ᐅ Extending/Connecting Outdoor Electrical Wiring

Hello everyone,

Slowly but surely, we are starting to plan the irrigation and electrical setup, as well as the planting of our outdoor area.

I am especially uncertain about the electrical part and would like to know how to approach installing electrical wiring outdoors.

I have had my landscaper install two underground cables (3-core) in two different locations. These are connected to a permanent power supply.

The cables are currently lying in my yet-to-be-planted flower bed, waiting to be extended.

The plan is to route the cable from the current eastern area to the southern area (a 19-meter (62-foot) long hedge). We want to install a few spotlights there.

Therefore, the cable needs to be extended and split along this 19-meter (62-foot) length to connect several spotlights.

Since I have only basic knowledge of electrical work (connecting lamps) and have no idea how to handle outdoor electrical wiring properly, I’m reaching out to you here.

I’ve read about systems (not mentioning brand names here) that come with their own cables and spotlights, but those are too expensive for me...

How do I properly lay, extend, and split the electrical cable outdoors and connect it correctly and waterproof?

There are waterproof cable connectors and splitters available. You can also find them using these search terms. It does not have to be a proprietary system. If necessary, install a distribution box. However, some experience with electrical work is advisable.

A three-core cable with constant power is initially not suitable for controlling spotlights and possibly different circuits from the inside. How are the spotlights supposed to be switched at all? Extending the cable is actually the lesser problem.

houser schrieb:

A three-wire cable with continuous power is initially not suitable for controlling spotlights and possibly different circuits from the inside. How are the spotlights supposed to be switched at all? Extending the cable is actually the lesser problem.

Ultimately, I was thinking of controlling the spotlights using a timer switch. Doesn’t something like that exist?

Honestly, I hadn’t given it much thought beforehand and assumed that once my landscaper runs the cable to different locations, I could decide what to do from there.

Do I need to install a distribution box first to even have an option?

I thought there would be appropriate lighting solutions where the spotlights can be controlled separately or potentially also by a timer switch.

Prager91 schrieb:

Ultimately, I was thinking about controlling the spotlights with a timer switch. Isn't there something like that?

There are socket columns with integrated timer switches. But since sunrise and sunset times constantly change, you might have to adjust the times frequently. Alternatively, you could use some kind of radio-controlled smart home solution. However, I would have had five wires installed, with at least one wire switched from inside.

Prager91 schrieb:

Actually, I didn’t give it much thought beforehand and figured that once my landscaper runs the cable to different spots, I can decide what to do from there.

Do I need to install a distribution box first just to have the option?

I thought there would be suitable lighting options available so that the spotlights can be controlled separately or maybe even by timer.

Everything needs to be installed in a waterproof manner somehow. Having a separate residual current device (RCD) for outdoor circuits would also be beneficial, because if something trips the RCD, it won’t affect the house immediately. Often, such faults in outdoor wiring (for example, if water has penetrated somewhere) are only noticed days later, and during that time you may not be able to reset the circuit.

houser schrieb:

There are socket columns with integrated timers. But since sunrise and sunset times constantly change, you’d probably have to keep adjusting the settings. Alternatively, you could use some kind of radio-controlled smart home solution. However, I would have had a five-core cable installed, with at least one conductor switched from inside.

Everything must be done watertight somehow. Having a dedicated RCD (residual current device) protection for outdoors is also beneficial. If something trips the RCD, it won’t affect the entire house. Often, faults in outdoor wiring (for example, when water has entered somewhere) only show up days later, meaning you can’t reactivate the circuit for some time.

In fact, I had a five-core underground cable, or rather, I still have one wired with constant power and an internal on/off switch. I had this cable extended, but only with a three-core cable because my landscaper is not an electrician and said he could only extend or lay a three-core cable. Now I have a three-core cable hanging outside.

That’s exactly the issue I had with the RCD.

The cable was lying in water last summer and tripped the RCD, cutting power to the living area. It took me a while to realize it was the outdoor cable causing the problem...

So it definitely makes sense to connect the cable to a small distribution box with an RCD, right? From there, I could run to a socket column or even connect something via smart home control.