How do you Protect your Home's Electrical Installation?
HomeHome > News > How do you Protect your Home's Electrical Installation?

How do you Protect your Home's Electrical Installation?

Mar 01, 2024

An electrical installation is an essential part of any room, office, or building. Every such installation requires maintenance, upgrading, or repair from time to time, which involves a certain amount of risk taken by the electrician (electrical installer) involved.

key safety rules and most common mistakes when making an electrical installation

Working with electrical installations always carries a degree of risk, however, it can be effectively minimized. The prerequisite is to follow safety rules, use the right tools and avoid basic mistakes that can lead to a failure or an accident.

Principles of safe electrical installation

Electricity in typical single-phase or three-phase installations can pose a serious danger to health and life. Therefore, for your own safety, you should wear appropriate personal protective equipment (goggles, gloves, clothing, footwear, insulating matting) and use safe tools and equipment (certified meters, testers, probes, insulated hand tools such as pliers, screwdrivers, combination pliers, open-ended or socket spanners). When working with an electrical installation in your home, you can increase safety by ensuring that the installation is properly designed and protected using the TN-S system, i.e. with a separate protective conductor for the entire system, which is only used to protect the connected appliances. Here, there are a few basic rules, the most important of which is to have a three-wire single-phase system (phase wire, neutral wire, and a protective wire) or a five-wire three-phase system (phase wires L1, L2, L3, a neutral wire, and a protective wire). The obvious conclusion is that in all rooms, sockets with a protective contact, to which a protective wire is connected, must be installed. The situation is similar with luminaires, which must be compliant with protection Class II: they also must be connected to a protective conductor.

Residual current circuit breakers and safe electrical cable routing

One of the key safety rules is to protect installation circuits with residual current circuit breakers and to use equipotential bonding that connects protective conductors with conductive parts of other installations in order to equalize the electric potential of conductive components. It is also necessary to route electrical cables in straight lines and always parallel or perpendicular to the edges of walls and ceilings: this is an absolutely fundamental principle and must be followed. Obviously, all cables should be concealed in special cable ducts, tubes, or trays, with the exception of multi-conductor cables covered with plasticized PVC sheath (the so-called polyvinyl), which can be freely laid directly on the surface or under the plaster. When installing sockets in bathrooms and other rooms where there is a risk of splashing or dusting of such sockets (garages, sanitary facilities, etc.), it is necessary to use appliances with at least an IP44 protection rating.

To ensure further safety at work with electrical installations in the building, it is advisable to run separate circuits for lighting, general-purpose plug sockets, plug sockets with a higher risk of splashing (bathroom, kitchen), and for some appliances that require individual protection (computers, server, etc.).

Making an electrical installation – the most common mistakes

Safety at work with electrical installations can be increased by avoiding some common mistakes:

Electrical installation at home – what circuits should it include?

Until as recently as 25 years ago, a typical electrical installation in detached houses consisted of 4 to 6 electrical circuits, including constant and recurring elements such as a lighting circuit, a socket circuit, and a circuit for devices with high power consumption, i.e. the so-called “kitchen & bathroom circuit”, which powered cookers, ovens, kettles or washing machines. Over time, another, fairly obvious circuit appeared among those designed to power the property, i.e. the circuit to which yard lighting, an electric gate, an intercom, or garden tools such as a lawnmower and sprinklers are connected. Today, the number of systems and devices (which are often very sensitive to changes in or loss of power supply) that require separate circuits is significantly higher. It can also be concluded, based on practical experience, that it is not worth overloading each circuit. It is, therefore, better to make more of them, taking into account possible future needs. Nowadays, the number of circuits that are worth considering when designing electrical installations for detached houses is often more than two or even three times as many as what was recommended 2 decades ago. Suggested optimized division of the installation into individual circuits is presented in the list below.

Backyard, surroundings of the property: backyard (garden) lighting, pool pump, electrically operated gate, driveway heating, pond, yard maintenance equipment all require a separate circuit or two, depending on your needs and the electrical load

choosing the right fuse for the circuit – how to match the fuse to the power?

