Electrical planning, what to consider? Procedure? Explanations and tips

Hello dear forum community,

time and again I am horrified to realize that many builders do not really give much thought to the electrical planning of their new home [Ausnahmen bestätigen natürlich die Regel]. Electricity is the hidden core of a house.

A brief introduction about me and my training: I am a trained industrial electrician specializing in operational technology with a master craftsman certificate as an electrical trade master. Although I am primarily active in industry, I can still handle a single-family house J

What do I want? With this thread, I want to try to support the uninformed a little. On the one hand, I want to explain some basic things, and on the other hand, to give valuable tips for planning. And when I have finished the text someday, I am very curious about possible discussions.

In advance: I belong to the fast typers who often overlook their own mistakes and have little desire to reread their own text. So please forgive various typos. I try to maintain a certain order in my explanations but have no concrete guideline, so it may well happen that I jump around in the text. Sorry in advance for this, but I just don’t have the desire for a proper guideline. Enough blah blah, let’s get started:

For Safety

The RCD
The RCD is a residual current device for personal protection, serving for your own safety.
By default, it should be installed as a 40A, 30mA version.
40A is the maximum current allowed to flow through the RCD and 30mA is the maximum fault current at which it must trip.
An RCD >30mA is not permitted.

One RCD for the entire house is not sufficient—don’t believe otherwise from your electrician.
A sensible distribution would be, for example:

1 RCD for the sockets
1 RCD for the lighting
1 RCD for building technology
1 RCD for refrigeration units
1 RCD for the outdoor area including garage/carport

Why all the effort?
If you only have one RCD and a fault occurs, your entire property will be in the dark. That’s very inconvenient.
By separating sockets and lighting, at least some light will still work somewhere.
The outdoor area should also always be protected by a separate RCD, since moisture can cause faults.
An RCD for building technology and refrigeration units is not strictly necessary,
but provides a significant advantage for example for your frozen food during summer holidays if the sockets in the living room fail, the same applies in winter for heating.
For permanently connected devices (i.e. not via a socket), an RCD does not have to be used.

The Fuses

The fuses protect the connected cables from being overloaded and eventually burning. As personal protection they are not sufficient (hence the RCD).

For private use, circuit breakers with B-characteristic are used. The B stands for the tripping behavior. In this case 5xIn.
Example 1:
A 16A breaker is installed, a short circuit occurs on the line and a total of 5x16A, i.e. 80A, flows, so the breaker trips immediately.

Example 2:
You have drilled into the cable but only nicked it, causing leakage currents between L and N. The current is still below 5x16A, so the fuse would not trip immediately in this case. However, it will heat up and trip after a certain time.
This time is defined by the “B” and can be read from diagrams. This time is also why a circuit breaker is not approved as personal protection.

Sizing of the fuses.

The fuses should at least match the cross-section of the cable behind them, but it is better to adapt them to the intended use.

For example, I use 16A breakers for sockets and 6A or 10A breakers for indoor lighting.
The reason for this differentiation is the aforementioned tripping time.

Max 10 sockets per 16A fuse. This is related to the diversity factor.
I was taught that on average 300W is consumed per socket. A 16A breaker can handle a load of 3000W, therefore 10 sockets.

Each room is protected by a separate fuse. A fuse costs somewhere around €1.00 in procurement, so don’t let them charge you excessively. Bear in mind though that each room will then receive its own line feed.

The same applies for lighting. Each room gets a fuse, so usually you don’t have to worry much about the number of fuses. One should be sufficient, unless you plan to install 1000W spotlights.

Large appliances such as washing machine, dryer, fridge, dishwasher, oven, hob, bean-to-cup coffee machines, etc. get their own fuse.
Especially devices with more than 2kW power. From 3kW upwards (instantaneous water heater), a 16A breaker is no longer sufficient, and the supply cable must be dimensioned larger as well.

You see, a lot adds up, so you should plan for a larger house connection box accordingly.
Also, an additional empty meter slot can be advantageous (for retrofitting a heat pump or photovoltaic system).

Basics of Electrical Planning

The standard designs in a construction service are never sufficient!
If you don't adapt them, you will regret it sooner or later.

Your electrical planning should be as generous as possible.
Subsequent changes are annoying, laborious, messy, and expensive.
Better spend a few euros less on the switch program (I know, glass frames look so great, no hardware store junk please) and invest rather in a few sockets, switches, lamp outlets, etc. etc.

Sockets:

You can never have enough!
I have a personal aversion to multiple sockets (sometimes it just can’t be avoided). They are not only a fire hazard, especially cheap goods, but also take up space behind the cupboard or are constantly lying in the way.

Personally, I say it’s not worth it to install just a single socket where one should go, always have at least two installed.
Time effort for the electrician, maybe 10 minutes more, material costs approximately 5€, electrician's hourly wage 40€(?), so about 6€ for installation. Thus, an additional socket from the standard program shouldn’t cost more than 15€.

Sockets should be planned at every window so you are prepared for decoration mania and possible window embellishments throughout the year.
Think about where your cupboards will be placed, also plan sockets for cupboard lighting there.
Under every switch group one socket (note, however, that the largest frame can contain a maximum of 5 elements).

