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  1. Guide & Knowledge
  2. Guide
  3. Cable cross-section
Kabelquerschnitt-messen

Calculate cable cross-section

All important formulas and tables, including calculator and PDF data sheets of the tables for download.

Table of contents

  • What is the cable cross-section?
  • Why is the cable cross-section so important?
  • How is the cable cross-section / conductor cross-section calculated?
  • How is the cable cross-section calculated in relation to the voltage?
  • How is the cable cross-section calculated in relation to the amperage?
  • How is the cable cross-section calculated in relation to the power?
  • Excursus: Cable cross-section for walboxes and PV systems
  • Cable cross-section for power cables, underground cables and domestic installations
  • Which fuse for which cable cross-section?
  • Further questions on the subject of cable cross-section

Reliable and adequately dimensioned cabling is the be-all and end-all for power supply in the private and industrial sectors. After all, if you cut corners with the wiring and choose a cable cross-section that is too small for the power of the connected loads, premature wear of the wires, a short circuit or a cable fire can result in high consequential costs.

Under certain circumstances, it can also cause problems with the insurance company. Our guide contains useful tips and clarifies the most important questions about cable cross-sections.

What is the cable cross-section?

The cable cross-section or wire cross-section is the cross-sectional area of the metal conductors. As a rule of thumb, the larger the cross-sectional area of the conductors in a cable, the greater the current carrying capacity. The cable cross-section is given in mm² and thus provides information about the surface area of the round cable section. Important: The cable cross-section is not the same as the diameter of the cable, as this is a length measurement.

Cross-sectional area of the conductor: A distinction is made between the geometrically defined nominal cross-section and the conductive cross-section, which is derived from the electrical resistance. The nominal cross-section is specified in square millimetres. However, it is not defined as a geometric cross-section, but as the electrically effective cross-section of the conductor at 20°C. Compliance with the nominal cross-section must be verified during the final inspection of the product and is also one of the focal points of the self-checks in the ongoing production inspections.

A certain maximum resistance is assigned to the nominal cross-section, within which the conductor structure is also specified. As a rule, the cross-section is specified in mm². However, for certain types of wires and cables, which are always made up of single-wire conductors (telecommunications cables), the conductor diameter is used for labelling or description purposes.

Here you will find all the diameters of the individual cable cross-sections clearly presented in a table:

Cable cross-sections standardised in accordance with IEC 60228 and VDE 0295 Diameter of the conductor
 0.25 mm² ~0.56mm
 0.34 mm² ~0.66mm
 0.5 mm² ~0.80mm
 0.75 mm²  ~0.98 mm
 1 mm²  ~1.13 mm
 1.5 mm²  ~1.38 mm
 2.5 mm²  ~1.78 mm
 4 mm²  ~2.26 mm
 6 mm²  ~2.76 mm
 10 mm²  ~3.57 mm
 16 mm²  ~4.51 mm
 25 mm²  ~5.64 mm
 35 mm²  ~6.68 mm
 50 mm²  ~7.98 mm
 70 mm²  ~9.44 mm
 95 mm²  ~11 mm
 120 mm²  ~12.40 mm
 150 mm²  ~13.82 mm
 185 mm²  ~15.35 mm
 240 mm²  ~17.48 mm
 300 mm²  ~19.54 mm
 400 mm²  ~22.57 mm
 500 mm²  ~25.23 mm
 630 mm²  ~28.32 mm
 800 mm²  ~31.91 mm
 1000 mm²  ~35.68 mm

Download table

What standards are there for cable cross-sections?

The internationally recognised standard IEC 6022 refers to the conductor cross-section of insulated cables and is equivalent to the cable cross-section DIN standard DIN EN 60228 and the conductor cross-section standard VDE 0295.

Normen für Leitungsquerschnitte_EN

What does the required cable cross-section depend on?

As a rule of thumb, the more power required, the larger the cable cross-section.


Why is the cable cross-section so important?

One of the most frequently asked questions in electrical installation is: Which values have an influence on the cable cross-section to be selected? In addition to the voltage, the amount of current to be conducted and the power, the length of the cable must also be taken into account when selecting a suitable cable cross-section.

You can find more information on the topic of current/voltage in our guide article "How is electrical voltage measured and calculated?".

