Low-voltage consumers

The most-common LV supplies are within the range 120 V single phase to 240/415 V 3-phase 4-wires.

Loads up to 250 kVA can be supplied at LV, but power-supply organizations generally propose a MV service at load levels for which their LV networks are marginally adequate.

An international voltage standard for 3-phase 4-wire LV systems is recommended by the IEC 60038 to be 230/400 V

In Europe, the transition period on the voltage tolerance to “230V/400V + 10% / -10%” has been extended for another 5 years up to the year 2008.

Low-voltage consumers are, by definition, those consumers whose loads can be satisfactorily supplied from the low-voltage system in their locality.

The voltage of the local LV network may be 120/208 V or 240/415 V, i.e. the lower or upper extremes of the most common 3-phase levels in general use, or at some intermediate level, as shown in Figure C1 and C2.

Voltage of local LV networks

Fig. C1 – Voltage of local LV network and their associated circuit diagrams

Country	Frequency & tolerance (Hz & %)	Domestic (V)	Commercial (V)	Industrial (V)
Afghanistan	50	380/220 (a) 220 (k)	380/220 (a)	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) 120/208 (a)	400/230 (a) 120/208 (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)
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
Austria	50 ± 0.1	230 (k)	380/230 (a) (b) 230 (k)	5,000 380/220 (a)
Azerbaijan	50 ± 0.1	208/120 (a) 240/120 (k)	208/120 (a) 240/120 (k)
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)
Belarus	50	380/220 (a) 220 (k) 220/127 (a) 127 (k)	380/220 (a) 220 (k)	380/220 (a)
Belgium	50 ± 5	230 (k) 230 (a) 3N, 400	230 (k) 230 (a) 3N, 400	6,600 10,000 11,000 15,000
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 ± 3	220 (k,a) 127 (k,a)	220/380 (a) 127/220 (a)	69,000 23,200 13,800 11,200 220/380 (a) 127/220 (a)
Brunei	50 ± 2	230	230	11,000 68,000
Bulgaria	50 ± 0.1	220	220/240	1,000 690 380
Cambodia	50 ± 1	220 (k)	220/300	220/380
Cameroon	50 ± 1	220/260 (k)	220/260 (k)	220/380 (a)
Canada	60 ± 0.02	120/240 (j)	347/600 (a) 480 (f) 240 (f) 120/240 (j) 120/208 (a)	7,200/12,500 347/600 (a) 120/208 600 (f) 480 (f) 240 (f)
Cape Verde		220	220	380/400
Chad	50 ± 1	220 (k)	220 (k)	380/220 (a)
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)
Colombia	60 ± 1	120/240 (g) 120 (k)	120/240 (g) 120 (k)	13,200 120/240 (g)
Congo	50	220 (k)	240/120 (j) 120 (k)	380/220 (a)
Croatia	50	400/230 (a) 230 (k)	400/230 (a) 230 (k)	400/230 (a)
Cyprus	50 ± 0.1	240 (k)	415/240	11,000 415/240
Czech Republic	50 ± 1	230	500 230/400	400,000 220,000 110,000 35,000 22,000 10,000 6,000 3,000
Denmark	50 ± 1	400/230 (a)	400/230 (a)	400/230 (a)
Djibouti	50		400/230 (a)	400/230 (a)
Dominica	50	230 (k)	400/230 (a)	400/230 (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)
Estonia	50 ± 1	380/220 (a) 220 (k)	380/220 (a) 220 (k)	380/220 (a)
Ethiopia	50 ± 2.5	220 (k)	380/231 (a)	15 000 380/231 (a)
Falkland Islands	50 ± 3	230 (k)	415/230 (a)	415/230 (a)
