Electricity in the garden – lay underground cables yourself – instructions

As part of a new building, a trench must be dug for the house connections at some point. An underground cable goes in here, but much more:

In this case, a few things must be considered before digging. Into this ditch goes all the utility lines, water and gas lines, a telephone line, cable connection, etc. So here you have to plan ahead and coordinate the work of several people involved. You’ll have to be a bit persistent at times when planning ahead. Less so in the case of the municipality or the companies commissioned by it, for them it is daily bread and normal that all supply lines are laid in one route and that this happens at the same time. Instead, telecommunications companies like to cause surprises here, sometimes flat-rate costs for house connections are quoted, where it is initially ignored for a long time that there is an open ditch, i.e. no civil engineering costs are incurred.

You can also place an underground cable for the garden power in the general house connection ditch. If you don’t yet know whether and where garden electricity should go, at least an empty pipe for it (and preferably other empty pipes for all sorts of things).

You are not allowed to lay the underground cable for your house completely yourself, the local network operator is involved here. You may, however, make your own contributions; Your network operator will explain exactly what they should look like, usually in information packages that can be downloaded from the Internet with all the necessary forms. There’s a lot to consider aside from simply swinging a shovel

Own work at a glance

• apply for the planned contribution in good time
• fill out certain forms, including additional ones. the normal house connection
  • For example, a document called “House connection documentation for empty pipe laying by customer service” or similar.
• Then carry out the documentation carefully
• It is the basis that allows house connection cables to be repaired in the event of damage without damage to the ground.
• Documentation is for your personal protection if you later carry out earthworks near the route.

Further specifications for underground cables:

• As a rule, construct a supply trench at right angles to the building
• If the connection line runs parallel to the building, a minimum distance of 1 meter must normally be maintained.
• Clear the floor of stones
• Trench must have a certain width depending on the depth and be filled with sand up to a certain height.
• You have to bring/place the sand.
• When the utility lines are then laid, you must ensure that the trench is filled in immediately afterwards.
• You have to lay a route warning tape approx. 0.3 m below the future surface of the earth.
• Overall, all connection lines should be routed to the house via the shortest (right-angled) route.
• Any pre-lays that connect the supply lines located in the public area with the respective connections must be taken into account.
• Overbuilding is not permitted over the route, not even later.
• Access to the connecting lines must be possible throughout, so larger plants/trees may not be planted on the route.
• The house connection work is only tackled by the grid operator at a certain stage of your house construction.
• Usually when the excavation pit has been backfilled to the final height.
• Free access to the route without scaffolding and building materials etc. must also already be guaranteed.
• All boundary points of your property should be clearly visible.
• A house connection box is part of the connection, in the house connection room, on the house connection wall or in the house connection niche.
• When planning this excavation and laying work, a large number of standards must be observed, which are listed in the client information on own work.

savings potential

If you undertake the construction of the supply ditch on your property, you save on the house connection. Here is a price example from a typical German network operator:

1. The network operator does everything

Basic amount €1,016
+ 20 m cable duct on property €560 + meter installation €
60
makes €1,636 net
+ 19% VAT €310.84
total €1,946.84

2. They dig

Basic amount €1,016
+ the same amount for cable duct on property €560
– Remuneration for own work for digging €260
– Remuneration for own work for breaking through wall €44
+ meter installation €60
makes €1,332 net
+ 19% VAT 253 €
.08 total €1,585.08

The basic amount remains with you. But there is also a lot to be done with the underground cable: digging a sleeve and assembly pit and the cable trench in the public area, laying the cable in the public area, the cable entry into the house (in the first room on the outside wall) and the assembly and provision of the house connection box.

But what you also get is €300 for 20 m, which is the largest part of the cost of digging on your property. Which would be justified if the grid operator inspects and approves the trench you dug and assumes liability for the cable he has now laid; You should always check carefully how liability is regulated in the case of personal contribution.

After all, as a private individual who is not entitled to deduct input tax, you save €361.76 in our example. Whether digging 20 meters is worth it to you could perhaps be considered against the background of saved fees for a fitness studio.

How much electricity do you need in the garden?

If the house connection has been in use for a long time and you want to install electricity in your garden later, you should first think about how much electricity you really need to have ready in the garden. If you really only want light in the garden and need electricity for an electric hedge trimmer at most once a year, you could bring in the light from solar (and at the party with additional lighting with burn-proof oil lamps) and operate the electric hedge trimmer with a cable reel.

Where solar lights would not be so cheap because they found “lovers” too quickly, you could install permanent lighting with low-voltage cables that are operated with LEDs. At the beginning of these cables is a transformer, which can be housed in (or protected on) the house, from which the low-voltage lines, which only carry weak current, go. While such underground cables cannot simply be thrown into the garden either, you can run these cables in a spade-proof sewer pipe or duct just underground. You should only make sure that the cable is not damaged every time you dig a spade, the “small route” should rather be led along the edge of a bed or path.

“Real electricity” in the garden

If you later want to lay an underground cable in the garden, you only need to pull this underground cable into your free cable duct if you have inserted empty conduits for the house connection as suggested above. Even if you have bought a finished house, you should always check whether the previous owner was far-sighted enough to insert conduits. Then all you have to do is ask the electrician who connects the outdoor cable to the fuse etc. to bring a pull-through spiral and pull-wire – and save yourself a lot of sore muscles.

If you can’t find any tubes that can be fitted, but you need more than low-voltage cables, you’ll have to dig:

Lay the underground cable later

If you want to lay an underground cable to supply the garden with electricity in such a way that you can connect any light you want and maybe even a drill etc., you need an underground cable that supplies enough power.

That must first be calculated by an electrician depending on what you want to connect. The electrician will also be needed to branch off your house connection box and make the necessary installations at the other end of the lines. There are a few things to note here: Only an electrician licensed by the electricity supplier may work on the house connection box, and the lines for the garden must be specially secured. You need a residual current circuit breaker (formerly FI switch, today RCD).

There are also other regulations to be observed for such underground cables, here is an overview:

• Lay at a certain depth depending on the property and cable route
  • Normally 60 cm deep, in certain cases (roadway etc.) 80 cm.
• Maintain a certain minimum distance from other power lines (telephone lines).
• Clear the ditch for the cable from stones and equip it with a sand bed
• You need the right cable protection tube and/or cable protection hoods
• design all connections with couplings approved for outdoor use
• Sand and the route warning tape come over the cable again before it is dug up.
• You can dig yourself, and after an electrician’s assessment, you can also insert cables
• You need a properly sized, outdoor-approved underground cable.
• All components must be protected against moisture and splashing water
• unless you install piece by piece and close the trench immediately, you may need to brace the side walls of the manhole
• Sockets in the garden must have a cover, or you can provide a so-called energy column.
• weatherproof power source can be camouflaged with decorative elements
• If in doubt, lay out the lines strong enough to connect other power sources such as e.g. B. to be able to supply a pond pump.
• if the energy column is in an area that is easily accessible to the public, it should be equipped with a lockable cover