ᐅ What does modern electrical wiring in a house involve? A practical example...
Created on: 2 Feb 2019 15:05
M
MycraftHomeowners often ask themselves:
- Do I need this or not?
- Are the additional costs justified?
- What are the advantages?
- What are the limitations?
- What exactly is a smart home?
For this reason, I would like to share some of my experiences.
I have been living in an automated house with modern electrical systems for about 7 years now. Whether it is smart, automatic, or intelligent – I’ll let the reader decide. I will provide examples of how we implemented certain features to give an idea of what is possible. I would say our house is rather moderately automated, as I know of examples where much more has been done.
Smart homes / Modern electrical systems / Intelligent houses – all these terms somehow describe similar things, but everyone imagines something different. Especially if you have no background and have only ever known the usual: clap your hands or flip the switch → light on!
Every manufacturer who offers switchable outlets, motion detectors, and perhaps thermostats with a central controller calls it a smart home.
But that is not actually smart at all. At most, it just makes daily life a bit easier.
Because outlets with timers, lights with motion detectors, and a heating system that maintains or automatically adjusts the temperature are simply three different systems that can coexist side by side with central control and perform their tasks. Such helpers existed 30 years ago as well, but back then nobody called that a smart home.
Even adding a voice assistant doesn’t automatically make it a smart home.
If you want, you could call it an automatic house.
Smart homes, meaning “intelligent” houses, are much more than that.
It becomes “intelligent” when many systems and devices from different manufacturers are integrated so that processes interact and synergies emerge.
Functions can and must be customized to the specific needs and habits of the homeowners, taking the environment and external influences into account. Of course, all this should be economical, flexible, and easily expandable or modifiable at any time.
Seven years ago, we also faced the decision of which system to choose and considered many options.
What was important to us:
- No closed solutions, meaning no dependence on one manufacturer or cloud service
- Availability and variety of components
- Flexibility and scalability
- No batteries or additional adapters
- High reliability
- Future-proof design
- The ability to let multiple systems work together, not just alongside or against each other
- Costs
Discreet installation was especially important to us. We wanted the technology but as invisible as possible. It’s understandable that displays, switches, and presence detectors are more noticeable than regular light switches, but the rest of the system is hidden. There are no additional sensors glued or screwed onto windows or doors – only the end devices at the outlets.
Everything was implemented with KNX technology by a skilled professional and myself.
Currently, the house includes:
- About 100 outlets, around 30% of which can be switched individually
- 48 switchable channels in total
- 15 lighting groups, 8 of which are dimmable
- 14 roller shutters
- 2 built-in touchscreens plus other portable control devices (laptop, iPhone)
- Various temperature, gas, CO2, air quality, and light sensors
- 8 presence detectors
- 8 switches with displays, each with 3 rocker switches (6 buttons)
- 10 smoke detectors
- 30 LAN ports
- 8 IP cameras
- 8 satellite connections (for 3 TVs)
- 1 voice control system
- 1 weather station
Examples of our automation:
Shading, climate, ventilation, and heating control
To prevent overheating in summer while maximizing solar energy gain, these systems need to work together.
The heating system detects through indoor temperature sensors that heating is not currently necessary and circulates water in the floor to slightly maintain temperature because the weather station reports a warm day. Indoor and outdoor temperature sensors observe the difference and adjust the ventilation system to ensure air exchange but only dynamically suck in a minimum of warm outside air. The ventilation system detects air pollutants (e.g., from cooking) and filters odors as quickly as possible, deciding autonomously what action to take.
The shading system continuously adjusts the roller shutter slats to minimize heat gain without darkening rooms excessively to avoid disturbing residents. The weather station reports the current solar intensity on the sun-facing facades. As a last measure, the air conditioning is on standby and cools the rooms if thermostats signal a need. The air conditioning turns off when windows or doors remain open for extended periods. Hot water is heated and stored by solar panels.
When away or taking a nap, the house maximizes shading/darkening and minimizes ventilation. Other systems remain unaffected and maintain temperature and other conditions at the desired level. Presence, absence, and sleep are detected by additional sensors and reported to the systems.
In winter, everything works the opposite way. There is little shading to capture as much as possible of the sun’s “free energy.” Ventilation is continuously adjusted to current conditions. Windows generally remain closed. The air conditioning and summer bypass are off.
The system also detects when someone showers and increases exhaust ventilation to remove moisture quickly.
The system is calibrated enough for us to do without a separate energy recovery ventilator (ERV). Mostly, this is due to outdoor temperature-controlled boiler management and natural self-regulation rather than the advanced control itself.
Roller shutter control:
As mentioned, shading is a major part. Additionally, there are various scenarios, usually executed automatically but also manually triggered.
The roller shutters are continuously informed by sensors about the current situation, such as solar intensity, window position (open/closed/tilted), indoor and outdoor temperatures, and whether anyone is home. From this, the shutters calculate the optimal position.
For example, shutters open in the morning and close in the evening. It’s not simply about light or dark outside but also the time of day and the season. In winter, some shutters stay open longer in the evening to allow Christmas lights. They close only when residents decide to go to bed.
There is an extra safety mechanism at the patio door: as long as it is open, the shutter stays up. Generally, whenever a window opens, the shutter rolls up. Closing the window causes the shutter to lower again unless it is already light outside or shading is needed, in which case the shutter moves to the last used position. If the door is closed but people remain outside longer than a preset delay, another condition applies: as long as the patio light is on, the shutter remains up. This makes being locked out nearly impossible.
The advantage: you don’t have to worry about the shutters. They are always in the right position and require no manual intervention. If you want to go outside and the shutter is down, simply open the door.
