ᐅ Electrical Planning: What to Consider? Process, Explanations, and Tips
Created on: 20 Aug 2013 19:55
E
Elektro1Hello dear forum community,
I am often surprised to see that many homeowners do not put much thought into the electrical planning of their new homes (of course, there are exceptions). Yet, the electrical system is the hidden core of any house.
A bit about me and my background:
I am a trained industrial electrician specializing in operational technology, with a master craftsman certificate in electrical trades. Although I work primarily in industry, I am confident I can handle planning the electrical system for a single-family house. 🙂
What do I want to achieve?
With this thread, I want to help those who lack knowledge a little bit. On one hand, I will explain some basic concepts; on the other, I will offer valuable planning tips. And once I finish the text, I’m looking forward to any discussions that may arise.
A quick note beforehand:
I tend to type quickly and often miss my own mistakes. I’m not very keen on proofreading my posts, so please forgive any typos. I try to follow a rough order in my explanations, but I don’t have a formal structure, so I might jump around in the text. Sorry in advance for that, but I don’t really feel like writing a full guideline.
Enough talking, let’s get started:
I am often surprised to see that many homeowners do not put much thought into the electrical planning of their new homes (of course, there are exceptions). Yet, the electrical system is the hidden core of any house.
A bit about me and my background:
I am a trained industrial electrician specializing in operational technology, with a master craftsman certificate in electrical trades. Although I work primarily in industry, I am confident I can handle planning the electrical system for a single-family house. 🙂
What do I want to achieve?
With this thread, I want to help those who lack knowledge a little bit. On one hand, I will explain some basic concepts; on the other, I will offer valuable planning tips. And once I finish the text, I’m looking forward to any discussions that may arise.
A quick note beforehand:
I tend to type quickly and often miss my own mistakes. I’m not very keen on proofreading my posts, so please forgive any typos. I try to follow a rough order in my explanations, but I don’t have a formal structure, so I might jump around in the text. Sorry in advance for that, but I don’t really feel like writing a full guideline.
Enough talking, let’s get started:
For Safety
The RCD
The RCD (Residual Current Device) is a personal protection switch designed for your safety.
It is standard to install one rated at 40A, 30mA.
40A is the maximum current that may flow through the RCD, and 30mA is the maximum leakage current at which it must trip.
An RCD with a rating above 30mA is not permitted.
One RCD for the entire house is not sufficient; do not be misled by your electrician.
A practical distribution would be, for example:
1 RCD for the sockets
1 RCD for the lighting
1 RCD for home technology
1 RCD for refrigeration units
1 RCD for outdoor areas including the garage/carport
Why all this effort?
If you only have one RCD and a fault occurs, you will be in the dark across your entire property. That is very inconvenient.
By separating sockets and lighting, at least some lights will still work.
The outdoor area should also always have its own RCD, as moisture can cause faults.
An RCD for home technology and refrigeration units is not absolutely necessary, but for example, it offers a significant advantage for your frozen goods during summer vacations if the sockets in the living room fail; the same applies in winter for heating.
For permanently installed appliances (those not connected via a socket), no RCD is required.
Circuit Breakers
Circuit breakers protect the connected wiring from overloads, preventing them from overheating or causing damage. They do not offer personal protection (which is the function of the RCD).
In residential applications, miniature circuit breakers (MCBs) with a B characteristic curve are used. The "B" refers to the trip curve behavior, typically 5 times the rated current (5xIn).
Example 1:
If a 16A breaker is installed and a short circuit occurs, a total current of 5x16A = 80A flows, causing the breaker to trip immediately.
Example 2:
If you puncture but only lightly damage the cable, causing leakage currents between line and neutral below 5x16A, the breaker will not trip immediately but will heat up and trip after a short time.
The "B" characteristic defines this timing, which can be read from standard charts. This time delay is why circuit breakers are not approved for personal protection.
Sizing of Circuit Breakers.
Circuit breakers should at least match the cross-sectional area of the wiring behind them, but ideally, they should also be matched to the application.
For example, I use 16A breakers for sockets and 6A or 10A breakers for indoor lighting.
