Electricity in the garden and garden shed – lay underground cables

Extreme caution is required whenever working with electricity. In principle, anyone can lay simple connections, but you can only be on the safe side if you let a specialist do it, in this case an electrician. In the case of high-voltage connections, this must be commissioned.

• All outdoor lines require a separate fuse, a separate fuse with a box!
• FI circuit breaker in the meter box is recommended (residual current circuit breaker)
• Only have heavy current or three-phase current plugs installed by a specialist (e.g. for sauna ovens)
• It is essential to use water-protected plug connections!
• To be on the safe side, the cables and all connections should not only be splash-proof, but water-proof and completely waterproof! These are usually underground cables.
• Only lay cables in the ground that are approved for this
• PVC Insulated Plastic Cable (NYY)
• PVC Insulated Plastic Cables with Copper Cores and Copper Conductors (NYCWY)
• Underground cable with aluminum conductor (NAYY)
• Put the underground cable in a special cable protection tube
• Alternatively, a cable cover made of clay or hard PVC can be used
• The cover is important so that you don’t accidentally damage the lines with a spade or other tool when gardening and risk an electric shock
• The underground cable must maintain a minimum distance of 30 cm to all other current-carrying lines, including telecommunications lines!
• Which cross-section you need for the cable depends on the strength of the fuse to which the cable is attached.
• If cables have to be connected to each other, special waterproof plug connections must be used.

Before you start laying the cable in the garden, you should make sure that no more electricity is flowing. Take out the fuses and measure whether the circuit is really dead.

Lay underground cable

Laying the cable is not difficult. It is important to keep the depth. For the garden that is 60 cm. 80 cm is the minimum depth under roadways. Don’t forget to cover the cables that protect against electrocution if touched while digging.

A sketch in which the position of the cables is drawn is certainly useful. In this way, they can be found again at any time, should this be necessary.

• The trench for the power cable must be dug at least 60 cm deep
• The bottom of the trench must be level and free of stones and other sharp objects
• Spread a 10 cm deep layer of sand throughout the trench
• Lay the underground cable on this bed of sand
• Unroll the cable slowly and carefully from the cable drum or roll, do not tug or pull!
• Either put the cable in a cable protection tube or cover it with cable hoods
• The cable protection tube has the advantage that not only does it provide protection, but you can easily replace the cable later without having to dig up the earth.
• Both provide space for an additional cable that may need to be laid later
• Add 10 cm of sand to protect against earth movement
• Lay a yellow PVC warning tape over the laid cable with the inscription underground cable (DIY store)
• The cable must be laid loosely and must not be under tension!

Several connections in the garden

If you need more than just one power source in the garden, you can work with several connections. Electricity can be diverted. For this you use socket sleeves, which are laid underground and bring electricity to all areas of a garden.

alternatives

As an alternative, lights can be operated using so-called low-voltage technology. The energy-saving and quite harmless LED lights are ideal. A generator is used for this purpose, which can be accommodated protected on or in the house. The low-voltage lines, which only carry a weak current, come from this transformer. These lines can be routed just below ground level in a spadeproof sewer pipe. This channel should be run along the edge of a bed or path.

If you want to avoid cables in general, you can use solar-powered lamps right away. However, they only work if they are placed in such a way that they get enough sun. The luminosity is usually significantly lower than that of lamps operated with electricity. However, solar lights are almost always sufficient for path lighting.

Cost of laying an underground cable

The cable itself is quite cheap. The prices depend on the thickness of the cable. The thinnest are available from around €1 per meter. The empty tube is cheaper. Here you can get 50 m for about 10 €. In addition, there are the costs for the electrician, with 100 € you have to reckon. Garden sockets start at around 40 euros, although there are also significantly more expensive models.

If you don’t want to go to the trouble of digging by hand, you can rent a small excavator, which, however, also incurs costs. Sand comes with it. It’s lapping. It makes more sense to get everything installed properly and spend a little more money than having to start all over again later.

Frequently asked questions?

Why do the cables have to be laid so deep?
If you know where they are, you can work carefully when gardening and save yourself a lot of effort. In theory this is possible. You remember the course and don’t plant anything there, except perhaps lawn. However, there is a problem when the house and garden are sold, the successor does not know this. Besides, there are regulations. Those who do not care much about this should consider that the ground freezes through more frequently and more severely in flatter ground. Frost damages the insulation over time. At first, water only penetrates through micro-cracks. When water freezes in them, they get bigger and bigger. At some point the whole insulation is gone and then it becomes dangerous.

Why can’t the lines be too long?
It is cheap to convert the more dangerous alternating current, i.e. the 220/240 volt, into direct current. That works with a rectifier. However, direct current does not work loss-free over long distances. The distance between the transformer and the end device should be kept as short as possible.