How do I recognise the cable cross-section?

A wire gauge is suitable for measuring the cable cross-section of a wire. You can also use a caliper gauge to determine the cable cross-section. For multi-core cables with fine strands, it is advisable to measure the cable cross-section with insulation so that accidental compression does not falsify the measurement.

Please also bear in mind that the diameter of the cables including insulation varies from manufacturer to manufacturer. If in doubt, it is therefore advisable to determine the cable cross-section of the single core cables. With some cables, the cable cross-section can also be recognised by the imprint on the sheath.

Einzeladern-Ratgeberbox
By the metre, in stock
Single wires

H05V-K, H07V-K, H05Z-K, silicone, multinorm single cores and much more.

TO THE PRODUCTS

What happens if the cable cross-section is too small or too large?

A large cable cross-section primarily results in higher costs and, as it is less flexible, you can expect the cable to be more complex to lay.
The longer and thinner a wire is, the greater the risk of heat build-up, which in turn increases the resistance of the conductor. In the worst case, this can melt the insulation and cause a fire. For this reason, cable cross-sections in all electrical systems are always selected larger the longer the cable is. Voltage drops are compensated for by using larger cross-sections, thus ensuring that a voltage of 230V is present in the cable network, for example.

Kabelquerschnitt-messen

Is the cable cross-section the same as the cable diameter?

The cable cross-section is an area measurement (in mm²) and the cable diameter is a length measurement (in mm). These can be calculated using simple formulae. In electrical engineering in particular, it is sometimes important to calculate the cable diameter in cable cross-section.

Calculate the cable cross-section from the cable diameter using the formula:

A=r² * π =  d² * π/4   

or

Berechnung des Kabelquerschnitt aus den Leitungsdurchmesser

Calculate the cable diameter from the cable cross-section using the formula

d=2 * √A/ π  =  2 * r

or

Berechnung des Kabeldurchmesser aus den Kabelquerschnitt 

Note: the thickness of the insulation and the separating air for stranded wires musthave atotal diameter that is around 14 % larger than that of a solid wire due to the individual wires lying next to each other.


Kabel-und-Leitungen-Ratgeberbox

Free cutting from 1 metre

Cables & wires

Ölflex control cables, data cables, single cores, rubber cables and much more.

TO THE PRODUCTS

Formula for calculating the cable cross-section: 

 A = (2 x I x L) / (y x Ua x U)

How is the cable cross-section / conductor cross-section calculated?

A frequently asked question is: What values are needed to calculate the cable cross-section? In fact, you only need a few parameters. To calculate the cable cross-section (A), e.g. for direct current, you need the following values: current in amperes (I), length of the cable (L), voltage drop (Ua), as well as the specific conductance Kappa copper (y) and the voltage (U). The complete formula for calculating the cable cross-section is as follows:

A = (2 x I x L) / (y x Ua x U)

No time to do the maths? Instead of calculating the optimum cable cross-section using this rule of thumb, you can also consult our cable cross-section table.

Cable cross-sections standardised in accordance with VDE 0295 for 12 V DC applications Maximum current in amperes
1 mm² 11A
1.5 mm² 15A
2.5 mm² 20A
4 mm² 25A
6 mm² 33A
10 mm² 45A
16 mm² 61A
25 mm² 83A
35 mm² 103A
50 mm² 132A
70 mm² 165A
95 mm² 197A
120 mm²  235 A

Download cable cross-section table

If you use three-phase current, you can also calculate the cable cross-section. In addition to the voltage, you also need information on the efficiency and power. As with AC applications, the design of the cable cross-section must be increased with increasing voltage and power.

Calculate cable cross-section, power and amperage

Cable cross-section calculation (three-phase current / alternating current)

Calculate the cable cross-section (three-phase current / alternating current) quickly and easily.

  • Conductor material:
  • Cable length: (in metres)
    m
  • Mains form:
  • Mains voltage: (in volts - value can be changed)
    V img
  • Power or current: (in kilowatts or amperes)
    kW
    OR
    A
  • Cos φ: (value can be changed)
    φ img
  • Voltage drop: (in % - value can be changed)
    % img
  • Cable cross section of the individual wire:

  • Available cross sections:
  • Info:

Calculate the cable cross-section (three-phase current / alternating current) quickly and easily.