Fidji 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)	400/230 690/400 590/100	20,000 10,000 230/400
Gambia	50	220 (k)	220/380	380
Georgia	50 ± 0.5	380/220 (a) 220 (k)	380/220 (a) 220 (k)	380/220 (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
Ghana	50 ± 5	220/240	220/240	415/240 (a)
Gibraltar	50 ± 1	415/240 (a)	415/240 (a)	415/240 (a)
Greece	50	220 (k) 230	6,000 380/220 (a)	22,000 20,000 15,000 6,600
Granada	50	230 (k)	400/230 (a)	400/230 (a)
Hong Kong	50 ± 2	220 (k)	380/220 (a) 220 (k)	11,000 386/220 (a)
Hungary	50 ± 5	220	220	220/380
Iceland	50 ± 0.1	230	230/400	230/400
India	50 ± 1.5	440/250 (a) 230 (k)	440/250 (a) 230 (k)	11,000 400/230 (a) 440/250 (a)
Indonesia	50 ± 2	220 (k)	380/220 (a)	150,000 20,000 380/220 (a)
Iran	50 ± 5	220 (k)	380/220 (a)	20,000 11,000 400/231 (a) 380/220 (a)
Iraq	50	220 (k)	380/220 (a)	11,000 6,600 3,000 380/220 (a)
Ireland	50 ± 2	230 (k)	400/230 (a)	20,000 10,000 400/230 (a)
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)
Jordan	50	380/220 (a) 400/230 (k)	380/220 (a)	400 (a)
Kazakhstan	50	380/220 (a) 220 (k) 220/127 (a) 127 (k)	380/220 (a) 220 (k)	380/220 (a)
Kenya	50	240 (k)	415/240 (a)	415/240 (a)
Kirghizia	50	380/220 (a) 220 (k) 220/127 (a) 127 (k)	380/220 (a) 220 (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
Macedonia	50	380/220 (a) 220 (k)	380/220 (a) 220 (k)	10,000 6,600 380/220 (a)
Madagascar	50	220/110 (k)	380/220 (a)	35,000 5,000 380/220
Malaysia	50 ± 1	240 (k) 415 (a)	415/240 (a)	415/240 (a)
Malawi	50 ± 2.5	230 (k)	400 (a) 230 (k)	400 (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)
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	127/220 (a) 120/240 (j)	127/220 (a) 120/240 (j)	4,160 13,800 23,000 34,500 277/480 (a) 127/220 (b)
Moldavia	50	380/220 (a) 220 (k) 220/127 (a) 127 (k)	380/220 (a) 220 (k)	380/220 (a)
Morocco	50 ± 5	380/220 (a)	380/220 (a)	225,000
		220/110 (a)		150,000 60,000 22,000 20,000
Mozambique	50	380/220 (a)	380/220 (a)	6,000 10,000
Nepal	50 ± 1	220 (k)	440/220 (a) 220 (k)	11,000 440/220 (a)
Netherlands	50 ± 0.4	230/400 (a) 230 (k)	230/400 (a)	25,000 20,000 12,000 10,000 230/400
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)
Niger	50 ± 1	230 (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	230/400	230/400	230/400 690
Oman	50	240 (k)	415/240 (a) 240 (k)	415/240 (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 (Rep of the)	60 ± 0.16	110/220 (j)	13,800 4,160 2,400 110/220 (h)	13,800 4,160 2,400 440 (b) 110/220 (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)
Qatar	50 ± 0.1	415/240 (k)	415/240 (a)	11,000 415/240 (a)
Romania	50 ± 0.5	220 (k) 220/380 (a)	220/380 (a)	20,000 10,000 6,000 220/380 (a)
Russia	50 ± 0.2	380/220 (a) 220 (k)	380/220 (a) 220 (k)	380/220 (a)
Rwanda	50 ± 1	220 (k)	380/220 (a)	15,000 6,600 380/220 (a)
Saint Lucia	50 ± 3	240 (k)	415/240 (a)	11,000 415/240 (a)
Samoa		400/230
San Marino	50 ± 1	230/220	380	15,000 380
Saudi Arabia	60	220/127 (a)	220/127 (a) 380/220 (a)	11,000 7,200 380/220 (a)
The Solomon Islands	50 ± 2	240	415/240	415/240
