ᐅ Adding a second surface-mounted lighting circuit

Created on: 21 Apr 2026 12:06
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MarcomitZeh
Hello everyone,

In the kitchen of my single-family house, unfortunately only one light switch was installed, which controls a ceiling light. I would like to replace the single light switch with a double switch/two-gang switch to also be able to turn the retrofitted LED lights under the upper cabinets of my built-in kitchen on and off from the door, in addition to the ceiling light. Currently, these lights can only be controlled by motion sensors, so I have to wave my hand briefly under each of the four lights separately. The LED lights run on 12 V and each has a small plug-in transformer with a Europlug at the end of the cable, which are all currently plugged into a power strip above the kitchen counter.

Since this is only blurry in the photo: In the triple combination, at the very top is the light switch to be replaced, wired with a brown live wire and a switched grey live wire. Below it is a switch for the electric roller shutter of the kitchen window, and below that is a socket outlet. Everything is on a common circuit breaker. I had hoped to find an unused neutral conductor in this triple combination, so I could pick up the new switched live wire in the flush-mounted distribution box above the triple combination, but unfortunately all existing conductors are occupied, so I have to start directly at the bottom of the switch.

The plan now is as follows:

- Lay a two-core flat installation cable 2 x 1.5 mm (14 AWG) YDYp in a surface-mounted cable duct 12 x 7 mm, fixed to the wall with two-component epoxy adhesive (for permanent hold). Cable route see orange line. The cable has a solid copper core, not stranded.
- Carefully open the wall directly above the light switch to access the cable entry of the flush-mounted box, to avoid damaging already installed cables. The new installation cable will then be pulled into the topmost flush-mounted box as well. The cable duct will rest directly on the upper edge of the switch, and the cable will be completely hidden, routed through the back wall of the cable duct into the wall and into the flush-mounted box.
- Replace the single light switch with a two-gang switch, where the new switched live for the cabinet lights will be taken off. The neutral conductor will be connected where there is a free neutral terminal, e.g., at the socket outlet unit.
- Install a surface-mounted junction box above the cabinet.
- The plug will be cut off from a power strip and the cable firmly connected inside the junction box. To prevent anyone mistakenly assuming the power strip has a protective earth (PE) contact, a power strip with only Euro sockets will be used.

This is intended as a temporary interim solution until we have to renovate the kitchen completely in a few years anyway; at that time, the wall above the triple combination can be opened up and a new cable installed flush-mounted.

Technically this would work perfectly, I have no doubt about that. But is it also allowed?

Thanks for your well-founded opinions,
best regards
Marco



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MarcomitZeh
21 Apr 2026 19:09
user-d29 schrieb:
If it works, I don’t really care about its compliance.

The house is currently vacant but will be rented out soon. From a landlord’s perspective, compliance with regulations is a major issue, especially if you take liability and similar concerns seriously. Even as a private user, such matters shouldn’t be completely ignored; these standards exist for a good reason.
user-d29 schrieb:
Too bad none of the much simpler alternatives are interesting to you.

Well, what do you mean by interesting... I set a goal (to switch from the doorway) and the question is how to achieve exactly that goal — not any other. Installing a switch on the underside of the upper cabinet is a well-intended suggestion but it’s simply not what I want. Shelly would have been an option, but it doesn’t fit into the wall box. And honestly, it’s not that complicated to run an additional surface-mounted cable, so the other suggestions aren’t really that much “simpler.”

Is there no electrician here familiar with VDE standards who can answer my question?
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user-d29
21 Apr 2026 21:16
MarcomitZeh schrieb:
Is there no electrician here who is familiar with VDE standards and can answer my question?

No, this forum is for homeowners. You should ask in a specialized electrical forum.

Besides, the effort for renting out is too much for me. You MUST hire a licensed electrician for this, as it is prohibited for private individuals to do such work themselves according to the standards. Since you want to comply with regulations, and especially when renting out, it is dangerous to tamper with electrical installations on your own. You would be personally liable because you are not an electrician. It’s really a major issue.

I am a landlord myself and would never do something like this myself. It can really cause serious problems.
Knöpfchen21 Apr 2026 21:39
Is an installation as I have planned permissible?

No, the protective earth conductor must always be connected.
According to the new VDE 410 standard
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MachsSelbst
21 Apr 2026 22:42
By the way, it is ALWAYS an issue if you tamper with the electrical system yourself when you are not allowed to.
If the house burns down and the insurance proves that the fire was caused by improper electrical work, you will not receive a single cent.

This is even more serious in the case of renting out the property, because then you would also have to cover the tenant’s damages and might end up in court for negligent bodily injury up to negligent manslaughter.

In general, with electrical work:
If you need to ask for advice in an online forum, you should stay away from it because you lack the necessary knowledge. Too much can go wrong if you make a mistake, as laypersons usually do not have the proper measuring instruments to check their work after completion. Insulation resistance, loop impedance, trip time and trip current of RCDs, and so on—all these parameters must be measured for the relevant circuits once the electrical system has been modified...
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MarcomitZeh
22 Apr 2026 14:04
user-d29 schrieb:
You MUST hire a licensed electrician for this, as it is prohibited by regulations for private individuals to do such work themselves.
MachsSelbst schrieb:
By the way, it is ALWAYS an issue if you tamper with electrical installations yourself without authorization.
If the house burns down and the insurance proves the fire was caused by improper electrical work, you won’t receive a single cent.

What do you think—I have done a lot of electrical work myself, even in rental properties. This is generally allowed as long as a certified electrician inspects and approves the work before it is put into operation.
MachsSelbst schrieb:
If you have to ask about this on an internet forum, you should stay away from it because you clearly don’t know what you’re doing.

Whenever I read this kind of comment, I have to roll my eyes. By that logic, the entire Electrical/Electrical Planning section of the forum would be pointless—if you need to ask, you should just give up and not participate in the forum. And anyone who already knows everything wouldn’t need a forum at all because they already know everything.
Knöpfchen schrieb:
No, the protective earth conductor must always be connected.
According to the new VDE 410

Thanks, Knöpfchen, for the first and so far only answer that actually addresses the question. Of course, I could also take the PE (protective earth) from the socket, then run the switched phase, neutral, and PE in the cable duct upwards, install a surface-mounted socket with Schuko top of the cabinet instead of the surface-mounted junction box, and then the Euro power strip could be omitted. Would that be okay?
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user-d29
22 Apr 2026 14:12
MarcomitZeh schrieb:
This is generally allowed, as long as an electrician inspects and approves the in-house electrical work before it is put into operation.

Then alternatively, just ask your electrician, the one who usually approves your electrical installations anyway. You need them regardless.