Current-carrying capacity of cables and lines This information on current-carrying capacity up to a cross-section of 35 mm² refers to multi-core cables laid permanently in a building, e.g. in an installation pipe, with max. 3 loaded outer conductors at an ambient temperature of 25°C. The specifications for cross-sections of 50 mm² and ascending refer to multi-core cables laid in the ground with max. 3 loaded outer conductors at an ambient temperature of 20°C.

  • Formula for calculation - three-phase current A = 1,732 * L * ((kW * 1000) / (U * 1,732)) * cos(y * Ua)
  • Formula for calculation - alternating current A = 2 * L * I * cos φy * Ua
  • A = Conductor cross-section of the single wire in mm²
  • L = Single conductor length in metres
  • I = Conductor current (current of the single core) in A/span>
  • cos φ = Efficiency - inductive / capacitive load (in practice 0.9 to 1)
  • y = Conductivity of copper (56) or aluminium (37)
  • Ua = Voltage drop in volts
  • 1,732 = Interlinking factor (√ 3)
  • U = Mains voltage in volts
Calculate power (three-phase current / alternating current)

Calculate the power (three-phase current / alternating current) quickly and easily.

  • Mains form:
  • Voltage: (in volts)
    V img
  • Amperage: (in amperes)
    A
  • Power result =

  • Formula for calculation - three-phase current P = U * I * 1,73
  • Formula for calculation - alternating current P = U * I
  • P = Power in watts
  • U = Voltage in volts
  • I = Current in amperes
Calculate current (three-phase current / alternating current)

Calculate the current strength (three-phase current / alternating current) quickly and easily.

  • Mains form:
  • Voltage: (in volts)
    V img
  • Amperage: (in amperes)
    W
  • Current result =

  • Formula for calculation - three-phase current I = P / (U*1,73)
  • Formula for calculation - alternating current I = P / U
  • P = Power in watts
  • U = Voltage in volts
  • I = Current in amperes
All statements without guarantee!

Cable calculation based on voltage drop

  • When selecting the cable, it is important to consider not only the possible current carrying capacity depending on the type of installation, but also the voltage drop that occurs during normal operation.
  • Permissible voltage drops are, for example, 0.5 % from the house connection box (HAK) to the meter point and max. 3 % from the meter point to the last consumer.
  • Voltage drop means that the desired 230/400 V, for example, no longer arrive at the end of the line during normal operation, but less according to the calculation.
  • Voltage drop also means power loss via the line. This is power that is missing at the end of the line, but is recorded by the meter and therefore also represents a cost factor.
  • The voltage drop depends on the cable length, the cable cross-section, the mains voltage, e.g. 230/400 V or, in the case of low voltages, e.g. 12/24 V DC, and the current that must flow through the cable.
  • We provide our calculator by entering the current in amperes (A) or alternatively by entering the power in kilowatts (KW) if the current specification is unknown. The last factor that plays a role is the cos φ. This is the ratio between apparent power, active power and reactive power. If no information is available, you should assume a factor of 0.9 - 1.
  • After the calculation, an indication appears in qmm, this is purely arithmetical, when selecting, the next higher value must be selected accordingly.

To calculate the cable cross-section in relation to the voltage, use the following formula for AC current (230V): 

A = 2 * L * I * cos φ / y * Ua

How is the cable cross-section calculated in relation to the voltage?

This is how you calculate the cross-section:
To calculate the cable cross-section in relation to the voltage, use the formula for alternating current (230V):

A = 2 * L * I * cos φ / y * Ua

Again,A stands for the cable cross-section in mm², L for the simple cable length in metres, I indicates the current of the single core cables in amperes and cos φ indicates the efficiency, which is usually between 0.9 and 1. The y stands for the conductivity, which is 58 in the case of copper and 37 in the case of aluminium. The parameter Ua characterises the voltage drop in volts.

Using this method, you can easily calculate how large the cable cross-section should be, e.g. for a 230 volt domestic power line, or the cable cross-section for low voltage.

