How do electrical low voltage systems work

Low voltage consumers

From the energy distribution planning compendium

Most LV supplies in Europe are between 230/400 V 3-phase with four active conductors.

Consumers with a power consumption of up to 250 kVA can be supplied from the low-voltage network.

According to IEC 60038 (VDE 0175-1) CENELEC standard voltages, this voltage value must be used uniformly for 3-phase four-wire systems of 230/400 V in Europe.

By definition, low-voltage consumers are customers whose consumers can be sufficiently supplied with electrical energy via the low-voltage system at their location.

The voltage of local LV networks can be 120/208 V at 60 Hz or 230/400 V at 50 Hz (lower or upper limit values ​​of most commonly used 3-phase voltage values) or in between - as in IllustrationC1 shown.

The standard IEC 60038 (VDE 0175-1) recommends an international voltage value for 3-phase four-wire LV systems of 230/400 V, which must be adhered to throughout Europe. With regard to the range of the supply voltage under normal operating conditions, the supply voltage should not deviate by more than 10% from the nominal voltage of the network.

Consumers with a power consumption of up to 250 kVA can be supplied from the low-voltage network. In general, the network operators offer a connection to the high-voltage network even with a lower power requirement, when the capacity of the low-voltage network is almost exhausted.

country Frequency & tolerance
(Hz &%)
Residential building (V) Commercial
Building (V)
Industrial building
(V)
Afghanistan 50
380/220 (a) 380/220 (a) 380/220 (a)
Egypt 50 ± 0,5 380/220 (a)
220 (k)
380/220 (a)
220 (k)
66.000
33.000
20.000
11.000
6.600
380/220 (a)
Algeria 50 ± 1,5 220/127 (e)
220 (k)
380/220 (a)
220/127 (a)
10.000
5.500
6.600
380/220 (a)
Angola 50 380/220 (a)
220 (k)
380/220 (a) 380/220 (a)
Antigua and Barbuda 60 240 (k)
120 (k)
400/230 (a)
208/120 (a)
400/230 (a)
208/120 (a)
Argentina 50 ± 2 380/220 (a)
220 (k)
380/220 (a)
220 (k)
Armenia 50 ± 5 380/220 (a)
220 (k)
380/220 (a)
220 (k)
380/220 (a)
Azerbaijan 50 ± 0,1 208/120 (a)
240/120 (k)
208/120 (a)
240/120 (k)
Ethiopia 50 ± 2,5 220 (k) 380/220 (a)   15.000
380/220 (a)
Australia 50 ± 0,1 415/240 (a)
240 (k)
415/240 (a)
440/250 (a)
440 (m)
22.000
11.000
6.600
415/240
440/250
Bahrain 50 ± 0,1 415/240 (a)
240 (k)
415/240 (a)
240 (k)
11.000
415/240 (a)
240 (k)
Bangladesh 50 ± 2 410/220 (a)
220 (k)
410/220 (a) 11.000
410/220 (a)
Barbados 50 ± 6 230/115 (j)
115 (k)
230/115 (j)
200/115 (a)
220/115 (a)
230/400 (g)
230/155 (j)
Belgium 50 ± 5 230 (k)
230 (a)
3N, 400
230 (k)
230 (a)
3N, 400
15.000
11.000
10.000
6.600
400/230
Bolivia 50 ± 0,5 230 (k) 400/230 (a)
230 (k)
400/230 (a)
Botswana 50 ± 3 220 (k) 380/220 (a) 380/220 (a)
Brazil 60 220 (k, a)
127 (k, a)
380/220 (a)
220/127 (a)
13.800
11.200
380/220 (a)
200/127 (a)
Brunei 50 ± 2 230 230 68.000
11.000
230
Bulgaria 50 ± 0,1 220 240/220 1.000
690
380
Chile 50 ± 1 220 (k) 380/220 (a) 380/220 (a)
China 50 ± 0,5 220 (k) 380/220 (a)
220 (k)
380/220 (a)
