ᐅ Outdoor Electrical Installations – Have You Considered Everything?

Hello everyone,

This week we’re starting on the outdoor area, and before laying extensive paving, I want to coordinate with the landscaper to install the electrical wiring.

Current situation: From the utility room in the basement, there is a large empty conduit for electrical wiring for the outdoor area. Currently, the following run through it:

- 1x 5x10 cable for the wallbox charger -> will be located at the carport
- 1x 5x2.5 cable for a future sauna -> runs from the carport further into the garden
- 2x power cables for the carport (5x1.5)
- 1x network cable (RJ45) -> for the wallbox and anything else requiring network connection

Everything is connected to a separate residual current device (RCD) in the electrical cabinet. At the carport, all cables currently come out of the ground, properly sealed against moisture. Here I have my first question: How do you professionally bring these cables up from the ground once the area is paved? An outdoor floor box? What do I do with cables like the sauna line that continue further into the garden? I was simply planning to continue them in a separate empty conduit into the garden.

Since it was already quite difficult to pull these cables through the empty conduit to the outside, I would prefer not to add more cables there.

My idea is to install a small sub-distribution board in the carport (there will be a garden shed at the back) and run additional lines from there to supply the other devices.

This would include:

- Another 5x2.5 cable into the garden for a possible pool and anything else like a pump, etc.
- 3x1.5 cables towards the cistern (also in the garden)
- 3x1.5 cables in front of the house under the paving heading to the inspection chamber (for a backflow valve)
- 3x1.5 cables in front of the house towards the street for a potential future doorbell at the garden gate (not planned yet but who knows)
- 3x1.5 cables into the garden for garden lighting

Since the garden won’t be done at this stage, it’s important to lay the cables under the paving now so that they emerge near our soil mound.

Are there any other important points I should consider, or have I covered everything?

Best regards

I believe planning everything in advance is impossible. Equally impossible is predicting the technical developments of the coming years. For this reason, I would not skimp on empty conduit pipes. Feel free to lay 10cm (4 inch) KG pipes in the garden—that size can accommodate anything.

I would also install an additional empty conduit pipe in the basement. It’s still very easy to do now.

When I built, I proactively laid KG empty conduit pipes from the technical room beneath the house to another building, as well as further back into the garden.

All connections—electrical, heating, water, wastewater, etc.—then come out under the stairs inside the house. However, I can still pull cables into all the buildings.

At the time I planned, heat pumps, photovoltaics, and charging stations were not even considered. Without the appropriate conduit pipes, I would have had to dig up everything multiple times and with great effort. Just last year, I was able to run 40 meters (130 feet) of data and power cables through the conduit pipes from the meter cabinet to the technical room for the photovoltaic system without any excavation. This saved a tremendous amount of time and money.

The key with empty conduit pipes is choosing the right size. I never installed anything smaller than 50mm (2 inch) HT drain pipe; mostly 10cm (4 inch) KG pipes. And everywhere use sturdy, non-degrading pull ropes.

Thank you very much!

Is it really a complete no-go to lay a regular NYM cable inside an empty conduit (!) underground?

I always thought it was either NYY cable OR empty conduit. Whatever runs inside the conduit is protected anyway, right?

NYM refers to a conductor and NYY to a cable.
Conductors are used for indoor installations, while cables are suitable for underground use.
Using a protective conduit is either a luxury for installation or provides additional protection.

Possmann schrieb:

Another 5x2.5 cable to the garden for a possible pool and everything else that might come with it, like a pump, etc.

That might be a bit tight if you want to connect a heat pump later on. I would recommend 5x4 mm or even better, take 5x6 mm. 😉

LAN cable for access point, power supply for robotic lawn mower, power for cistern pump, control cables for pool, power for pool lighting, power for pool cover, socket for pool cleaner, control cables for irrigation, etc.
Overall, the cross-sections are generally too small depending on the load and cable length.