The reason for this differentiation is the aforementioned trip time.
A maximum of 10 sockets per 16A breaker is recommended. This is related to the diversity factor.
I learned that, on average, 300W is drawn per socket. A 16A breaker can handle 3000W, so 10 sockets per circuit is reasonable.
Each room should be protected by its own breaker. A breaker costs about 1.00€ retail, so do not let anyone charge you significantly more. Keep in mind that this also means each room will have a separate cable feed.
The same applies to lighting: one breaker per room. Usually, this is enough unless you plan to install high-power spotlights up to 1000W.
Large appliances, such as washing machines, dryers, refrigerators, dishwashers, ovens, cooktops, coffee machines, etc., should have their own dedicated breaker.
Especially devices over 2kW rating. For devices above 3kW (such as instantaneous water heaters), a 16A breaker is no longer sufficient, and the supply cable must also be sized accordingly.
As you can see, this adds up. Therefore, you should plan a larger main electrical panel for your house from the start.
Having an extra empty meter slot can also be advantageous for future upgrades (heat pump or photovoltaic system).
The RCD
The RCD (Residual Current Device) is a personal protection switch designed for your safety.
It is standard to install one rated at 40A, 30mA.
40A is the maximum current that may flow through the RCD, and 30mA is the maximum leakage current at which it must trip.
An RCD with a rating above 30mA is not permitted.
One RCD for the entire house is not sufficient; do not be misled by your electrician.
A practical distribution would be, for example:
1 RCD for the sockets
1 RCD for the lighting
1 RCD for home technology
1 RCD for refrigeration units
1 RCD for outdoor areas including the garage/carport
Why all this effort?
If you only have one RCD and a fault occurs, you will be in the dark across your entire property. That is very inconvenient.
By separating sockets and lighting, at least some lights will still work.
The outdoor area should also always have its own RCD, as moisture can cause faults.
An RCD for home technology and refrigeration units is not absolutely necessary, but for example, it offers a significant advantage for your frozen goods during summer vacations if the sockets in the living room fail; the same applies in winter for heating.
For permanently installed appliances (those not connected via a socket), no RCD is required.
Circuit Breakers
Circuit breakers protect the connected wiring from overloads, preventing them from overheating or causing damage. They do not offer personal protection (which is the function of the RCD).
In residential applications, miniature circuit breakers (MCBs) with a B characteristic curve are used. The "B" refers to the trip curve behavior, typically 5 times the rated current (5xIn).
Example 1:
If a 16A breaker is installed and a short circuit occurs, a total current of 5x16A = 80A flows, causing the breaker to trip immediately.
Example 2:
If you puncture but only lightly damage the cable, causing leakage currents between line and neutral below 5x16A, the breaker will not trip immediately but will heat up and trip after a short time.
The "B" characteristic defines this timing, which can be read from standard charts. This time delay is why circuit breakers are not approved for personal protection.
Sizing of Circuit Breakers.
Circuit breakers should at least match the cross-sectional area of the wiring behind them, but ideally, they should also be matched to the application.
For example, I use 16A breakers for sockets and 6A or 10A breakers for indoor lighting.
The reason for this differentiation is the aforementioned trip time.
A maximum of 10 sockets per 16A breaker is recommended. This is related to the diversity factor.
I learned that, on average, 300W is drawn per socket. A 16A breaker can handle 3000W, so 10 sockets per circuit is reasonable.
Each room should be protected by its own breaker. A breaker costs about 1.00€ retail, so do not let anyone charge you significantly more. Keep in mind that this also means each room will have a separate cable feed.
The same applies to lighting: one breaker per room. Usually, this is enough unless you plan to install high-power spotlights up to 1000W.
Large appliances, such as washing machines, dryers, refrigerators, dishwashers, ovens, cooktops, coffee machines, etc., should have their own dedicated breaker.
Especially devices over 2kW rating. For devices above 3kW (such as instantaneous water heaters), a 16A breaker is no longer sufficient, and the supply cable must also be sized accordingly.
As you can see, this adds up. Therefore, you should plan a larger main electrical panel for your house from the start.
