Electrical, Home, Repairs

How to upgrade an electrical system

upgrade an electrical system

Can I upgrade an electrical system myself? Refurbishing obsolete electrical installations is one of the more complex tasks when renovating. A great deal of technical know-how is sometimes necessary. We show you what you can do yourself and what you have to pay attention to.

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In order to maintain the value of a property, it is necessary to carry out various repair and renovation work at regular intervals. The electrical installations play a special role here.

On the one hand, cables and switches are subject to normal wear. On the other hand, modern devices and other electrical consumption points today place different requirements on the installations than in the past.

In addition to replacing power guzzlers , energy can often be saved through renewal. The power grid for supplying the household is usually invisible. This makes renovation all the more complex. Technology is also becoming increasingly complex. Anyone who lends a hand must pay attention to many different points.

Upgrade an electrical system: the basis for correct planning

If the electrical installations are to be completely renewed, solid planning is essential. Because renewal involves so much effort, old lines or sockets are not replaced as often as would be necessary.

In many older houses, the installations have not been changed since they were installed. It is often unaware that this is a major security risk. Broken cables or overloading can lead to short circuits and cable fires.

In addition, various new regulations have been issued today to increase security. In order to avoid adequate protection against overvoltage and to equip the complex system of cables and connections appropriately for today, certain basics should be observed.

Determine the need

The number of electrical devices that we use in daily use has increased significantly in recent years. Private households use around ten times more electricity today than 50 years ago. Especially in this point, the age-old pipeline system usually shows major deficits. It is simply not designed for the many consumption points.

The lack of necessary sockets is then often compensated for with multiple socket strips. But even these can quickly become overloaded and become a danger. If the maximum possible power is exceeded, a fire can also occur.

In a first step to upgrade an electrical system, the necessary needs should therefore first be analyzed. This is based primarily on the individual usage habits and the existing or planned electronic devices. The following consumption points should be included in the planning:

  • Fixed lighting as well as lighting connected via sockets
  • Connection options for fixed devices such as a refrigerator, extractor hood or washing machine
  • Sufficiently dimensioned connections for stove, hob, gas boiler, hot water tank or other heating devices (if necessary,  high current )
  • Connection options for devices for communication or entertainment electronics (additional communication connections may be necessary for reception)
  • Sufficient sockets for mobile devices such as kettles, toasters, chargers or the vacuum cleaner
  • Connectivity   options outdoors

Use floor plans

In order to visualize the planning, a schematic representation has proven itself, in which the individual installations are entered room by room. Based on the floor plan, the exact positions for the lines and connections are recorded. The concept remains clear and no important positions are forgotten.

Symbols are used for the various electrical components. This means that the plan remains manageable, even if several installation elements are close together. The characters may look a bit cryptic at first glance, but usually only the most common ones are needed.

Those who deal with it a little will soon have the most important abbreviations in their heads and can easily read or add to the plans.

In addition to the floor plans, it is also useful to create wall views for exact position determination when you upgrade an electrical system. This makes it possible to determine and record the exact course of cables or the height of sockets and connections. In contrast to the past, various rules ensure that the cables are no longer pulled back and forth across the walls. This makes it easier to avoid the electrical cables later when drilling.

 It is especially sensible to always pull the cables at right angles and to take into account the specified and proven distances to other installations.

Power plans

It is an advantage if the placement of various pieces of furniture has already been determined. Nevertheless, a possible change in use should also be taken into account. Adequate sockets or an additional TV connection at another location ensure a certain degree of flexibility.

If it is clear which individual fixtures should be placed in the different rooms, the basic power distribution can be planned. The central power box is usually located near the house connection. The electricity meter is also located there.Incidentally, digital electricity meters will be mandatory for households that exceed a certain annual consumption of electricity. If the electrical installations are being renovated anyway, this is the right time to check the installation of such a meter. Critics complain about the new devices that personal data on electricity consumption and usage behavior is collected and forwarded.

A sub-distribution box is usually added to the main connection, which is usually located on the ground floor of a house and on the respective floors for flats. The dimensioning is based on the size of the apartment and the scope of the individual consumption points.