220 (k)
Denmark 50 ± 1 400/230 (a) 400/230 (a) 400/230 (a)
Germany 50 ± 0,3 400/230 (a)
230 (k)
400/230 (a)
230 (k)
20.000
10.000
6.000
690/400
400/230
Dominica 50 230 (k) 400/230 (a) 400/230 (a)
Djibouti 50 400/230 (a) 400/230 (a)
Estonia 50 ± 1 380/220 (a)
220 (k)
380/220 (a)
220 (k)
380/220 (a)
Falkland Islands 50 ± 3 230 (k) 415/230 (a) 415/230 (a)
Fiji Islands 50 ± 2 415/240 (a)
240 (k)
415/240 (a)
240 (k)
11.000
415/240 (a)
Finland 50 ± 0,1 230 (k) 400/230 (a) 690/400 (a)
400/230 (a)
France 50 ± 1 400/230 (a)
230 (a)
400/230
690/400
20.000
10.000
400/230
Gambia 50 220 (k) 220/380 380
Georgia 50 ± 0,5 380/220 (a)
220 (k)
380/220 (a)
220 (k)
380/220 (a)
Ghana 50 ± 5 240/220 240/220 415/240 (a)
Gibraltar 50 ± 1 415/240 (a) 415/240 (a) 415/240 (a)
Granada 50 230 (k) 400/230 (a) 400/230 (a)
Greece 50 220 (k) 6.000
380/220 (a)
22.000
20.000
15.000
6.600
380/220
Great Britain
(except Northern Ireland)
50 ± 1 230 (k) 400/230 (a) 22.000
11.000
6.600
3.300
400/230 (a)
Great Britain
(including Northern Ireland)
50 ± 0,4 230 (k)
220 (k)
400/230 (a)
380/220 (a)
400/230 (a)
380/220 (a)
Hong Kong 50 ± 2 220 (k) 380/220 (a)
220 (k)
11.000
380/220 (a)
India 50 ± 1,5 440/250 (a)
230 (k)
440/250 (a)
230 (k)
11.000
440/250 (a)
400/230 (a)
Indonesia 50 ± 2 220 (k) 380/220 (a) 150.000
20.000
380/220 (a)
Iraq 50 220 (k) 380/220 (a) 11.000
6.600
3.000
380/220 (a)
Iran 50 ± 5 220 (k) 380/220 (a) 20.000
11.000
400/230 (a)
380/220 (a)
Ireland 50 ± 2 230 (k) 400/230 (a) 20.000
10.000
400/230 (a)
Iceland 50 ± 0,1 230 400/230 230/400
Israel 50 ± 0,2 400/230 (a)
230 (k)
400/230 (a)
230 (k)
22.000
12.600
6.300
400/230 (a)
Italy 50 ± 0,4 400/230 (a)
230 (k)
400/230 (a) 20.000
15.000
10.000
400/230 (a)
Jamaica 50 ± 1 220/110 (g) (j) 220/110 (g) (j) 4.000
2.300
220/110 (g)
Japan (east) + 0,1
- 0,3
200/100 (h) 200/100 (h)
(up to 50 kW)
140.000
60.000
20.000
6.000
200/100 (h)
Yemen 50 250 (k) 440/250 (a) 440/250 (a)
Jordan 50 380/220 (a)
400/230 (k)
380/220 (a) 400 (a)
Cambodia 50 ± 1 220 (k) 380/220 380/220
Cameroon 50 ± 1 220 (k) 220 (k) 380/220 (a)
Canada 60 ± 0,02 240/120 (j) 600/347 (a)
480 (f)
240 (f)
240/120 (j)
208/120 (a)
12.500/7.200
600/347 (a)
208/120
600 (f)
480 (f)
240 (f)
Cape Verde 220 220 380/220 (a)
Kazakhstan 50 380/220 (a)
220 (k)
220/127 (a)
127 (k)
380/220 (a)
220 (k)
380/220 (a)
Qatar 50 ± 0,1 415/240 (k) 415/240 (k) 11.000
415/240 (a)
Kenya 50 240 (k) 415/240 (a) 415/240 (a)
Kyrgyzstan 50 380/220 (a)
220 (k)
220/127 (a)
127 (k)
380/220 (a)
220 (k)
380/220 (a)
Colombia 60 ± 1 240/120 (g)
120 (k)
240/120 (g)
120 (k)
13.200
240/120 (g)
Congo 50 220 (k) 240/120 (j)
120 (k)
380/220 (a)
Korea (North) 60 +0,-5 220 (k) 380/220 (a) 13.600
6.800
Korea (South) 60 ± 0,2 220 (k) 380/220 (a) 380/220 (a)
Kuwait 50 ± 3 240 (k) 415/240 (a) 415/240 (a)
Laos 50 ± 8 380/220 (a) 380/220 (a) 380/220 (a)
Lesotho 220 (k) 380/220 (a) 380/220 (a)
Latvia 50 ± 0,4 380/220 (a)
220 (k)
380/220 (a)
220 (k)
380/220 (a)
Lebanon 50 220 (k) 380/220 (a) 380/220 (a)
Libya 50 230 (k)
127 (k)
400/230 (a)
220/127 (a)
230 (k)
127 (k)
400/230 (a)