Having an extra empty meter slot can also be advantageous for future upgrades (heat pump or photovoltaic system).
Basics of Electrical Planning
Standard installations in construction work are never sufficient!
If you don’t customize them, you will regret it sooner or later.
Your electrical planning should be as generous as possible.
Later modifications are annoying, laborious, messy, and expensive.
It’s better to spend a little less on the switch series (I know, glass frames look great, but please no cheap hardware store stuff) and invest more in additional sockets, switches, light outlets, etc.
Sockets:
You can never have enough!
I personally dislike power strips (although sometimes they are unavoidable). Not only can cheap ones be fire hazards, but they also take up space behind furniture or are constantly in the way.
Personally, I recommend installing at least two sockets wherever you plan to have one.
The extra effort for the electrician might be only about 10 minutes more, material cost roughly 5€, electrician’s hourly rate ~40€, so it costs around 6€ to install. So an additional socket in the standard series should not cost more than about 15€.
Sockets should be planned at every window, so you are prepared for any seasonal decorations or window enhancements.
Think about where your cabinets will go and include sockets there for cabinet lighting.
Install a socket under every switch group (note that the largest frame can hold a maximum of 5 elements).
Wherever a television is planned, at least 2, ideally 3, sockets should be installed. Reason: TVs are getting thinner and sound quality is often poor, so soundbars are increasingly used, already taking up 2 sockets. The third socket is for backup or a media box (e.g., Apple TV).
This group of sockets should be switchable on and off via a separate switch (electricity costs will continue to rise).
Don’t be stingy with sockets in the kitchen either. Consider which appliances you usually keep on the countertop (toaster, coffee machine, small electric grill, etc.). These sockets are already allocated. Additionally, plan 2 free sockets per countertop section. Sockets on a kitchen island are also very convenient—do you really want to run an extension cord with a power strip across your kitchen?
In the bedroom, have at least 2 sockets on each bedside: 1 for a lamp, 1 for charging phones or similar devices. If you want a TV in the bedroom, as mentioned before, plan for the switch to be accessible both at the bed and at the door. If there are 4 or more switches, an impulse relay (latching relay) is needed for the circuit. Before the electrician tries to install an expensive relay in the distribution board (which requires more wiring and work), inform them that such a relay can also be placed in the switch box.
In the bathroom, sockets must not be installed within wet zones.
The Media Center
Today, almost every household will have a media center somewhere, usually in the living room. This includes TVs, AV receivers, game consoles, media boxes, Blu-ray players, subwoofers, universal remote chargers, etc.
That adds up to 7 sockets, and a few more (3) as backup never hurts.
Keep in mind: 10 sockets usually correspond to one 16A fuse.
This entire group should be switchable on and off from a central point.
In addition to these sockets, plan speaker connection outlets for a 5.1 surround system (especially if you don’t want cables strewn across the room) and at least 2 network (Ethernet) sockets (the first 5 devices will generally need one).
Speaker outlets don’t have to be expensive via the switch series—just a frame and base plate from the standard series, plus some banana plug connectors from an electronics store, are enough to save over 50% on costs with a little skill.
Exterior sockets on the house wall should be switchable from inside and must have a cover. Make sure these sockets are suitable for outdoor use (correct IP rating).
Light Fixtures / Light Switches
Plan light fixture points as you see fit.
Each separate light fixture should have its own switch.
For multiple switch locations: from 4 switches onward, an impulse relay is required. This does not necessarily have to be installed in the distribution board; a more cost-effective version is a relay for the switch box.
In hallways, it should be possible to control the light from every door. Motion sensors are an elegant solution here (especially when arriving home with hands full).
In passage rooms, lights should also be controllable from every door (e.g., from the garage to the utility room).
To keep the switch panel from getting too large, multi-gang switches can be used (2 switches in one frame).
I like having light fixture points at the bed, it saves me a socket.
In addition, room lighting should be able to be turned off from the bed.
Furniture lighting: carefully consider whether you need to buy the lighting offered with your furniture purchase. Usually, it is overpriced. Electronics stores offer similar lighting at much lower prices. With LED strip lights, very nice and cost-effective solutions can be created.