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
Singapore	50	400/230 (a) 230 (k)	400/230 (a)	22,000 6,600 400/230 (a)
Slovakia	50 ± 0.5	230	230	230/400
Slovenia	50 ± 0.1	220 (k)	380/220 (a)	10,000 6,600 380/220 (a)
Somalia	50	230 (k) 220 (k) 110 (k)	440/220 (j) 220/110 (j) 230 (k)	440/220 (g) 220/110 (g)
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)
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)
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)
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 1,000 690/500
Syria	50	220 (k) 115 (k)	380/220 (a) 220 (k) 200/115 (a)	380/220 (a)
Tadzhikistan	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)
Tunisia	50 ± 2	380/220 (a) 220 (k)	380/220 (a) 220 (k)	30,000 15,000
				10,000 380/220 (a)
Turkmenistan	50	380/220 (a) 220 (k) 220/127 (a) 127 (k)	380/220 (a) 220 (k)	380/220 (a)
Turkey	50 ± 1	380/220 (a)	380/220 (a)	15,000 6,300 380/220 (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)
United Arab Emirates	50 ± 1	220 (k)	415/240 (a) 380/220 (a) 220 (k)	6,600 415/210 (a) 380/220 (a)
United Kingdom (except Northern Ireland)	50 ± 1	230 (k)	400/230 (a)	22,000 11,000 6,600 3,300 400/230 (a)
United Kingdom (Including Northern Ireland)	50 ± 0.4	230 (k) 220 (k)	400/230 (a) 380/220 (a)	400/230 (a) 380/220 (a)
United States of America Charlotte (North Carolina)	60 ± 0.06	120/240 (j) 120/208 (a)	265/460 (a) 120/240 (j) 120/208 (a)	14,400 7,200 2,400 575 (f) 460 (f) 240 (f) 265/460 (a) 120/240 (j) 120/208 (a)
United States of America Detroit (Michigan)	60 ± 0.2	120/240 (j) 120/208 (a)	480 (f) 120/240 (h) 120/208 (a)	13,200 4,800 4,160 480 (f) 120/240 (h) 120/208 (a)
United States of America Los Angeles (California)	60 ± 0.2	120/240 (j)	4,800 120/240 (g)	4,800 120/240 (g)
United States of America Miami (Florida)	60 ± 0.3	120/240 (j) 120/208 (a)	120/240 (j) 120/240 (h) 120/208 (a)	13,200 2,400 480/277 (a) 120/240 (h)
United States of America New York (New York)	60	120/240 (j) 120/208 (a)	120/240 (j) 120/208 (a) 240 (f)	12,470 4,160 277/480 (a) 480 (f)
United States of America Pittsburg (Pennsylvania)	60 ± 0.03	120/240 (j)	265/460 (a) 120/240 (j) 120/208 (a) 460 (f) 230 (f)	13,200 11,500 2,400 265/460 (a) 120/208 (a) 460 (f) 230 (f)
United States of America Portland (Oregon)	60	120/240 (j)	227/480 (a) 120/240 (j) 120/208 (a) 480 (f) 240 (f)	19,900 12,000 7,200 2,400 277/480 (a) 120/208 (a) 480 (f) 240 (f)
United States of America San Francisco (California)	60 ± 0.08	120/240 (j)	277/480 (a) 120/240 (j)	20,800 12,000 4,160 277/480 (a) 120/240 (g)
United States of America Toledo (Ohio)	60 ± 0.08	120/240 (j) 120/208 (a)	277/480 (c) 120/240(h) 120/208 (j)	12,470 7,200 4,800 4,160 480 (f) 277/480 (a) 120/208 (a)
Uruguay	50 ± 1	220 (b) (k)	220 (b) (k)	15,000 6,000 220 (b)
Vietnam	50 ± 0.1	220 (k)	380/220 (a)	35,000 15,000 10,000 6,000
Yemen	50	250 (k)	440/250 (a)	440/250 (a)
Zambia	50 ± 2.5	220 (k)	380/220 (a)	380 (a)
Zimbabwe	50	225 (k)	390/225 (a)	11,000 390/225 (a)

