedures before installation.Principal differences of the Star and Triangle circuits
The choice between the connection "star" and "triangle" is based solely on the nominal voltage indicated on the housing. TEN 380 volts. In the star scheme, the ends of all three heating elements are connected to one common point (neutral), and the beginnings are connected to phases A, B and C. In this case, a phase voltage equal to 220 volts is applied to each TEN. This is ideal for heaters designed specifically for 220 V, provided that there are 380 V in the network.
The scheme "triangle" implies a sequential connection of the ends of one element with the beginning of another, forming a closed circuit. In this case, a linear voltage of 380 volts is brought to each TEN. If you connect a 220V element using the โtriangleโ scheme to a 380V network, the current through it will increase 1.73 times, which will lead to thermal destruction of the nichrome spiral in fractions of a second. TEN connection scheme 220B is only a zero star, 380B is a triangle or star (depending on the design).
- ๐บ Star: Suitable for TENs marked 220V in a three-phase network 380V, requires the mandatory presence of zero wire.
- ๐บ Triangle: Designed for TENs with the marking 380V, provides full passport power without the use of neutral.
- ๐บ Power: When switching from a star to a triangle, the power increases 3 times, which must be taken into account when calculating.
It is important to note that some industrial heaters have already implemented an internal connection. Such devices may have only three or four outputs. If there are three conclusions, it is usually a ready-made block for a triangle or star circuit without the possibility of change. If there are six conclusions (two for each TEN), then the configuration can be changed. Connection of TEN 380 In this case, it gives flexibility in power management and temperature.
Power calculation and choice of protective automation
Before installation TEN 380 volts It is necessary to make an accurate calculation of the current load for the correct selection of automatic switches and cable cross-section. The power of the three-phase heater is composed of the power of all its phases. To calculate the current strength in the three-phase network, the formula is used: I = P / (โ3 ร U ร cosฯ), where P is power, U is voltage (380 V), and cosฯ for active load (TEN) is taken to be 1.
For example, for a 12 kW TEN, the calculation would look like this: 12,000 / (1.73 ร 380) โ 18.2 Ampere. Based on this value, an automatic switch with the nearest large standard denomination, usually 20A or 25A, is selected. The cable is selected according to the tables of the PUE, taking into account the method of laying and the material of the veins (copper or aluminum). TEN connection scheme It will not be safe without properly selected protection against short circuit and overload.
To protect a person from electric shock, it is necessary to use a protective shutdown device (CCD) or a differential automatic. Leakage current for stationary heating appliances in dry rooms can be 30 mA, but for wet rooms (baths, pools, washing rooms) it is recommended to install a RCD with a leakage current of 10 mA.
Always keep a margin of about 10-15% in the power of the machine to avoid false positives when voltage surges in the network.
Step-by-step instruction for connecting TEN 380 Volts
The installation process begins with the preparation of the workplace and the inspection of the completeness. Make sure you have access to all the heater terminals and the introductory shield. TEN 380 volts connection circuit The one considered requires the use of a three-core (for a triangle) or four-core (for a star) copper cable of the corresponding cross-section. Clean the ends of the wires by 10-12 mm, avoiding damage to the veins themselves.
The connection is performed in the following sequence:
1. Prepare the cable and clear the insulation.
2. Connect phase wires L1, L2, L3 to the corresponding terminals of the TEN.
3. If the scheme is a star, connect the free ends of the TENS with a lintel and connect a zero wire N to it.
4. Ground the heater body by connecting the PE wire to the ground circuit.
โ๏ธ Checklist before first launch
After assembly of the chain, it is necessary to check the quality of the connections. Poor contact in the terminal box will lead to local overheating, oxidation and eventual burnout of contacts. Use a dynamometer key or force recommended by the manufacturer to tighten the screws. Connection of TEN 380 is completed by installing a protective casing on the terminal.
Diagnosis of faults and verification of TEN
During operation, heating elements can fail. The main symptoms of malfunction: the device does not heat, knocks out an automatic switch or an ultrasound, the body is electric. Primary diagnosis is carried out by a multimeter in the resistance measurement mode. For a working TEN, resistance is calculated by the formula R = U2 / P.
