How do you Protect your Home's Electrical Installation?
An electrical installation is an essential part of any room, office, or building. Every such installation requires maintenance, upgrading, or repair every so often, which involves some risk taken by the electrician (domestic electrician) involved.
key safety rules and many common mistakes when making an electric installation
Working with electrical installations always has a degree of risk, however, it may be effectively minimized. The prerequisite is to follow rules of safety, use the right tools and avoid basic mistakes that may lead to a failure or an accident.
Principles of safe electrical installation
Electricity in typical single-phase or three-phase installations can cause a significant danger to health and wellness. Therefore, for your own safety, you should wear appropriate personal protective equipment (goggles, gloves, clothing, footwear, insulating matting) and employ safe tools and equipment (certified meters, testers, probes, insulated their hands for example pliers, screwdrivers, combination pliers, open-ended or socket spanners). Whenever using an electric installation in your house, you are able to increase safety by making certain the installation is properly designed and guarded using the TN-S system, i.e. having a separate protective conductor for the entire system, which is only accustomed to protect the connected appliances. Here, there are a few basic rules, the most crucial of which would be to have a three-wire single-phase system (phase wire, neutral wire, along with 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 the fact that in most 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 should be linked to a protective conductor.
Residual current circuit breakers and safe electrical cable routing
One from the key rules of safety 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 to be able to equalize the electrical potential of conductive components. It's also necessary to route electrical cables in straight lines and try to parallel or perpendicular towards the edges of walls and ceilings: it is really an absolutely fundamental principle and should be followed. Obviously, all cables ought to be concealed in special cable ducts, tubes, or trays, except for multi-conductor cables covered with plasticized PVC sheath (the so-called polyvinyl), which can be freely laid directly on the top or underneath the plaster. When installing sockets in bathrooms and other rooms where there is a risk of splashing or dusting of these sockets (garages, sanitary facilities, etc.), it is necessary to make use of appliances with a minimum of an IP44 protection rating.
To ensure further safety at the office with electrical installations within the building, you should run separate circuits for lighting, general-purpose plug sockets, plug sockets having a greater risk of splashing (bathroom, kitchen), as well as for some appliances that require individual protection (computers, server, etc.).
Making an electrical installation – the most typical mistakes
Safety at the office with electrical installations could be increased by avoiding some common mistakes:
- Mistake 1: utilization of protections that are not appropriate to the load – the effects include installation overload, which can lead to damage to appliances or result in a fire;
- Mistake 2: choosing conductors with insufficient cross-section – the effects are the same as when it comes to overloading cellular phone;
- Mistake 3: inconsistent utilization of colored conductors – the result, particularly in the case of three-phase appliances, may be the occurrence of voltage on the appliance casings, which may result in an electrical shock;
- Mistake 4: discontinuity of insulation, incorrect insulation of contacts, or twisting of contacts within the electric switchboard – this may lead to current leak (idle power consumption), short-circuits, and triggering of residual current circuit breakers;
- Mistake 5: missing or careless labeling of fuses and wires in the switchboard (fuse box) – such omissions allow it to be difficult to locate negligence the installation that should be temporarily disconnected;
- Mistake 6: excessive loads on individual electrical circuits and sockets – this common consequence of limiting the amount of circuits leads to the overload, which has recently been previously mentioned.
Electrical installation at home – what circuits should it include?
Until even as 25 years ago, a typical electrical installation in detached houses contained Four to six electrical circuits, including constant and recurring elements like 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 automatic washers. With time, another, fairly obvious circuit appeared the type of designed to power the home, i.e. the circuit to which yard lighting, an electrical gate, an intercom, or garden tools like a lawnmower and sprinklers are connected. Today, the amount of systems and devices (which are often very sensitive to changes in or lack of power supply) that need separate circuits is really a lot higher. It can also be concluded, according to working experience, that it's not worth overloading each circuit. It is, therefore, easier to make more of them, taking into account possible future needs. Nowadays, the amount of circuits that are worth considering when making electrical installations for detached houses is usually more than two or even three times as many as that which was recommended 2 decades ago. Suggested optimized division from the installation into individual circuits is presented in the list below.
- Lighting circuit: in the era of LED lighting, that is gradually replacing old-fashioned incandescent bulbs, it is safe and functional to produce a separate circuit for the kitchen, bathroom, exterior lights, in addition to a separate circuit for that rooms on each floor of the building.
- Plug sockets in rooms: sockets should be linked to another circuit or several circuits – depending on how most of them are now being connected and the size of your building. A separate circuit for every room is definitely an optimal solution.
- IT equipment – AV – TV: another electrical circuit for the computer, printer, scanner, stereo system, and residential cinema is highly recommended. For safety reasons, you should support such equipment with an uninterruptible power (UPS).
- Passageways (evacuation routes): all corridors, passageways connecting structures between the house and the garage, etc. ought to be connected to a separate circuit. This increases the safety of residents.
- Appliances having a power output greater than 1500W: all such appliances ought to be supplied by another circuit. Because there are now many appliances in our kitchens and bathrooms with a power consumption of a minimum of 2000W, experts recommend setting up several circuits – a person one for that induction hob, the dishwasher, the fridge, and also the kettle, the washer, the oven, your kitchen lighting, and also the extractor hood. As a rule, kitchen and bathroom sockets for small domestic appliances ought to always be connected to another circuit. Exactly the same applies to underfloor heating, that has recently become very popular in bathrooms (heating mats or cables).