220/127 (a)
Lithuania 50 ± 0,5 380/220 (a)
220 (k)
380/220 (a)
220 (k)
380/220 (a)
Luxembourg 50 ± 0,5 380/220 (a) 380/220 (a) 20.000
15.000
5.000
380/220
Madagascar 50 220/110 (k) 380/220 (a) 35.000
5.000
380/220
Malawi 50 ± 2,5 230 (k) 400 (a)
230 (k)
400 (a)
Malaysia 50 ± 1 415 (a)
240 (k)
415/240 (a) 415/240 (a)
Mali 50 220 (k)
127 (k)
380/220 (a)
220/127 (a)
220 (k)
127 (k)
380/220 (a)
220/127 (a)
Malta 50 ± 2 240 (k) 415/240 (a) 415/240 (a)
Morocco 50 ± 5 380/220 (a)
220/110 (a)
380/220 (a) 225.000
150.000
60.000
22.000
20.000
380/220
Martinique 50 127 (k) 220/127 (a)
127 (k)
220/127 (a)
Mauritania 50 ± 1 230 (k) 400/230 (a) 400/230 (a)
Mexico 60 ± 0,2 220/127 (a)
220 (k)
120 (l)
220/127 (a)
220 (k)
120 (l)
13.800
13.200
480/277 (a)
220/127 (b)
Moldova 50 380/220 (a)
220 (k)
220/127 (a)
127 (k)
380/220 (a)
220 (k)
380/220 (a)
Mozambique 50 380/220 (a) 380/220 (a) 10.000
6.000
380/220
Nepal 50 ± 1 220 (k) 440/220 (a)
220 (k)
11.000
440/220 (a)
New Zealand 50 ± 1,5 400/230 (e) (a)
230 (k)
460/230 (e)
400/230 (e) (a)
230 (k)
11.000
400/230 (a)
Netherlands 50 ± 0,4 400/230 (a)
230 (k)
400/230 (a) 25.000
20.000
12.000
10.000
400/230
Niger 50 ± 1 220 (k) 380/220 (a) 15.000
380/220 (a)
Nigeria 50 ± 1 230 (k)
220 (k)
400/230 (a)
380/220 (a)
15.000
11.000
400/230 (a)
380/220 (a)
Norway 50 ± 2 400/230 400/230 690
400/230
Oman 50 240 (k) 415/240 (a)
240 (k)
415/240 (a)
Austria 50 ± 0,1 230 (k) 400/230 (a) (b)
230 (k)
5.000
400/230 (a)
Pakistan 50 230 (k) 400/230 (a)
230 (k)
400/230 (a)
Papua New Guinea 50 ± 2 240 (k) 415/240 (a)
240 (k)
22.000
11.000
415/240 (a)
Paraguay 50 ± 0,5 220 (k) 380/220 (a)
220 (k)
22.000
380/220 (a)
Philippines 60 ± 0,16 220/110 (j) 13.800
4.160
2.400
220/110 (h)
13.800
4.160
2.400
440 (b)
220/110 (h)
Poland 50 ± 0,1 230 (k) 400/230 (a) 1.000
690/400
400/230 (a)
Portugal 50 ± 1 380/220 (a)
220 (k)
15.000
5.000
380/220 (a)
220 (k)
15.000
5.000
380/220 (a)
Rwanda 50 ± 1 220 (k) 380/220 (a) 15.000
6.600
380/220 (a)
Romania 50 ± 0,5 230 (k) 400/230 1.000
690/400
400/230
Russia 50 ± 0,2 380/220 (a)
220 (k)
380/220 (a)
220 (k)
380/220 (a)
Zambia 50 ± 2,5 220 (k) 380/220 (a) 380 (a)
Samoa 400/230
San Marino 50 ± 1 220 380 15,000
380
Santa Lucia 50 ± 3 240 (k) 415/240 (a) 11.000
415/240 (a)
Saudi Arabia 60 220/127 (a) 220/127 (a)
380/220 (a)
11.000
7.200
380/220 (a)
Sweden 50 ± 0,5 400/230 (a)
230 (k)
400/230 (a)
230 (k)
6.000
400/230 (a)
Switzerland 50 ± 2 400/230 (a) 400/230 (a) 20.000
10.000
3.000
1.000
400/230
Senegal 50 ± 5 220 (a)
127 (k)
380/220 (a)
220/127 (k)
90.000
30.000
6.600
Serbia and Montenegro 50 380/220 (a)
220 (k)
380/220 (a)
220 (k)
10.000
6.600
380/220 (a)
Seychelles 50 ± 1 400/230 (a) 400/230 (a) 11.000
400/230 (a)
Sierra Leone 50 ± 5 230 (k) 400/230 (a)
230 (k)
11.000
400
Zimbabwe 50 225 (k) 390/225 (a) 11.000
390/225 (a)
Singapore 50 400/230 (a)
230 (k)
400/230 (a) 22.000
6.600
400/230 (a)
Slovakia 50 ± 0,5 230 230 400/230
Slovenia 50 ± 0,1 220 (k) 380/220 (a) 10.000
6.600
380/220 (a)
Solomon Islands 50 ± 2 240 415/240 415/240
Somalia 50 220 (k)
110 (k)