House lighting does not only look good; it also deters unwanted guests. Therefore, install a switch inside that allows you to choose between continuous light or activation by motion sensors. To avoid lighting up all areas when someone walks past, motion sensors can be installed at each side of the house. However, this kind of setup entails a sometimes considerable extra effort.
Standard installations in construction work are never sufficient!
If you don’t customize them, you will regret it sooner or later.
Your electrical planning should be as generous as possible.
Later modifications are annoying, laborious, messy, and expensive.
It’s better to spend a little less on the switch series (I know, glass frames look great, but please no cheap hardware store stuff) and invest more in additional sockets, switches, light outlets, etc.
Sockets:
You can never have enough!
I personally dislike power strips (although sometimes they are unavoidable). Not only can cheap ones be fire hazards, but they also take up space behind furniture or are constantly in the way.
Personally, I recommend installing at least two sockets wherever you plan to have one.
The extra effort for the electrician might be only about 10 minutes more, material cost roughly 5€, electrician’s hourly rate ~40€, so it costs around 6€ to install. So an additional socket in the standard series should not cost more than about 15€.
Sockets should be planned at every window, so you are prepared for any seasonal decorations or window enhancements.
Think about where your cabinets will go and include sockets there for cabinet lighting.
Install a socket under every switch group (note that the largest frame can hold a maximum of 5 elements).
Wherever a television is planned, at least 2, ideally 3, sockets should be installed. Reason: TVs are getting thinner and sound quality is often poor, so soundbars are increasingly used, already taking up 2 sockets. The third socket is for backup or a media box (e.g., Apple TV).
This group of sockets should be switchable on and off via a separate switch (electricity costs will continue to rise).
Don’t be stingy with sockets in the kitchen either. Consider which appliances you usually keep on the countertop (toaster, coffee machine, small electric grill, etc.). These sockets are already allocated. Additionally, plan 2 free sockets per countertop section. Sockets on a kitchen island are also very convenient—do you really want to run an extension cord with a power strip across your kitchen?
In the bedroom, have at least 2 sockets on each bedside: 1 for a lamp, 1 for charging phones or similar devices. If you want a TV in the bedroom, as mentioned before, plan for the switch to be accessible both at the bed and at the door. If there are 4 or more switches, an impulse relay (latching relay) is needed for the circuit. Before the electrician tries to install an expensive relay in the distribution board (which requires more wiring and work), inform them that such a relay can also be placed in the switch box.
In the bathroom, sockets must not be installed within wet zones.
The Media Center
Today, almost every household will have a media center somewhere, usually in the living room. This includes TVs, AV receivers, game consoles, media boxes, Blu-ray players, subwoofers, universal remote chargers, etc.
That adds up to 7 sockets, and a few more (3) as backup never hurts.
Keep in mind: 10 sockets usually correspond to one 16A fuse.
This entire group should be switchable on and off from a central point.
In addition to these sockets, plan speaker connection outlets for a 5.1 surround system (especially if you don’t want cables strewn across the room) and at least 2 network (Ethernet) sockets (the first 5 devices will generally need one).
Speaker outlets don’t have to be expensive via the switch series—just a frame and base plate from the standard series, plus some banana plug connectors from an electronics store, are enough to save over 50% on costs with a little skill.
Exterior sockets on the house wall should be switchable from inside and must have a cover. Make sure these sockets are suitable for outdoor use (correct IP rating).
Light Fixtures / Light Switches
Plan light fixture points as you see fit.
Each separate light fixture should have its own switch.
For multiple switch locations: from 4 switches onward, an impulse relay is required. This does not necessarily have to be installed in the distribution board; a more cost-effective version is a relay for the switch box.
In hallways, it should be possible to control the light from every door. Motion sensors are an elegant solution here (especially when arriving home with hands full).
In passage rooms, lights should also be controllable from every door (e.g., from the garage to the utility room).
To keep the switch panel from getting too large, multi-gang switches can be used (2 switches in one frame).
I like having light fixture points at the bed, it saves me a socket.
In addition, room lighting should be able to be turned off from the bed.