Automatic overcurrent circuit breakers, commonly called fuses, protect individual circuits and the equipment connected to them. Their purpose is to immediately cut off the electrical energy in the event of a short-circuit or overload. This can happen immediately or with a delay, e.g. in the case of C-type fuses, which have a high inrush current capability. They are connected in the distribution box to the phase wire on one side and to a socket or a switch on the other end.

What are the characteristics of an automatic fuse?

Automatic fuses are quite a diverse group of products that can be divided according to several parameters. It is worth mentioning here the time-current characteristics, which specify the time after which the breaker will trip. In this case, proper choice of a fuse is extremely important, because a circuit to which sensitive electronic devices are connected must be protected in a different way than, for example, the one to which motors that require higher inrush current are connected. While discussing solutions for the protection of a home installation, we can skip some of the characteristics that are related to industrial applications and focus only on the first three of them.

How to choose the right overcurrent circuit breaker?

Choosing the right overcurrent circuit breaker for a specific circuit depends primarily on the type, or rather the degree of load in the circuit generated by the equipment connected to it. Here, calculations are necessary to correctly choose parameters such as: short-circuit breaking capacity, number of poles, tripping curve or rated current. In practice, for a circuit in a typical household installation, B-type DIN rail-mounted overcurrent circuit breakers should be used, with short-circuit capacity of 6kA and 10kA, as they are fully effective in protecting cables against overloads and short-circuits. For circuits operating under greater loads – such as kitchen or bathroom circuits – breakers with the rating of 16-20A are recommended. For standard “socket circuits”, 10A-16A fuses should be sufficient, and for a circuit connected to luminaires, a 10A fuse will be more than enough.

RCD – why is it important to install a residual current device?

Since quite recently, residual current devices – (RCD for short) – have become mandatory components installed in every household switchboard and in every new installation. They are often confused with overcurrent circuit breakers, but their operation and functions are completely different. In a nutshell, professionals distinguish three types of RCDs based on the differential current they can handle. These are, respectively:

How to install RCDs?

The method of installation of the RCD clearly reveals its mode of operation, as it is mounted in the distribution box in such a way that the phase and neutral conductors pass through it. When the situation is stable and safe, the current flowing in the circuit is the same as the current flowing in the neutral conductor. As soon as there is a fault in the installation, the current “leaks” and is present, for example, on the housing of an electrical appliance – as a result, the values of the phase and neutral currents start to differ. It is this difference between the two parameters that gave the name to RCDs, and its occurrence triggers a mechanism that disconnects the installation from the power supply.

The above description of the operation and use of RCDs largely answers the question posed in the title of the chapter. This equipment primarily protects users of the installation and connected devices against electric shock resulting from direct or indirect contact. This function may save not only health but also life. At the same time, RCDs minimize the risk of fire caused by a possible failure of the installation or appliances connected to one of the circuits.

Which accessories should be installed in a “fuse box”?

The distribution box, commonly known as the fuse box, is a built-in space in which all the circuits of the local electrical installation are grouped – both those routed inside the house and those leading outside, i.e. to the garden, yard, or driveway. This is where all the protections are located, thanks to which the installation functions properly and which protects the circuits, connected devices, and us – the users – in case of unusual and dangerous events or situations.

As a standard, every such box – often also called a switchboard or junction box – contains overcurrent circuit breakers, which protect the circuit and its users from the effects of a short-circuit or overload by interrupting the flow of current. Apart from them, the presence of at least one RCD is required. In the switchboard, you can also find a so-called isolating switch, which cuts off the power supply from the entire installation. This main emergency stop switch allows – for example in the event of a flood or fire – to immediately switch off the power in the entire facility.

In addition to the abovementioned basic components, there are often additional modules and accessories installed in the distribution box. Much depends on the age of the building and the electrical installation, and on whether the building manager has equipped the building with additional automation, which, along with the development of the ”Smart Home” concept, is becoming more and more popular in our households. The following list presents most of the possible additional modules and accessories available on the market that can be installed in a typical distribution box:

Three-phase installations: how do they differ from single-phase installations?