Circuit diagrams

Fig. C2 – Associated circuit diagrams

• 

  [a] Three-phase star; Four-wire: Earthed neutral

• 

  [b] Three-phase star: Three-wire

• 

  [c] Three-phase star; Three-wire:Earthed neutral

• 

  [d] Three-phase star; Four-wire:Non-earthed neutral

• 

  [e] Two-phase star;Three-wire: Earthed neutral

• 

  [f] Three-phase delta: Three-wire

• 

  [g] Three-phase delta; Four-wire: Earthed mid point of one phase

• 

  [h] Three-phase open delta; Four-wire: Earthed mid point of one phase

• 

  [i] Three-phase open delta: Earthed junction of phases

• 

  [j] Single-phase; Three-wire: Earthed mid point

• 

  [k] Single-phase; Two-wire: Earthed end of phase

• 

  [l] Single-phase; Two-wire Unearthed

• 

  [m] Single-wire: Earthed return (swer)

• 

  [n] DC: Three-wire: Unearthed

Residential and commercial consumers

The function of a LV “mains” distributor is to provide service connections (underground cable or overhead line) to a number of consumers along its route.

The current-rating requirements of distributors are estimated from the number of consumers to be connected and an average demand per consumer.

The two principal limiting parameters of a distributor are:

• The maximum current which it is capable of carrying indefinitely, and
• The maximum length of cable which, when carrying its maximum current, will not exceed the statutory voltage-drop limit

These constraints mean that the magnitude of loads which utilities are willing to connect to their LV distribution mains, is necessarily restricted.

For the range of LV systems mentioned in Voltage of local LV networks viz: 120 V single phase to 240/415 V 3-phase, typical maximum permitted loads connected to a LV distributor might be (see Fig. C3):

Fig. C3 – Typical maximum permitted loads connected to a LV distributor

System		Assumed max. permitted current per consumer service	kVA
120 V	1-phase 2-wire	60 A	7.2
120/240 V	1-phase 3-wire	60 A	14.4
120/208 V	3-phase 4-wire	60 A	22
220/380 V	3-phase 4-wire	120 A	80
230/400 V	3-phase 4-wire	120 A	83
240/415 V	3-phase 4-wire	120 A	86

Practices vary considerably from one power supply organization to another, and no “standardized” values can be given.

Factors to be considered include:

• The size of an existing distribution network to which the new load is to be connected
• The total load already connected to the distribution network
• The location along the distribution network of the proposed new load, i.e. close to the substation, or near the remote end of the distribution network, etc

In short, each case must be examined individually.

The load levels listed above are adequate for all normal residential consumers, and will be sufficient for the installations of many administrative, commercial and similar buildings.

Medium-size and small industrial consumers (with dedicated LV lines direct from a utility supply MV/LV substation)

Medium and small industrial consumers can also be satisfactorily supplied at low-voltage.

For loads which exceed the maximum permitted limit for a service from a distributor, a dedicated cable can usually be provided from the LV distribution fuse- (or switch-) board, in the power utility substation.

Generaly, the upper load limit which can be supplied by this means is restricted only by the available spare transformer capacity in the substation.

In practice, however:

• Large loads (e.g. > 300 kVA) require correspondingly large cables, so that, unless the load centre is close to the substation, this method can be economically unfavourable
• Many utilities prefer to supply loads exceeding 200 kVA (this figure varies with different suppliers) at medium voltage

For these reasons, dedicated supply lines at LV are generally applied (at 220/380 V to 240/415 V) to a load range of 80 kVA to 250 kVA.

Consumers normally supplied at low voltage include:

• Residential dwellings
• Shops and commercial buildings
• Small factories, workshops and filling stations
• Restaurants
• Farms, etc