Furniture lighting: carefully consider whether you need to buy the lighting offered with your furniture purchase. Usually, it is overpriced. Electronics stores offer similar lighting at much lower prices. With LED strip lights, very nice and cost-effective solutions can be created.
House lighting does not only look good; it also deters unwanted guests. Therefore, install a switch inside that allows you to choose between continuous light or activation by motion sensors. To avoid lighting up all areas when someone walks past, motion sensors can be installed at each side of the house. However, this kind of setup entails a sometimes considerable extra effort.
If you plan to install roller shutters, arrange for a central timer to control them. Additionally, you can install individual roller shutter switches at each window, although this is not necessarily required if you have a central timer (note: if you only have the timer, you cannot operate the shutters individually).
I usually plan for one timer per floor.
Have the window manufacturer supply only the manual roller shutters; purchase the motors yourself online. Rademacher is one of the top manufacturers, also offering a secondary brand with up to 10 years warranty and significantly lower prices.
Pay attention to the key size of the roller shaft inside the box and to the weight.
Network, Telephone, and TV
Plan network outlets wherever TV, PC/MAC, laptop, router, etc. will be placed.
A telephone connection is sufficient nowadays in the utility room; hallways and bedrooms can also be sensible locations. If you have planned enough network outlets, these can easily be converted to telephone outlets if needed.
Please use only CAT7 cables; anything older is almost outdated. CAT7 should not be significantly more expensive.
You might be able to save on the network outlets themselves.
Example: Gira offers network outlets with covers, and they also provide standard covers that fit network outlets from other manufacturers, such as Telegärtner. This can yield around 30% savings.
Other manufacturers have similar options. Your electrician should be aware of this.
No need to say much about TV, right?
The cables used (CAT7, antenna cable) must be installed in protective conduits flush-mounted or in/under the screed. In the attic or generally surface-mounted, the cable can be laid openly and fixed with nail clips.
So, I hope I haven’t forgotten too much in the electrical planning and will conclude this topic for now. Next, we will proceed with the electrical installation.
P.S. Power outlets in the workspace area (desk): PC, monitor, speakers, printer, scanner (5 units, controlled by a switch)
I usually plan for one timer per floor.
Have the window manufacturer supply only the manual roller shutters; purchase the motors yourself online. Rademacher is one of the top manufacturers, also offering a secondary brand with up to 10 years warranty and significantly lower prices.
Pay attention to the key size of the roller shaft inside the box and to the weight.
Network, Telephone, and TV
Plan network outlets wherever TV, PC/MAC, laptop, router, etc. will be placed.
A telephone connection is sufficient nowadays in the utility room; hallways and bedrooms can also be sensible locations. If you have planned enough network outlets, these can easily be converted to telephone outlets if needed.
Please use only CAT7 cables; anything older is almost outdated. CAT7 should not be significantly more expensive.
You might be able to save on the network outlets themselves.
Example: Gira offers network outlets with covers, and they also provide standard covers that fit network outlets from other manufacturers, such as Telegärtner. This can yield around 30% savings.
Other manufacturers have similar options. Your electrician should be aware of this.
No need to say much about TV, right?
The cables used (CAT7, antenna cable) must be installed in protective conduits flush-mounted or in/under the screed. In the attic or generally surface-mounted, the cable can be laid openly and fixed with nail clips.
So, I hope I haven’t forgotten too much in the electrical planning and will conclude this topic for now. Next, we will proceed with the electrical installation.
P.S. Power outlets in the workspace area (desk): PC, monitor, speakers, printer, scanner (5 units, controlled by a switch)
So, I will conclude my presentation here.
In closing, it should be noted that my explanations are neither exhaustive nor complete.
I have compiled this presentation to the best of my knowledge and belief. However, it has no validity apart from the standards and regulations set out in the DIN VDE and the recognized rules of technology.
In closing, it should be noted that my explanations are neither exhaustive nor complete.
I have compiled this presentation to the best of my knowledge and belief. However, it has no validity apart from the standards and regulations set out in the DIN VDE and the recognized rules of technology.
Similar topics