Last updated: August 12, 2021
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Welcome to our big earth cable test 2022. Here we present all the earth cables we have tested in detail. We have compiled detailed background information and added a summary of customer reviews on the Internet.

We would like to make your purchase decision easier and help you find the best earth cable for you.

You will also find answers to frequently asked questions in our guide. If available, we also offer interesting test videos. Furthermore, you will also find some important information on this page that you should definitely pay attention to if you want to buy an earth cable.




Summary

  • earth cables are needed when cables have to be laid underground. The cable is protected from external influences by insulation made of PVC, PE, rubber or PUR.
  • You can choose between low-voltage cables, medium-voltage cables and high-voltage cables when buying an earth cable.
  • The cross-section, the cable length, the conductor material and the number of cores should be taken into account when buying an earth cable.

The Best Earth Cable: Our Picks

Guide: Questions you should ask yourself before buying an earth cable

What material is an earth cable made of?

Copper is the most commonly used conductor material, followed by aluminium. The most common insulating material today is PVC, followed by PE, rubber and PUR. PVC or polyethylene is used for the sheathing.

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Earth cables are particularly well insulated cables that can be laid underground. They can be bought in DIY stores, for example. The selection is also growing online. (Photo: Tomasz_Mikolajczyk / pixabay.com)

Copper is the most commonly used conductive material because of its high electrical conductivity. However, since aluminium is 2/3 lighter, it is cheaper to buy and therefore a real substitute for copper.

Insulation that can be used for earth cables usually has to be plastic or elastic. PVC (polyvinyl chloride), PE (polyethylene), rubber or PUR (polyurethane) are ideal. The energy loss of PVC increases with increasing frequency and length, which is why broadband signal cables, high-frequency cables and also telephone lines are often insulated with PE.

The cable sheath protects the cable from external influences and may contain a shield. Today, plastics such as polyurethane or polyethylene are used in addition to PVC. Polyethylene is very inexpensive, but flammable. PVC produces toxic gases such as hydrogen chloride and dioxins when exposed to fire.

For this reason, halogen-free, flame-retardant cables and conduits are used in modern buildings with large gatherings of people, such as railway stations, airports, museums, congress halls and department stores. For flexible, heavy-duty cables, rubber is used as a sheath.

How much do earth cables cost?

The cost of an earth cable depends on the length and the size of the cross-section of the cable. The costs for laying the cable are extra.

In online shops, earth cables with a length of 1 metre and a cross-section of 2.5 mm can be purchased for 0.65 euros. The price also depends on the number of wires that come out of the cable. For example, an earth cable with five cores costs about 1.35 euros per metre.

In addition, depending on the nature of the soil, the ground covering, the supplier, the depth of the trench and the required safety measures, about 80 additional euros per metre will be charged for laying the cable.

Who lays earth cable?

In principle, you can lay the earthcable yourself. However, we advise you to have it done by an expert, as it requires the necessary tools and some regulations have to be observed.

On the internet you can find numerous instructions on how to lay an earth cable to provide power for garden lighting, water pumps for a pond or electricity for a garden shed. For a hobbyist, however, this can be a difficult and tedious undertaking.

For example, a hole at least 60 cm deep must be dug - a real feat without an excavator. In addition, numerous safety precautions must be taken to avoid electric shocks and the collapse of the soil.

So if you're the lazy type with no electrical experience, we recommend that you hire a company to do the work for you.

What cross-section does your underground cable need?

The necessary cross-section depends, among other things, on how many metres of cable you have laid and what you want to connect to the respective line.

Basically, you can calculate the necessary cross-section yourself. The general formula for this is:

A = (I * p * L * 2) / Uv

  • A = cross-section
  • I = current in amperes.
  • The current consumption results from the power P divided by the voltage U, calculating with cos φ = 1. This means: I = P : (U * cos φ) = P : U * 1 = P : U
  • p = specific resistance of copper
  • L = required length of the earth cable
  • Uv = permissible voltage loss

Decision: What types of underground cables are there and which is the right one for you?

Which earth cable do you need and what are the advantages and disadvantages?

There are different types of earth cables, which differ in their construction and area of application. Basically, a distinction is made between low-voltage cables, medium-voltage cables and high-voltage cables.