440/220 (j)
220/110 (j)
440/220 (g)
220/110 (g)
Spain 50 ± 3 380/220 (a) (e)
220 (k)
220/127 (a)
127 (k)
380/220 (a)
220/127 (a) (e)
15.000
11.000
380/220 (a)
Sri Lanka 50 ± 2 230 (k) 400/230 (a)
230 (k)
11.000
400/230 (a)
South Africa 50 ± 2,5 433/250 (a)
400/230 (a)
380/220 (a)
220 (k)
11.000
6.600
3.300
433/250 (a)
400/230 (a)
380/220 (a)
11.000
6.600
3.300
500 (b)
380/220 (a)
Sudan 50 240 (k) 415/240 (a)
240 (k)
415/240 (a)
Swaziland 50 ± 2,5 230 (k) 400/230 (a)
230 (k)
11.000
400/230 (a)
Syria 50 220 (k)
115 (k)
380/220 (a)
220 (k)
200/115 (a)
380/220 (a)
Tajikistan 50 380/220 (a)
220 (k)
220/127 (a)
127 (k)
380/220 (a)
220 (k)
380/220 (a)
Tanzania 50 400/230 (a) 400/230 (a) 11.000
400/230 (a)
Thailand 50 220 (k) 380/220 (a)
220 (k)
380/220 (a)
Togo 50 220 (k) 380/220 (a) 20.000
5.500
380/220 (a)
Chad 50 ± 1 220 (k) 220 (k) 380/220 (a)
Czech Republic 50 ± 1 230 400/230 110.000
35.000
22.000
10.000
6.000
3.000
400/230
Tunisia 50 ± 2 380/220 (a)
220 (k)
380/220 (a)
220 (k)
30.000
15.000
Turkey 50 ± 1 380/220 (a) 380/220 (a) 15.000
6.300
380/220 (a)
Turkmenistan 50 380/220 (a)
220 (k)
220/127 (a)
127 (k)
380/220 (a)
220 (k)
380/220 (a)
Uganda + 0,1 240 (k) 415/240 (a) 11.000
415/240 (a)
Ukraine + 0,2 / - 1,5 380/220 (a)
220 (k)
380/220 (a)
220 (k)
380/220 (a)
220 (k)
Hungary 50 ± 5 220 220 380/220
Uruguay 50 ± 1 220 (b) (k) 220 (b) (k) 15.000
6.000
220 (b)
United Arab
Emirates
50 ± 1 220 (k) 415/240 (a)
380/220 (a)
220 (k)
6.600
415/210 (a)
380/220 (a)
United states of
America
Charlotte
(North Carolina)
60 ± 0,06 240/120 (j)
208/120 (a)
240/120 (j)
208/120 (a)
14.400
7.200
2.400
575 (f)
460 (f)
240 (f)
265/460 (a)
240/120 (j)
208/120 (a)
United states of
America
Detroit (Michigan)
60 ± 0,2 240/120 (j)
208/120 (a)
480 (f)
240/120 (h)
208/120 (a)
13.200
4.800
4.160
480 (f)
240/120 (h)
208/120 (a)
United States of
America
Los Angeles (California)
60 ± 0,2 240/120 (j) 4.800
240/120 (g)
4.800
240/120 (g)
United states of
America
Miami (Florida)
60 ± 0,3 240/120 (j)
208/120 (a)
240/120 (j)
240/120 (h)
208/120 (a)
13.200
2.400
480/277 (a)
240/120 (h)
United states of
America; new York
(New York)
60 240/120 (j)
208/120 (a)
240/120 (j)
240 (f)
208/120 (a)
12.470
4.160
480/277 (a)
480 (f)
United states of
America
Pittsburg
(Pennsylvania)
60 ± 0,03 240/120 (j) 460 (f)
240/120 (j)
230 (f)
208/120 (a)
13.200
11.500
2.400
460 (f)
230 (f)
208/120 (a)
United states of
America
Portland, Oregon
60 240/120 (j) 480/277 (a)
480 (f)
240/120 j)
240 f)
208/120 (a)
19.900
12.000
7.200
2.400
480/277 (a)
480 (f)
240 (f)
208/120 (a)
United states of
America
San Francisco
(California)
60 ± 0,08 240/120 (j) 480/277 (a)
240/120 (j)
20.800
12.000
4.160
480/277 (a)
240/120 (g)
United states of
America
Toledo (Ohio)
60 ± 0,08 240/120 (j)
208/120 (a)
480/277 (c)
240/120 (h)
208/120 (j)
12.470
7.200
4.800
4.160
480 (f)
480/277 (a)
208/120 (a)
Vietnam 50 ± 0,1 220 (k) 380/220 (a) 35.000
15.000
10.000
6.000
Belarus 50 380/220 (a)
220 (k)
220/127 (a)
127 (k)
380/220 (a)
220 (k)
380/220 (a)
Cyprus 50 ± 0,1 240 (k) 415/240 11.000
415/240