Maximum power with a cable length of up to 10 metres Recommended cable cross-section at 230 V in mm² Recommended cable cross-section at 400 V in mm²
1,000 watts 2.5 mm² 1.5 mm² 
1,200 watts  2.5 mm²  1.5 mm² 
1,500 watts  2.5 mm²  1.5 mm² 
1,800 watts  2.5 mm²  1.5 mm² 
2,100 watts  2.5 mm²  1.5 mm² 
3,500 watts 2.5 mm² 1.5 mm²

Download table

Product recommendations

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7-wire
1119107 LAPP-Kabel ÖLFLEX Classic 110 7G0.75 mm² AD 7.3 mm Rated voltage Uo/U 300V/500V
1119107 LAPP-Kabel ÖLFLEX Classic 110 7G0.75 mm² AD 7.3 mm Rated voltage Uo/U 300V/500V
Test voltage 4000V Minimum bending radius moving 15.0xouter diameter Minimum bendi...
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PVC cable
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18104 HELUKABEL LIYY 2x0.75 mm² Data line AD 5.3 mm
18104 HELUKABEL LIYY 2x0.75 mm² Data line AD 5.3 mm
LIYY data lines / 2 core, cross-section 0.14 to 1.5mm²
7 variations
from €0.30
plus shipping costs excl. VAT

What cable cross-section for 12V?

To calculate the cable cross-section (A) for 12V consumers, you can use the following formula:

A = (I * 0.0175 * L * 2) / (fk * U).

I = max. current in amperes
L = cable length
fk = loss factor in per cent divided by 100 (e.g. fk 2% = 0.02)
U = voltage
0.0175 gives the specific resistance of copper in ohms x mm² / m.

If a standardised cable cross-section is to be used for 12V consumers, refer to the following table. Here you can also see how large the 12V cable cross-section should be for the respective power in amperes.

Example: A=(9.1A x 0.0175 x 1.5m x 2) / (0.02 x 12V)

Cable cross-sections standardised according to IEC 60228 and VDE 0295 for 12V applications Maximum current in amperes
1 mm² 11A
1.5 mm² 15A
2.5 mm² 20A
4 mm² 25A
6 mm² 33A
10 mm² 45A
16 mm² 61A
25 mm² 83A
35 mm² 103A
50 mm² 132A
70 mm² 165A
95 mm² 197A
120 mm²  235 A

Download table

The cable cross-section of your vehicle's 12V electrical system must also be designed for the high output of a starter battery.
For 100 A at 12V, it is recommended to use wires with a cable cross-section of at least 35 mm².

Which cable cross-section for 24V?

A sufficient cable cross-section is not only important for 230V consumers in the home. It is also recommended in motorhomes or when using LED lighting with 24V. The following table lists the recommended cable cross-sections for a cable length of 3 metres and an output of up to 1000 watts.

Cable cross-sections for 24V applications with 3 metre cable length Power in watts
1.5 mm² 100 Watt
3 mm² 200 Watt
4.5 mm² 300 watts
6 mm² 400 watts
7.5 mm² 500 watts
9 mm² 600 watts
10.5 mm² 700 watts
12 mm² 800 watts
13.5 mm² 900 watts
15 mm² 1,000 watts

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What cable cross-section for 230V?

To calculate the cable cross-section for 230V, use the following formula:

A = 2 * L * I * cos φ / y * Ua.

A = cable cross-section in mm²
L = cable length in metres
I = conductor current in amperes
cos φ = efficiency (between 0.9 and 1)
y = Conductivity (copper 58, aluminium 37)
Ua = voltage drop in volts.



Cable cross-sections for 230V applications with a cable length of 10 metres Power in kW Current in amperes
1.5 mm² 3.5 kW  ~15A
2.5 mm²  5.5 kW   ~23A
4.0 mm²  6.5 kW   ~28A
6.0 mm²  7.5 kW   ~32A
10.0 mm²  12 kW   ~52A
16 mm²  16 kW   ~65A
25 mm²  22 kW   ~95A

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What cross-section for 400V?