Three-phase installations are becoming an essential piece of equipment, not only in a home workshop or studio but also in any modern kitchen is detached or multi-residential houses. The three-phase power supply is a 230/400V installation, which consists of five conductors. Three of these are phase conductors and the other two are the neutral N and the protective PE conductor, which is rather uncommon in older three-\phase systems. Such an installation is used in houses equipped with devices and machines with considerable power consumption. These include electric cookers, hobs, electric boilers, instantaneous water heaters, boilers, washer-dryers, and underfloor heating systems.

Supplying power to high-power appliances is not the only benefit of a three-phase installation. Another one is safety and comfort: three separate phases allow you to use the abovementioned appliances at the same time without any worries.

Necessary components of a 3-phase installation (equipment, accessories).

Three-phase installations basically consist of the same components as single-phase installations. However, their individual circuits, which supply particularly important appliances with high power consumption (kitchen and workshop equipment), should be well planned. A recommended addition to such installations is three-phase sockets outside the house, in the workshop, or garage. They will supply power to construction equipment when needed, e.g. when the users decide to expand their house.

When it comes to protecting home electrical installations, it is worth making sure that tripping the residual current device will not turn off the power in too many places at the same time. Therefore, the optimal solution is to use at least 2-3 RCDs, including a separate one for three-phase devices. However, when choosing the right RCDs, it should be remembered that in this case, the key parameters are the cross-section of conductors and their load capacity. These parameters are particularly important for three-phase installations, hence the need to reach for B-type 20A circuit breakers.

An electrical installation is an essential part of any room, office, or building. Every such installation requires maintenance, upgrading, or repair from time to time, which involves a certain amount of risk taken by the electrician (electrical installer) involved.key safety rules and most common mistakes when making an electrical installationPrinciples of safe electrical installationsingle-phase or three-phasethree-wire single-phase systemfive-wire three-phase system (phase wires L1, L2, L3, a neutral wire, and a protective wire)Residual current circuit breakers and safe electrical cable routingcables covered with plasticized PVC sheath (the so-called polyvinyl)IP44electrical installationsMaking an electrical installation – the most common mistakesMistake 1: use of protections that are not appropriate to the loadMistake 2: choosing conductors with insufficient cross-sectionMistake 3: inconsistent use of colored conductorsMistake 4: discontinuity of insulation, incorrect insulation of contacts, or twisting of contacts within the electric switchboardMistake 5: missing or careless labeling of fuses and wires in the switchboard (fuse box)Mistake 6: excessive loads on individual electrical circuits and socketsElectrical installation at home – what circuits should it include?electrical installationLighting circuitLED lightingPlug sockets in roomsIT equipment – AV – TVPassageways (evacuation routes)Appliances with a power output greater than 1500WBackyard, surroundings of the propertychoosing the right fuse for the circuit – how to match the fuse to the power?fusesWhat are the characteristics of an automatic fuse?Automatic fusesType-A time-current characteristicsType-B time-current characteristics Type-C time-current characteristics How to choose the right overcurrent circuit breaker?Choosing the right overcurrent circuit breaker RCD – why is it important to install a residual current device?residual current devicesRCDHigh-sensitivity residual current devicesMedium-sensitivity residual current devicesLow-sensitivity residual current devices How to install RCDs?The method of installation of the RCDRCDs Which accessories should be installed in a “fuse box”?distribution boxswitchboard or junction boxSurge protectors often called surge arrestorsPriority relaysControl programmersElectricity meterIndicator lightsSocket outletsData transmission modulesrouters, converters (fiber optic internet), TV and Wi-Fi repeaters, switches, controllers, or power strips with 230V and USB socketsThree-phase installations: how do they differ from single-phase installations?Three-phase installationsNecessary components of a 3-phase installation (equipment, accessories).circuit