From here, the various lines and circuits are placed in all rooms. In addition, timers or controllers for controlling the automatic staircase lighting can also be accommodated there. The following processes must be observed:

  • Relocation (renewal) of the risers is best in the area of ​​the corridors
  • Sufficient fire protection for the new risers
  • Positioning the electrical box for the sub-distribution at a central point branch lines to the individual rooms through the walls
  • Laying the cables in the rooms under plaster, in drywall, in a baseboard channel or in a suspended ceiling

Use supply shafts and empty pipes for wires

In order to keep the interference in the load-bearing structure of the walls and ceilings as low as possible, empty pipes or cable ducts are used for the cables to bridge longer distances. There are various ways of restructuring the installations or making good use of old installations:

  • Use a central cable duct: In order to be able to lay more cables later with less effort, it makes sense to provide a larger cable duct in a central location, for example in the hallway. From there, short sections can usually be easily guided through a hole in the wall into the individual rooms.
  • Use unused chimneys : In older buildings, there are often several chimneys. Due to the modern central heating, not all of them are usually used. They are usually large enough to accommodate a few cables and are often in a convenient location. In addition, they are already adequately equipped for fire protection. If in doubt, the chimney sweep can be asked for advice on which shaft could be used.
  • Plan for additional empty pipes : To make it easier to manage changes or changes in the rooms, it makes sense to provide empty pipes in the wall at other suitable locations. Then the plaster does not have to be pried open again when laying a new line.

Plan for multiple circuits Shorter cables and circuits are safer than continuous cables from the basement to the point where the source of consumption is located. Therefore it makes sense to install an electrical box in the apartment. There, the individual circuits are protected separately from one another. There are also several points to consider here:

  • Plan separate circuits : It makes sense to provide separate circuits for the individual consumer points. For example, lighting, sockets or communication lines should be installed separately. When several devices are operated at the same time, the power load is better distributed.
  • Adjust the number of circuits to suit your needs : Depending on the size of the apartment and the number of required points of consumption, a minimum number of separate circuits has been established today. The recommendations are based on the usual basic equipment. Additional installations such as solar systems or security and comfort technology (Smart Home) require additional separately secured cable routes.    

Upgrade an electrical system: Use correct protection

Depending on the type of circuit, the appropriate fuse must be installed. Devices with high consumption, such as electric cookers, require greater protection than circuits for energy-saving LED lighting. A basic distinction is made between several different fuse switches:

  • Main fuse (SLS switch): Instead of the usual fuses, the modern selective circuit breakers are now used. They are still in front of the electricity meter and ensure that the line network is switched off if the other fuses fail.
  • RCD (residual current circuit breaker): This switch detects residual currents, such as those that occur in the event of a short circuit or when people come into contact with a live cable. The connection is then interrupted within a few milliseconds. The switch can be turned on again after the source of the error has been rectified. Usually, several circuits are additionally protected by the FI switch. 
  • Circuit breaker: This protects the electrical lines of the individual circuits. It is also used to switch off fault currents and can be reused.
  • Fire protection switch: This checks the line system for fluctuations in the voltage curve and protects against arcing faults. They are used in low-voltage installations and are mandatory in certain, particularly fire-prone areas in new buildings.
  • Fuses (NH fuses): These should be replaced as part of the renovation work. Today, they are only installed for permanently installed devices such as instantaneous water heaters. Once triggered, the screwed-in fuse must be replaced with a new one. different approaches have proven themselves. With the angle grinder or a special wall chaser, the necessary width has already been determined and the masonry does not break out again when it is finally removed.

Construction measures

If the planning has been carried out properly and in accordance with today’s standards, the work can be carried out on this basis. If time-consuming tasks such as slitting or pulling cables are done by yourself, this can significantly reduce the burden on the household budget.

Rerouting wires

In places where there are no empty pipes or cable ducts, the lines are usually concealed. Sufficiently large slots are cut into the masonry or the respective wall and ceiling material.

In this case , the following methods have been proven . With the angle grinder or a special wall chaser, the necessary width has already been determined and the masonry does not break out again when it is finally removed.

Before starting work, it is important to ensure that no other installations can be damaged or cut and that the correct milling depth is taken into account. The cables themselves should be of sufficient length at the beginning and end for the respective connection. They are fastened in the wall groove with special nails or clamps and then filled with plaster.