To calculate the cable cross-section on a 3-phase 400V wire, you need the following formula:

A = 1.732 * L * I * cos φ / y * ua * U

or

A = √3* L * I * cos φ / y * ua * U

A = Cable cross-section single core cables in mm²
L = cable length in metres
I = conductor current in amperes
cos φ = efficiency (between 0.9 and 1)
y = Conductivity (copper 58, aluminium 37)
ua = voltage drop in %
U = Mains voltage in volts

1.732 (or √ 3) = Interlinking factor (ratio of the electrical voltage between two neighbouring outer conductors)



Cable cross-sections for 400V applications with a cable length of 10 metres Power in kW Current in amperes
1.5 mm²  3.5 kW  ~5A
1.5 mm²  4.5 kW   ~6.5A
1.5 mm²  5.5 kW   ~8A
1.5 mm²  6.5 kW   ~9.4A
1.5 mm²  7.5 kW  ~11A
2.5 mm²  12 kW   ~17.3A
4 mm²  16 kW   ~23A
6 mm²  22 kW   ~32A

Download table
Formula Cable cross-section for three-phase current:
A= √3 * L * I * cos φ / y * ua * U

How is the cable cross-section calculated in relation to the amperage?

The current carrying capacity, or maximum current that is permissible for a cable cross-section, can be calculated for direct current, alternating current and three-phase current applications. You will need the following formulae for the calculation:

Formula cable cross-section for three-phase current: A= √3 * L * I * cos φ / y * ua * U

If you insert the values accordingly, you get the value for the cable cross-section (A) in mm², which is recommended for the respective current in amperes or power in watts.

Formula cable cross-section for direct current: A= 2 * L * I / y * ua * U

Cable cross-sections for 24V applications with 3 metre cable length Power in watts Current in amperes
1.5 mm²  100 Watt 4.2A
3 mm²  200 Watt  8.3A
4.5 mm²  300 Watt  12.5A
6 mm²  400 Watt  16.7A
7.5 mm²  500 Watt 20.8A
9 mm²  600 Watt  25A
10.5 mm²  700 Watt  29.2A
12 mm²  800 Watt  33.3A
13.5 mm²  900 Watt  37.5A 
15 mm²  1,000 watts 41.7A

The following table shows which cable cross-section you should select depending on the current in amperes, which specifies the load capacity of wires with rated voltages up to 1000V in accordance with VDE 0298-4.

Cable cross-section in mm² Single-core and  heat-resistant wires laid freely in the air. Insulated with rubber or PVC Multicore and heat-resistant wires laid on or on surfaces (excluding domestic or hand-held appliances). Insulated with rubber or PVC
0.75 mm²  15A 12A
1 mm²  19A 15A
1.5 mm²  24A  18A
2.5 mm²  32A  26A
4 mm²  42A 34A
6 mm²  54A  44A
10 mm²  73A  61A
16 mm²  98A  82A
25 mm²  129A  108A 
35 mm²  158A 135A
50 mm²  198A  168A 
70 mm² 245A 207A
95 mm² 292A 250A
120 mm² 344A 292A

Download table

Which cable cross-section do you need to select for high voltage or three-phase current?

What cable cross-section do you need to select for heavy current or three-phase current? In principle, the recommended cable cross-section increases with increasing current in amperes.

How many amperes for which cross-section at 400V?

From 5 amps, wires with 1.5 mm² are recommended.
From 16 amps, wires with 1.5 mm² are recommended.
From 17.3 amps, wires with 2.5 mm² are recommended.
From 20 amps, wires with 2.5 mm² are recommended.
From 23 amps, wires with 4 mm² are recommended.
From 32 amps, a 6 mm² wire is recommended.

How many amps for which cross-section at 230V?

From 10 amps, wires with 2.5 mm² are recommended.
From 16 amps, wires with 2.5 mm² are recommended.
From 32 amps, wires with 4 mm² are recommended.
From 50 amps, wires with 10 mm² are recommended.
From 63 amps, a 16 mm² wire is recommended.
From 100 amps, a 35 mm² wire is recommended.
From 125 amps, wires with 50 mm² are recommended.
From 180 amps, wires with 95 mm² are recommended.
From 230 amps, we recommend using wires with 120 mm².


H07RN-F-1x1-5mm-Kabelquerschnitt

H07BQ-F 1x1,5mm²

H07RN-F-1x16mm-Kabelquerschnitt

H07BQ-F 1x16mm²

H07RN-F-1x95mm-Kabelquerschnitt

H07BQ-F 1x95mm²

Geflechtschläuche-Ratgeberbox

By the metre from stock

Rubber cable

H05RN-F, H07RN-F, H05BQ-F, H07BQ-F, NSGAFÖU, NSSHÖU, H07RN8-F uvm.