Electrical lines in the area of low-voltage networks at voltages between 0.6 and 1 kV and medium-voltage networks at voltages below 70 kV are usually constructed as earth cables in Europe and in the area of residential or industrial areas.

High-voltage cables with operating voltages of over 200 kV are used when large amounts of electricity have to be transported over long distances from point to point. From a distance of 10 km, high-voltage cables are used.

So if you don't have too much power consumption, a low-voltage cable is perfectly sufficient to supply your house with electricity. For consumers with a somewhat higher energy consumption, medium-voltage cables are a good choice.

Here we list the advantages and disadvantages of earth cables compared to overhead lines:

Advantages
  • Protected against damage - including weathering
  • Does not spoil the landscape
  • More durable
Disadvantages
  • More expensive
  • More frequent maintenance
  • Higher transmission losses
  • More difficult to locate damage

Buying criteria: Use these factors to compare and evaluate earth cables

In the following, we would like to show you which criteria you can use to compare and evaluate LED lamps. This will make it easier for you to decide whether a certain device is something for you or not.

In summary, these are:

  • Cross-section
  • Cable length
  • Suitability for outdoor use
  • Conductor material
  • Number of cores

Cross-section

As already described in the guide text, the cross-section of an earth cable depends on the depth at which the earth cable has to be laid and on the number and type of devices that are to be connected.

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Basically, each cable is equipped with a blue, a brown and a yellow-green cable. Some cables also have a black and a grey cable.

Basically, your earth cable can never be too thick, only too thin. A cable that is too thin will get too hot if it is overloaded and will no longer be able to conduct the current efficiently. A thicker cable does not have this problem, but it is much more expensive.

Therefore, we advise you to use the above formula to calculate the cross-section. If you find this difficult, consult an expert.

Cable length

The length of the cable depends on how large the area to be supplied with electricity is. But be careful: the longer the cable, the greater the so-called voltage drop.

Due to the ohmic, inductive and capacitive resistance of the conductor, a voltage drop occurs, which can lead to various electronic devices no longer functioning properly with long cable lengths or no longer providing full power, as the full voltage no longer arrives.

The voltage drop can be compensated to some extent by a larger cross-section. Here we list some example calculations (3-core cables with low voltage):

  • 3 x 1.5 mm² not longer than 19 metres
  • 3 x 2.5 mm² not longer than 30 metres
  • 3 x 4 mm² not longer than 49 metres
  • 3 x 6 mm² not longer than 72 metres

Suitability for outdoor use

You can find out whether your earth cable is suitable for outdoor use in the product description. The cables are usually laid in a tube under the ground. The outdoor installation must be protected by its own automatic circuit breaker.

The earth cables for outdoor use therefore need their own fuse in the fuse box. In addition, you should install a so-called FI circuit breaker in the fuse box, as it switches off immediately in case of irregularities.

Especially in the garden, where water can always be involved, an electric shock could be life-threatening. If you cannot retrofit the RCD switch, you should at least use intermediate RCD plugs.

Conductor material

Today, almost all earth cables are made of copper. Copper is an excellent conductor because of its high electrical conductivity. Copper has a lower electrical resistance than aluminium. However, aluminium is cheaper to buy.

Number of cores

The number of cores depends on the intended use. Three cores are the minimum number. Basically, each cable has one blue, one brown and one yellow-green wire. Some cables also have a black and a grey cable.

The three-core cables are used if you only have sockets. As soon as you have a switch with you that switches a lamp, for example.

Facts worth knowing about earth cables

How deep must earth cables be?

earth cables must be buried at least 60 cm deep, and even 80 cm deep under roadways.

What colour is an earth cable?

Low-voltage earth cables have a black outer sheath, medium-voltage power cables or earth cables with a PVC sheath have a red outer sheath and those with a PE outer sheath have a black outer sheath.

What do the abbreviations of the cable types mean?

If you have already studied earth cables a little, you will have noticed that the cables are named NYM-J 3×1.5, for example.

Here we will explain step by step what the abbreviations mean:

  • N = Standard cable
  • Y = Insulation of the cores made of PVC
  • M = sheathed cable
  • -J = with green-yellow protective conductor (-O = sheath without green-yellow protective conductor)
  • 3 = number of cores
  • x = "times
  • 1.5 Conductor cross-section in mm

Image source: ulleo / pixabay.com

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