Sockets and switches

Holes are prepared for sockets or switches with a suitable drill and the appropriate drill heads. If there are several cans next to or one below the other, it is advisable to use a template so that the holes are in a straight line.

The hollow boxes for switches and sockets are also fixed with a small dab of plaster. It is important to pull the connecting cable to the front beforehand. The holding claws of some inserts often hold poorly in the cavity wall boxes. It is better to use side screws for fixing. No live cables may be damaged.

After the cables have been connected correctly, a small screw in the middle is usually provided for attaching the socket inserts. Switches, on the other hand, only have plastic nipples that snap into the counterpart on the wall – done. After connection, a phase tester can be used to test whether the cables are live at the place of use.

Lay telecommunication lines

Connections for telephone, internet or television reception are often also set up outside of renovation measures. Depending on which provider is used, new lines must then be installed. The main connection also requires a certain amount of space, which must be kept free in the basement near the other facilities.

Empty conduits that are still unused prove to be very helpful for the additional cables. The thicker cables are more rigid and cannot be easily pushed through the narrow openings. If a data distributor is provided centrally in the house or apartment, the individual connections can be made from there.

In the case of new buildings, separate control cabinets for a comprehensive network in the house are now common. Similar to the power supply, the distribution of the lines in the individual rooms can be done.

The actual connection often has to be carried out by the respective communication company. A technician will come by at the latest to activate the cables to check the cables and ensure that they function properly.  

Observe standard distances and right angles

The laying rules should also be observed for cables that are laid in the cavity of walls, ceilings or in the floor. Always pulling the cable at a right angle and taking into account the recommended minimum distances from other installations is also valid here. If you later have to drill into the wall to attach a dowel, you have reliable clues as to which areas are taboo.

It is also advisable when you upgrade an electrical system, to use empty pipes for ceilings and drywall, as the places are usually difficult to access or additionally filled with insulation material.

Take special note of damp rooms and heavy current

In order to protect the electrical connections from moisture, special installation items are available for the bathroom or kitchen. In damp-proof sockets, for example, the opening is additionally closed by a hinged cover.

Care should also be taken to ensure that the lighting is moisture-resistant. Otherwise, cables or lamps are quickly threatened by oxidation and must be constantly replaced.

Even if many hobs or ovens no longer require a high-voltage connection today, it makes sense to provide such a connection in the line system. The connections for these points of consumption are more secure than the other circuits because they are exposed to greater loads.

For other devices that require a lot of electricity, such as various water heaters or storage tanks, special approval from the local electricity supplier may be necessary. The performance of the entire system is checked to avoid overloading the system.

Upgrade an electrical system: further tips

The most important rule first : When working on cables and electrical systems, the electricity should be switched off. So there is no risk of electric shock even if you accidentally touch cables or connectors. The other tips help to avoid common mistakes:

  • Note cable cross-sections:  Different thickness cables are required for different consumers: 1.5 mm² for switches, sockets and lights and 2.5 mm² for hob, oven and other devices with high power consumption. An FI socket , for example, ensures greater safety in the bathroom due to the higher moisture levels. 
  • An FI socket , for example, ensures greater safety in the bathroom due to the higher moisture levels. 
  • In the outdoor special cables must be used with a special insulation. These underground cables can then be laid directly in the ground without an empty conduit. Sockets and switches must also be equipped to withstand moisture and weather influences.
  • Multiple sockets are also available with the appropriate built-in overload protection. If there are too few connections despite good planning, the investment in security is worthwhile.
  • Documenting installations photographically: In addition to electrical planning, it makes sense to photograph the walls with the corresponding new cables and connections. Ideally with a tape measure or yardstick with in the picture. Then you can later understand exactly where the installations are going.
  • Seek help from professionals: If uncertainties arise when installing the electrical installations, professional support from professionals should be sought in any case to upgrade an electrical system. In addition, acceptance of the finished system by a certified electrician also offers a guarantee. In the event of damage, the relevant document can save the insurance company a lot of trouble.

gerhardt-richter Gerhardt Richter is a writer and a trainer at trade technical colleges, specializing in carpentry, plumbing, mechanics and construction.