TO THE PRODUCTS

For the cable cross-section calculation using known dc power, use this formula:

A=2 * L * I / γ * ua * U


How is the cable cross-section calculated in relation to the power?

You can also use the formulae already mentioned to calculate the cable cross-section required for the respective power. It is particularly easy to determine the cable cross-section if you know the power (in watts) of the consumer.

To calculate the cable cross-section using known DC power, use this formula:

A=2 * L * I / γ * ua * U

A = Cable cross-section of single core cables in mm²
L = cable length in metres
I = conductor current in amperes
y = Conductivity (copper 58, aluminium 37)
ua = Voltage drop in %
U = Mains voltage in volts

Formula for calculating the cable cross-section based on the three-phase power:

A = 1.732 * L * I * cos φ / y * ua * U

or

A = √3* L * I * cos φ / y * ua * U

A = Cable cross-section single core cables in mm²
L = cable length in metres
I = conductor current in amperes
cos φ = efficiency (between 0.9 and 1)
y = Conductivity (copper 58, aluminium 37)
ua = voltage drop in %
U = Mains voltage in volts


Cable cross-sections for 230V applications with a cable length of 10 metres Power in watts Current in amperes
2.5 mm²  200 Watt  ~0.9A
2.5 mm²  500 Watt   ~2.2A
2.5 mm²  800 Watt   ~3.5A
2.5 mm²  1,100 watts   ~4.8A
2.5 mm²  1,400 watts  ~6.1A
2.5 mm²  1,700 watts   ~7.4A
2.5 mm²  2,000 watts   ~8.7A
2.5 mm² 3,500 watts  ~15.2A

Download table

Cable cross-sections for the following kW specifications

For 4 kW at 230V, a cable cross-section of 2.5 mm² should be selected.
For 7.5 kW at 400V three-phase current, a cable cross-section of 2.5 mm² should be selected.
For 9 kW at 400V three-phase current, a cable cross-section of 2.5 mm ² should be selected.
For 15 kW on 400V three-phase current, on the other hand, a cable cross-section of 4 mm ² should be selected.
For 18 kW 400V three-phase current, on the other hand, a cable cross-section of 6 mm ² should be selected.
For 30 kW 400V three-phase current, a cable cross-section of 10 mm² should be selected.


Excursus: Cable cross-section for wallboxes

Which cable cross-section for wallboxes?

The recommended cable cross-section for a wallbox depends on the maximum power in kW. For example, the supply cable for a wallbox should be 3-phase (400V) with 11 kW power and have a cable cross-section of at least 2.5 mm² ; 6 mm² is recommended. For a charging station 1-phase (230V) with 3.7 kW, the recommended cable cross-section is 6 mm².

Recommended cable cross-section of a charging station (wallbox) for an electric car at a glance:

Voltage (V) Current (A) Network max. power (kW) Conductor cross-section (mm²)
        Recommended at least
230 V 10A 1-phase 2.3 6 2.5
230 V 16A 1-phase 3.7 6 2.5
230 V 32A 1-phase 7.4 10 4
400 V 16A 3-phase 11 6 2.5
400 V 32A 3-phase 22 10 4

The operation of a charging station for an electrically powered car not only requires the recommended cable cross-section of the supply line: When connecting a wallbox, e.g. with 22 kW power, you must comply with the correct cable cross-section and obtain authorisation from your network operator.

If the cable cross-section in a motorhome is too small, a charging booster can help. It counteracts a voltage drop if a consumer with a power of 10 A is operated on a cable with a cross-section of only 2.5 mm².

Kabelquerschnitt-fuer-Wallbox-Ladesaeule

Cable cross-section for power cables, underground cables and house installations

A common question is: What cable cross-section should you choose for sockets? As a rule, a cable cross-section of 1.5 mm² is sufficient for individual sockets in a conventional house installation; if there are several sockets on a single-phase wire, the cross-section should be at least 2.5 mm².

What cable cross-section for house connection? The cross-section must be at least 16 mm².

Einzeladern-Ratgeberbox

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Single cores

H05V-K, H07V-K, H05Z-K, silicone, multinorm single cores and much more.

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What cable cross-section for underground cables?