Anywhere a TV is planned, at least 2, preferably 3 sockets should be installed. Reason: TVs are getting thinner, sound is getting worse, soundbars are increasingly used, so two sockets are already taken. The third is a reserve or for example for a media box (like Apple TV).
This socket group should be switchable on and off via a separate switch. (Electricity costs will continue to rise.)

Don’t be stingy with sockets when planning the kitchen either. Think about which devices you constantly have on the worktop (toaster, coffee machine, small electric grill, etc.). Those sockets are already planned. Additionally, 2 free sockets per worktop area.
Sockets on a kitchen island are also a blessing, or do you want to drag the cable for the mixer through the kitchen? (possibly with a multiple socket extension).

In the bedroom at the bed at least 2 sockets per side: 1x lamp, 1x charger for phone or whatever. Anyone who wants a TV in the bedroom should, as mentioned, plan the switch at the bed and at the door. From 4 switches onwards, a pulse relay must be added for the control. Before the electrician wants to install such an expensive pulse relay in the distribution (more cable effort = more work), point out that such a pulse relay can also be placed in the switch box.

In the bathroom, it must be ensured that sockets are not installed in wet zones.

The Media Center

Nowadays almost every household will have a media center somewhere, mostly in the living room. This includes, among others,
TV, AV receiver, game console, media box, Blu-ray player, subwoofer, charger for universal remote control.
That’s already 7 sockets, another three as a reserve can never hurt.
Remember 10 sockets = 1 fuse 16A.
Of course, all of these should be switchable on and off from a central point.
In addition to these sockets, there are speaker connection sockets for a 5.1 system (if you don't want to throw the cables across the room) and at least 2 network connections (the first 5 devices usually require one).
Speaker sockets, by the way, don’t have to be expensive from the switch program, just a frame and the base plate from the program are necessary, plus a few banana plug connectors from the electronics store (e.g. Conrad, Reichert, Pollin), and with some skill, you can save over 50% on the price.

Sockets outdoors on the house wall should be switchable from inside, and they must have a cover. Make sure the sockets are suitable for outdoor use (IP protection class).

Lamp outlets / light switches

Plan lamp outlets as you see fit.
Every non-connected lamp outlet should get its own switch.
For multiple switching points:
From 4 switching points, a pulse relay is required; this does not necessarily have to be installed in the connection cabinet, a cheaper version is a relay for the switch box.

In the hallway, the light should be switchable from every door; elegant solutions use motion detectors here (you come home with full hands).

Passing rooms should also be able to switch the light from every door (e.g., from the garage to the utility room).

To keep the switch panel from getting too large, serial switches can be used (2 switches in one frame).

I find lamp outlets at the bed quite nice, it saves me a socket.
Furthermore, the room lighting should also be switchable off from the bed.

Lighting in furniture. Carefully consider whether you really have to buy the offered lighting with the furniture purchase. This is usually completely overpriced.
Electronics stores (Conrad, Reichert, Pollin) offer the same lighting at much lower prices. With LED flex strips, very nice and cost-effective solutions can be created.

House lighting not only looks nice; it also scares off unwanted guests. Therefore, install a switch inside that lets you choose between permanent light or switching on via motion detector. So the light does not turn on everywhere when someone walks by, motion detectors can be installed on each house wall. However, this type of switching involves sometimes considerable additional effort.

Should you get roller shutters, plan a central timer for controlling the roller shutters. Additionally, you can install roller shutter switches at each window, but this is not necessarily required with a central timer (warning, if you only have the timer, you cannot operate the roller shutters individually). I always plan one timer per floor. Only have the window manufacturer deliver the manual roller shutters; you get the motor yourself via the internet. Rademacher is one of the top manufacturers, which also offers a second brand, sometimes with 10 years warranty and significantly cheaper. Pay attention to the wrench size of the roller in the box and the weight.

Network, Telephone and TV

Plan network sockets everywhere that TV, PC/MAC, laptop, router, etc. should have a place. A telephone is sufficient today in the utility room, hallway(s) and bedroom could also be useful. If you have planned enough network sockets, these can be easily used as a telephone socket. Please only use CAT7 cables, everything else is nearly outdated. CAT7 should not cost significantly more. You might save on the network sockets.

Example: Gira offers a network socket with cover in their range, and also a standard cover that fits a network socket from another manufacturer, in this case Telegärtner. Potential savings around 30%. Other manufacturers have similar options. Your electrician should know this.

I probably don’t have to say anything about TV, right?

The cables used (CAT7, antenna cable) must be laid in protective conduits underground as well as under the screed. In the attic or generally surface-mounted, cables may be laid and fastened with nail clamps.

So, I hope I haven’t forgotten too much about the electrical planning now and will close the topic for the time being. Next up is the electrical installation.

P.S. Power outlets in the workspace area (desk): PC, monitor, speakers, printer, scanner (5 pieces, switched).

Further note on the roller shutters: The roller shutter for the patio door should be able to be turned off via a switch so that it does not close at 10 PM by the timer while you are still sitting in the garden.

So, and with that I will first conclude my presentation. In conclusion, it should be said that my remarks are not final and certainly not complete. I have compiled this presentation to the best of my knowledge and belief. However, it has no validity except for the standards and laws from DIN VDE and the recognized rules of technology.