Fig. C1aVoltages of the local LV and HV networks with the associated circuit diagrams

Circuit diagrams

Fig.C1bAssigned circuit diagrams

Buyers in the residential and commercial building sector

The LV distribution network cable (underground cable or overhead line) is used to provide house connections and to supply a large number of consumers along its route.

The electricity load to be expected from LV distribution network cables is extrapolated using the number of customers to be connected and the average demand per consumer.

The two main limiting parameters of a LV distribution network cable are:

  • The maximum operating current that can be carried by the cross-section without limitation, and
  • the maximum cable length that does not exceed the normatively defined limit value for the voltage drop at the maximum operating current.

These restrictions mean that the number of consumers that the network operators want to connect to their LV distribution network is necessarily limited.

The following applies to the selection of LV systems mentioned in the section on low-voltage distribution networks:

230/400 V 3-phase: Typical maximum connection values ​​of loads that are connected to a LV distribution network cable at the voltages customary in Europe can be as follows[1] (please refer Fig.C2).

system Assumed maximum permissible
Electricity per house connection
kVA
120 V 1-phase, two conductors 60 A 7,2
120/240 V 1-phase, three conductors 60 A 14,4
120/208 V 3-phase, four conductors 60 A 22
220/380 V 3-phase, four conductors 120 A 79
230/400 V 3-phase, four conductors 120 A 83
240/415 V 3-phase, four conductors 120 A 86

Fig. C2Typical maximum permissible connection values ​​of loads that are connected to a LV distribution network cable

The techniques differ considerably between the individual network operators and standard values ​​cannot be given.

Factors to consider include:

  • The size of an existing distribution network to which the consumers are to be connected.
  • The total load that is already connected to the distribution network.
  • The location of the necessary new consumers in the distribution network, i.e. near the substation or near the end of a distribution network, etc.

In short, each case must be examined individually.

The connection values ​​listed above are suitable for all households and are sufficient for the systems of many public, commercial and similar buildings.

Small and medium-sized industrial customers (supplied with special LV cables / lines directly from a HV / LV transformer station of a network operator)

Small and medium-sized industrial consumers can also be adequately supplied with low voltage.

For consumers that exceed the maximum permissible limit value for a network connection via a LV feed, a special cable can normally be provided by the LV distributor (or the LV switchgear) in the network operator's transformer station.

In general, the maximum possible connection value that can be provided in this way is only limited by the available reserve capacity of the distribution transformers used in the network station.

However, the practice is often different:

  • Large loads (e.g.> 300 kVA) require correspondingly large cables / lines, so that this method can be economically unfavorable unless the center of the load is in the immediate vicinity of the transformer station.
  • Many network operators prefer to supply consumers with a connected load of more than 250 kVA (this output variable varies with the various network operators) with high voltage.

For these reasons, special LV supply cables are generally used for a connection value of 80 kVA to 250 kVA (with 230/400 V).

Consumers that are normally supplied with low voltage are:

  • Apartments
  • Shops and commercial buildings
  • Small factories, workshops and gas stations
  • Restaurants
  • Farms etc.

annotation

  1. ^ The values ​​shown in Fig. C2 are only indicative; They are arbitrarily based on maximum operating currents of 60 A for the first three systems, since smaller voltage drops are permissible at these lower voltages, with a specified normative limit value in percent. The second system group is again based arbitrarily on a maximum permissible operating current of 120 A.