The recommended cable cross-section for underground cables to supply house connections or building supply lines should be 16 or 25 mm². For individual consumers, e.g. in the garden, 1.5 mm² to 2.5 mm² is sufficient, depending on the application and power of the consumer.

Erdkabel-Ratgeberbox

Free cutting from 1 metre

Underground cable

Large selection in various core counts and cross-sections.

TO THE PRODUCTS

What cross-section for power cables?

For NYM cables, the respective cable cross-section is standardised according to DIN VDE 0295 and IEC 60228.

How much power (watts) or current (amperes) can a NYM power cable withstand? In this case too, the sizes of the cross-section depend on the maximum power of the consumer and the cable length. NYM cables with a cross-section of 1.5, 2.5 or 4 mm² are mainly used in the home.

Our NYM table provides information on the common NYM cables, whose cable cross-section has already been derived from the respective diameter.



Common NYM cables Protective conductor Number of cables x cross-section in mm²
NYM-J (earthing cable) with protective conductor 1x4mm² 
NYM-J  with protective conductor 3x1.5mm² 
NYM-J with protective earth 3x2.5mm² 
NYM-O  without protective earth 4x10mm²  
NYM-JZ  with protective conductor and tensile strength 7x1.5mm²  
NYM-OZ  without protective conductor and tensile strength 7x1.5mm² 

Download table


NYM-Kabel-Ratgeberbox

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NYM Cables

Large selection in various core counts and cross-sections.

TO THE PRODUCTS

Which fuse for which cable cross-section?

Once the wires have been laid, the question arises as to which fuse is required to protect the cable cross-section. The following tables show examples of frequently used fuses for the respective cable cross-section.

Current carrying capacity for alternating current
Cable cross-section in mm² up to 10m Fuse protection in amperes for cable laying in thermally insulated walls Fuse protection in amperes when laying cables in the installation pipe
Laying on cable trays or under the ceiling
1.5 mm²  16A  16A  20A
2.5 mm²  16A  20A  25A
4 mm²  25A  32A  35A
6 mm²  32A  40A  40A
10 mm²  40A  50A  63A
16 mm²  50A  63A  80A
25 mm²  80A  80A  100A
35 mm²  80A  100A  125A
50 mm²  100A  125A  160A
70 mm² 125A 160A 200A
95mm² 160A 200A 250A
120 mm² 200A 200A 300A

Download table


Current carrying capacity for three-phase current/power current
Cable cross-section in mm² up to 10m Fuse protection in amperes for cable laying in thermally insulated walls Fuse protection in amperes for cable laying in installation conduit Laying on cable trays or under the ceiling
1.5 mm² 10A 16A 16A
2.5 mm² 16A 20A 25A
4 mm² 20A 25A 32A
6 mm² 25A 35A 40A
10 mm² 40A 40A 50A
16 mm² 50A 63A 80A
25 mm² 63A 80A 100A
35mm² 80A 100A 125A
50 mm² 100A 125A 125A
70 mm² 125A 125A 160A
95 mm² 125A 160A 224A
120 mm² 160A 200A 250A


Further questions on the subject of cable cross-sections

Finally, we answer other frequently asked questions on the subject of cable cross-sections.

Which cable cross-section for which cable length?

In principle, the cable cross-section to be selected is also determined by the power loss, which depends on the respective cable length, among other things. The longer the wires, the greater the resistance, which means that a larger cable cross-section is required.

The following formula is again applied to calculate the cable cross-section for the respective length of the wires (for 230V alternating current):

A = 2 * L * I * cos φ / y * Ua.

Cable cross-section AWG/inch?

In addition to cables with metric sizes, cables are often also specified according to AWG - the American measure for wire sizes. The following applies to the cable cross-section according to AWG: The wire diameter decreases depending on how long a wire is drawn. The smaller the resulting cable cross-section, the larger the AWG value.