If the multimeter shows infinity (cliff), the spiral has burned out and the TEN is to be replaced. If the resistance is close to zero, a short circuit occurs. Particular attention should be paid to the insulation test. The resistance between the terminals of the TEN and its metal body should be infinitely large.
Table of power and resistance correspondence
For TEN 220V 1kW resistance โ 48 Om| For TEN 220V 2kW resistance โ 24 Om| For TEN 380V 3kW resistance โ 48 Om| For TEN 380V 6kW resistance โ 24 Oms
> โ ๏ธ Attention: If the vertebra revealed resistance between the contacts and the body less than 10 MH, to operate such a TEN is prohibited - it is deadly dangerous.
A frequent cause of breakdown is scale, which worsens heat transfer and leads to overheating of nichrome. Visually, this can manifest itself in the bloating of the TEN tube. In such cases, even a good electrical circuit will not save the device from destruction. TEN connection scheme It should be checked regularly for contact burns.
Table of selection of cable cross-section and nominals of automatic machines
For ease of selection of components below is a reference table for copper cables at a voltage of 380 volts. The data are relevant for standard gasket conditions and temperature regimes.
| Power TEN (kW) | Current (A) | Automatic (A) | Cable cross-section (mm2) |
|---|---|---|---|
| 6 kW | 9.1 | 10-13 | 1.5 |
| 9 kW | 13.7 | 16 | 2.5 |
| 12 kW | 18.2 | 20-25 | 4.0 |
| 15 kW | 22.8 | 25 | 4.0 |
| 24 kW | 36.5 | 40 | 10.0 |
When choosing a cable, consider the length of the track: at distances of more than 50 meters, it is better to increase the section by one step to compensate for the voltage drop. TEN 380 volts with an understated voltage at the terminals will warm weaker, since the power drops proportionally to the square of the voltage.
Frequent errors in installation and their consequences
One of the most common mistakes is ignoring grounding. The housing of the thermal power plant in the process of operation is under the potential of the network, and a breakdown of the insulation on the housing without grounding will lead to an electric injury. It is also often forgotten to extend the terminals after the first heating as the metal expands and the compound weakens.
Incorrect choice of circuit (star instead of triangle or vice versa) leads to either combustion of the device or its inefficient operation. If the TEN 380V is included in the "star" at 380V, it will warm, but very weakly. If the TEN 220V is included in the โtriangleโ at 380V, it will burn instantly. Connection circuit TEN 380 volts It should be checked before feeding.
The main rule: The nominal voltage of the TEN should coincide with the phase voltage in the Star scheme or linear in the Triangle scheme.
Another mistake is the use of aluminum wires without special adapters or lubrication. Aluminum flows under pressure and is oxidized, which leads to heating of the contact. Use only copper wires or special alumoma copper tips and pastes.
Can I connect the TEN 380V to a single-phase 220V network?
Technically, you can connect, but it will work incorrectly. If you turn on one TEN 380V between phase and zero (220V), its power will drop by about 3 times. It is impossible to use the full power of a three-phase thermal power plant in a single-phase network without the use of a transformer or frequency converter, which is economically impractical.
Why does he knock out the RCD when he turns on the TEN?
This may indicate a breakdown of the insulation of the heating element on the body, the accumulation of moisture in the terminal box or the malfunction of the RCD itself. Also, the cause may be a natural leakage of current, if the total power of all devices exceeds the threshold of sensitivity of the device.
How to determine the burnt TEN or not without a multimeter?
Without measuring instruments, it is difficult to accurately determine the condition. An indirect sign may be the lack of heating with a serviceable machine and the presence of voltage at the terminals. However, for reliable diagnosis, the use of a tester (multimeter) is mandatory.
Does a zero need for a TEN 380 volts?
For the scheme "triangle" zero wire is not needed, three phases and grounding are enough. For the scheme "star" zero is necessary if the TEN is designed for 220V. If the TENs are 380V, they can work in a star without zero, but this is an unusual situation that requires clarification in the product passport.