Lighting and shadows:
In all non-living areas such as the kitchen, bathroom, hallways, etc., presence detectors switch lights on and off slowly or quickly depending on the situation and required lighting. Constant measurements determine current conditions and whether light is needed at all. Different rules apply during the day versus evening or night, adjusting brightness accordingly. The house “knows” when occupants are sleeping, so lights come on dimmed in the morning. Also, shutters in bedrooms stay down until a certain time during sleep, and the doorbell is disabled during that time.
Here you can see again how everything works together.
Since we have two cats, we couldn’t automate everything further and had to forgo popular presence detectors under the bed.
We also have predefined lighting scenes like cinema, dinner, or watching TV. These create lighting moods according to our preferences, for instance, dimming the room when the projector is turned on or activating subtle LED lighting while watching TV.
Hallways, entrance, utility room, and guest WC have small light switches. Everything runs automatically, guests manage easily, and explanations are rarely needed.
Extras:
Thanks to advanced electrical systems, we also have neat little features impossible with conventional wiring. For example, there’s a sensor in the mailbox that detects when mail arrives. The coffee machine in the downstairs kitchen turns on automatically in the morning (during a defined time) and makes fresh coffee.
Other small features:
- Presence simulation (a daily routine is mimicked, not just mindless on/off switching of lights)
- Alarm system (makes the house flash wildly in an alarm event)
- Motion alarms and doorbell notifications sent to phones
- Motorized lock
- Garden irrigation
- Central on/off control (at multiple points in the house and online)
- Various statistics and graphical displays of temperature trends, etc.
- Consumption measurements
- Leak detectors
- Individual socket power consumption with simple logic
- Garbage calendar with notifications for the correct bin the day before
- Visualization of the system and remote access
etc.
Why all this? Well, the reasons vary. First and foremost, it saves some time since you don’t have to operate light switches or shutters manually. Everything becomes a bit more convenient. You don’t need to perform five steps to watch a movie; just turn it on, and the house handles the rest.
It also provides a sense of increased security through status messages on the phone or presence simulation. Of course, it also saves some operating costs, which are then somewhat offset by the additional sensors and devices. Appetite grows with eating, and the system usually ends up getting expanded over time as new desired functions appear.
By the way, our system with about 80 participants/devices consumes a modest 20W of electricity. But there’s no end in sight – for Christmas, I bought a home server. Until then, a Raspberry Pi served as the gateway to the outside world and for visualization.
I probably forgot a lot, but that’s enough text for now, don’t you think?
Here are a few pictures to relax:
However, I don’t have a basic setup nor a high-end cabin with all the bells and whistles.
I would say it’s more like upper mid-range.
With 10,000 you could implement quite a bit of what was described in the original post. Essentially a basic automation system.
Some lighting and shading, a few power outlets. Here and there a gadget and a weather station. Possibly some heating control. That’s enough to get started and live a bit more comfortably without significant extra costs. And since you have the basic framework, you can expand it later.
I would say it’s more like upper mid-range.
With 10,000 you could implement quite a bit of what was described in the original post. Essentially a basic automation system.
Some lighting and shading, a few power outlets. Here and there a gadget and a weather station. Possibly some heating control. That’s enough to get started and live a bit more comfortably without significant extra costs. And since you have the basic framework, you can expand it later.
Thank you for your assessment. I’m curious to find out the additional cost involved in implementing the star topology wiring and relocating the electrical panel. I plan to handle the KNX components and programming myself, including commissioning.
I will also do the network and satellite cabling on my own.
Depending on whether I am allowed or able to chase channels in the walls, I would of course like to install additional KNX cables that aren’t immediately necessary in the first phase. How did you approach this? Running a loop around the center of the room? Connecting possible switches but not installing them yet (with or without back boxes)?
I will also do the network and satellite cabling on my own.
Depending on whether I am allowed or able to chase channels in the walls, I would of course like to install additional KNX cables that aren’t immediately necessary in the first phase. How did you approach this? Running a loop around the center of the room? Connecting possible switches but not installing them yet (with or without back boxes)?
No center of the room or anything like that—that’s too much effort.
Simply drill all the boxes that will be needed immediately as well as those that might be planned for the future. Then just lay the bus cable in loops, one after another. You will use more bus cable this way, but that’s not a big expense.
So, run the cable into the box and back out again to the next one. If the box is needed, cut the cable inside it and insert a KNX connector. If it’s not needed (for now), leave the cable continuous without unnecessary joints.
Otherwise, I just ran extra cables to all the possible corners and so on, which were then connected to the line if needed.
For example, in multiple locations in the attic, mailbox, gate and garden door, carport, several spots in the garden, tool shed, etc. Bit by bit, some of these were connected and others were not.
Simply drill all the boxes that will be needed immediately as well as those that might be planned for the future. Then just lay the bus cable in loops, one after another. You will use more bus cable this way, but that’s not a big expense.
So, run the cable into the box and back out again to the next one. If the box is needed, cut the cable inside it and insert a KNX connector. If it’s not needed (for now), leave the cable continuous without unnecessary joints.
Otherwise, I just ran extra cables to all the possible corners and so on, which were then connected to the line if needed.
For example, in multiple locations in the attic, mailbox, gate and garden door, carport, several spots in the garden, tool shed, etc. Bit by bit, some of these were connected and others were not.
Mycraft schrieb:
Then simply lay the bus cable in loops one after the other. Do you mean just leaving 10–20cm (4–8 inches) of cable in each outlet as spare, laid in loops one after the other?
Well, not into every single box but into each group of boxes. Essentially, you run one cable into the room, connect it in series from one box group to another in one continuous length, and then either proceed to the next room or finish and repeat the same process in the other room with a new cable run.