How to run 240 electrical cables

Lay power lines

Lay cables under plaster - get rid of the tangled cables

Tangled cables under the desk, in the living room or in the kitchen are not only very messy, but also dangerous. Loose wires and cables are potential tripping hazards and overloaded connector strips can lead to a fire. So if you want to eliminate sources of danger and tangled cables, cables should disappear in the wall or at least attach them to the wall.

The use of empty conduits is recommended for new construction or renovation of a house. The advantage of these pipes is that they also offer the option of installing additional power lines at a later date. These are solid PVC pipes with a diameter of 13.5 mm to 16 mm.

Fixed PVC pipes with appropriate fastening clamps, into which the pipe is simply pressed, are ideal for exposed laying (on plaster). Of course, you can also use a cable with the conventional cable clamps that are attached to the wall with steel nails. Special skirting boards with cable slots are also available. However, it is more elegant to hide pipes or cables under the plaster.

The right lines

Cables or wires are optionally offered as pipe, cable or flat cables (flat cables). Basically, it is important to use the correct installation cables when laying.

Flat cables (NYIF-J flat cables)

Ribbon cables are flat cables and are available by the meter. The live cables are already installed in the ribbon cables. They are available as three- or five-core cables with a conductor cross-section of 1.5 mm² each.

Flat cables may only be laid flush-mounted in dry rooms without additional protection. In basements they are only allowed for interior walls. Flat cables are around 3.8 mm thick and can be laid very easily under the wall. Because you only need very little space, it does not have to be cut into the hard masonry. The flat cables are then attached to the masonry with special nails.

Installation cable (NYM-J cable)

Installation cables are PVC-sheathed copper lines (3 to 5-core) that can be laid on or under the surface. Such narrow installation cables have the advantage that they only need a narrow mortise slot for laying under the plaster. That saves a lot of chiselling work.

Depending on the load on the ladder, you need a certain cross-section. The higher the load, the larger the cable cross-section must be selected. For the normal house network, conductors with a cross-section between 1.5 mm² and 2.5 mm² are sufficient. For large consumers such as electric stoves, the cross-section must be 4 mm².

Find an electrician
Cheap offers

  • Nationwide network
  • Qualified providers
Tip: Find the cheapest electricians, compare offers and save.

Types of cables and their uses

  • 1.5 mm² for lighting and sockets with less load
  • 2.5 mm² for heavily loaded sockets (tumble dryers, dishwashers, boilers, etc.)
  • 4 mm² for electric stoves and more powerful machines in the hobby workshop or garage
Tip: In the case of concealed lines, it is recommended that these are plastered only after a function test!

Laying power cables can be done by any DIY enthusiast. However, the electrical connections should be made by a specialist. It is also advisable to consult with an electrician before laying cables, who will specify exactly where and which cables must be laid.

Cables that are laid flush, as well as for switches and sockets, apply certain installation zones. Lines laid horizontally must run 30 cm or 15 cm above the finished floor or 30 cm below the finished ceiling surface. Vertically laid cables should run 15 cm next to the edges or corners of the shell.

Separate regulations also apply in kitchens and housework rooms. Separate stipulations also apply in the bathroom.

Lay cables under plaster step by step

If pipes, lines or cables are laid in wall slots, these slots may not be too deep, depending on the wall thickness. In principle, no wall slots for electrical lines may be chiseled on chimneys. And: Wall slots must not impair the stability of the wall!

Wall thickness greater than 115mm

  • Maximum slot depth 10 mm
  • Slot width maximum 100 mm
  • Distance between the slots at least 115 mm

Wall thickness greater than 175 mm

  • Maximum slot depth 10 mm
  • Slot width maximum 100 mm
  • Distance between the slots at least 115 mm

Wall thickness greater than 240 mm

  • Maximum slot depth 30 mm
  • Slot width maximum 150 mm
  • Distance between the slots at least 115 mm

Wall thickness greater than 300 mm

  • Maximum slot depth 30 mm
  • Slot width maximum 200 mm
  • Distance between the slots at least 115 mm

Wall thickness greater than 365 mm

  • Maximum slot depth 30 mm
  • Slot width maximum 200 mm
  • Distance between the slots at least 115 mm

When laying pipes, lines or cables you should proceed as follows:

  1. Mark the route of the lines and carefully check the wall for power and water lines with a line finder.
  2. The holes for the flush-mounted boxes are drilled with a drill bit and a drill. Be it for switches, sockets or junction boxes. Knock out the drill core with a small chisel and hammer without damaging the surrounding wall.

    There are three standards for laying electrical cables:
    1. Working with hammer and chisel or
    2. You mill two slots in the wall with an angle grinder and a suitable stone or diamond disc and remove the middle bar with a hammer and chisel.
    3. I recommend one Wall chaser. Such a device can be borrowed from 40 euros per day. The wall chaser is equipped with a suction device for an industrial vacuum cleaner, so that a largely dust-free work is guaranteed.

  3. The wall chaser is set to the routing depth on the setting lever. The two milling disks run without a cover. Connect an industrial vacuum cleaner to the device, because the milling dust is very fine and settles in even the smallest of joints and pores. The wall chaser must be set on carefully. There is a risk of kickback, especially with hard concrete walls.
  4. The thickness of the wall determines the maximum slot depth (see table above).
  5. The middle bar between the slots is now worked out with a hammer and a hammer.
  6. The box is then plastered into the wall with plaster of paris or electrician's plaster. After drying, the pipes or cables are pulled in. Special fastening clips are available for fastening. There are special flat line nails with plastic insulation on the head for flat cables. Finally, the slots, including the cable and its fastenings, are sealed with plaster of paris or filler.
  7. IMPORTANT: Disconnect power and data cables!

    When laying power lines, you should make sure that lines are not directly next to data lines. The voltage can interfere with data transmission to the computer or telephone. Alternatives: use two different conduits, use separators or use shielded data cables. Otherwise, the minimum distance between the electrical cable and the unshielded data cable should be between 100 and 200 millimeters.

    IMPORTANT: It is not without reason that the installation of electrical systems is one of the master craftsmen in Germany. This means that the electrical installation must be carried out by a master company and is taboo for laypeople! This prohibition applies to all electrical systems in the house.

    Find an electrician
    compare offers

    Tip: Register for the newsletter now

    Receive the most important news monthly and free of charge directly in your mailbox
Tags:Electrical installation