The respective cable cross-sections of an AWG cable can be found in the following table:

AWG no. AWG Designation ∅ in inches
Area in inches²
∅ in mm  Area in mm²
Resistance in Ω/km
Metric in mm²/km
-6  0000000 (7/0) 0,6513  0,3332  16,54  215,0  -   
-5   000000 (6/0) 0,5801  0,2644  14,74  170,6  0,10  185
-4   00000 (5/0) 0,5166  0,2096  13,12  135,3  0,13  150
-3   0000 (4/0) 0,4600  0,1662  11,68  107,2  0,17  120
-2   000 (3/0) 0,4096  0,1318  10,40  85,01  0,21  95
-1   00 (2/0) 0,3648  0,1045  9,266  67,43  0,26  70
0   (1/0) 0,3249  0,08291  8,252  53,49  0,33   
1   - 0,2893  0,06573  7,348  42,41  0,42  50
2   -  0,2576  0,05212  6,543  33,62  0,53  35
3   -  0,2294  0,04133  5,827  26,67  0,67   
4   -  0,2043  0,03278  5,189  21,15  0,84  25
5   -  0,1819  0,02599  4,620  16,77  1,06   
6   -  0,1620  0,02061  4,115  13,30  1,34  16
7   -  0,1443  0,01636  3,665  10,55  1,69   
8   -  0,1285  0,01297  3,264  8,367  2,13  10
9  -  0,1144  0,01028  2,906  6,632  2,68   
10   -  0,1019  0,008155  2,588  5,261  3,38   
11  - 0,09074  0,006467  2,305  4,172  4,27   
12   - 0,08081  0,005129  2,052  3,309  5,38  4 
13   -  0,07196  0,004067  1,828  2,624  6,78   
14   -  0,06408  0,003225  1,628  2,081  8,55  2,5 
15   -  0,05707  0,002558  1,45  1,65  10,79   
16   -  0,05082  0,002028  1,291  1,309  13,6  1,5 
17   - 0,04526  0,001609  1,15  1,038  17,15   
18   -  0,0403  0,001276  1,024  0,8229  21,63  1 
19   -  0,03589  0,01012  0,9116  0,6527  27,27  0,75 
20   -  0,03196  0,0008022  0,8118  0,5176  34,39  0,75 
21   -  0,02846  0,0006362  0,7229  0,4104  43,37  0,5 
22   -  0,02535  0,0005047  0,6439  0,3256  54,66  0,34 
23   -  0,02257  0,0004001  0,5733  0,2581  68,96   
24   -  0,0201  0,0003173 0,5105  0,2047  86,95  0,25 
25   -  0,0179  0,0002517  0,4547  0,1624  109,6   
26   -  0,01594  0,0001996  0,4049  0,1288  138,3  0,14 
27   -  0,0142  0,0001584  0,3607  0,1022  174,2   
28   -  0,01264  0,0001255  0,3211  0,08096  219,9  0,09 
29   -  0,01126  0,00009958  0,286  0,06425  277,1   
30   -  0,01003  0,00007901  0,2548  0,05098  349,2   
31   -  0,008928  0,0000626  0,2268  0,04039  440,7   
32   -  0,00795  0,00004964  0,2019  0,03203  555,8   
33   -  0,00708  0,00003937  0,1798  0,0254  700,8   
34   -  0,006305  0,00003122  0,1601  0,02014  883,7   
35   -  0,005615  0,00002476  0,1426  0,01598  1114   
36   -  0,005  0,00001964  0,127  0,01267  1405   
37   -  0,004453  0,00001557  0,1131  0,01005  1771   
38   -  0,003965  0,00001235  0,1007  0,007966  2234   
39   -  0,003531  9,792E-06  0,089697  0,006318  2817   
40   -  0,003145  7,768E-06  0,07988  0,005012  3551   
41   -  0,0028  6,158E-06  0,07112  0,003973  4480   
42   -  0,00249  0,00000487  0,06325  0,003142  5665   
43   -  0,00222  3,871E-06  0,05639  0,002497  7127   
44   -  0,00197  3,048E-06  0,05004  0,001967  9051   
45   -  0,00176  2,433E-06  0,0447  0,00157  11340   
46   -  0,00157  1,936E-06  0,03988  0,001249  14251   
47   -  0,001396  1,531E-06  0,03546  0,0009877  18021   
48   -  0,001243  1,214E-06  0,03158  0,0007832  22725   
49   -  0,001107  9,628E-07  0,02812  0,0006211  28657   
50   - 0,000986  7,635E-07  0,02504  0,0004926  36136   

Download table


Despite careful editing and checking of the content, Stecker Express assumes no liability for the topicality, correctness, completeness and quality of the information provided.


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