Backyard, surroundings of the property: backyard (garden) lighting, pool pump, electrically operated gate, driveway heating, pond, yard maintenance equipment all need a separate circuit or two, based on your requirements and the electrical load
choosing the right fuse for that circuit – how you can match the fuse towards the power?
Automatic overcurrent circuit breakers, commonly called fuses, protect individual circuits and the equipment connected to them. Their intention is to immediately cut off the electrical power in case of a short-circuit or overload. This could 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 within the distribution box to the phase wire somewhere and to a socket or a switch on the other end.
What would be the characteristics of the automatic fuse?
Automatic fuses are quite an assorted number of products that could be divided according to several parameters. It's worth mentioning here the time-current characteristics, which specify time after which the breaker will trip. In this case, proper selection of a fuse is very important, just because a circuit that sensitive electronics are connected must be protected in different ways than, for example, the one that motors that require higher inrush current are connected. While discussing solutions for that protection of the home installation, we are able to skip some of the characteristics that are related to industrial applications and focus only on the first three of these.
- Type-A time-current characteristics – These are the most sensitive fuses and they will trip immediately when overload is detected. They are used to protect delicate electronics.
- Type-B time-current characteristics – These fuses are the most often found in homes and they protect, for example, lighting circuits or circuits connected to electrical sockets. Their overload trip current is 1.13 – 1.45 times greater, while the short-circuit trip current is 3 – 5 times greater than the rated current.
- Type-C time-current characteristics – Circuit breakers with this characteristic are used for the security of devices with an increase of inrush currents. They are able to protect circuits in a garage or perhaps a workshop. The overload trip current is the same as for that B-type fuses, as the short-circuit trip current is 5 – 10 times the rated current.
How to find the right overcurrent circuit breaker?
Choosing the right overcurrent circuit breaker for a specific circuit depends primarily on the type, or rather the quality of load in the circuit generated by the equipment linked to it. Here, calculations should correctly choose parameters such as: short-circuit breaking capacity, number of poles, tripping curve or rated current. In practice, for a circuit inside a typical household installation, B-type DIN rail-mounted overcurrent circuit breakers should be used, with short-circuit capacity of 6kA and 10kA, because they are fully good at protecting cables against overloads and short-circuits. For circuits operating under greater loads – for example kitchen or bathroom circuits – breakers with the rating of 16-20A are suggested. For standard \”socket circuits\”, 10A-16A fuses should be sufficient, as well as for a circuit linked to luminaires, a 10A fuse will be more than enough.
RCD – why is it important to use a residual current device?
Since quite recently, residual current devices – (RCD for brief) – have grown to be mandatory components installed in all households switchboard as well as in every new installation. They are often wrongly identified as overcurrent circuit breakers, but their operation and functions are completely different. In a nutshell, professionals distinguish three kinds of RCDs in line with the differential current they can handle. They are, respectively:
- High-sensitivity residual current devices(up to 30 mA), which are utilized in kitchens, bathrooms, workshops, studios, etc. – where the chance of fire the result of a faulty installation or appliance is very high;
- Medium-sensitivity residual current devices(from 30 to 500 mA), that are ideal for protecting general-purpose circuits in residential buildings or on construction sites;
- Low-sensitivity residual current devices(from 500 mA up), which are employed for circuits rich in leak current so that as main circuit breakers for the entire home electrical installation.
How to install RCDs?
The approach to installation of the RCD clearly reveals its mode of operation, as it is mounted within the distribution box in a way that the phase and neutral conductors go through it. When the situation is stable and safe, the current flowing within the circuit is the same as the present flowing within the neutral conductor. When there's a fault in the installation, the current \”leaks\” and is present, for instance, around the housing of the electrical appliance – consequently, the from the phase and neutral currents start to differ. It is this distinction between the two parameters that gave the name to RCDs, and it is occurrence triggers a mechanism that disconnects the installation in the power.
The above description from the operation and use of RCDs largely answers the issue posed in the title from the chapter. This equipment primarily protects users of the installation and connected devices against electric shock caused by direct or indirect contact. This function may save not just health but also life. Simultaneously, RCDs minimize the risk of fire caused by a possible failure of the installation or appliances linked to one of the circuits.
Which accessories should be set up in a \”fuse box\”?
The distribution box, commonly known as the fuse box, is a built-in space in which all of the circuits from the local electrical installation are categorized – both those routed inside the house and those leading outside, i.e. towards the garden, yard, or driveway. This is where all of the protections are located, thanks to that 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 it is users from the effects of a short-circuit or overload by interrupting the flow of current. Aside from them, the presence of a minumum of one RCD is needed. In the switchboard, there are also a so-called isolating switch, which cuts off the power supply from the entire installation. This main emergency stop switch allows – for instance in the event of a flood or fire – to immediately turn off the power in the entire facility.
In addition to the abovementioned basic components, you will find often additional modules and accessories set up in the distribution box. Much depends on age your building and also the electrical installation, and on if the building manager has equipped the building with a lot more automation, which, along with the growth and development of the \”Smart Home\” concept, is becoming more and more popular within our households. The list below presents most of the possible additional modules and accessories available on the market that may be set up in an average distribution box:
- Surge protectors often called surge arrestors: protect the electrical installation and also the equipment linked to it from damage that could occur because of the flow of high amperage current. This is a typical situation throughout a thunderstorm when lightning strikes a nearby transmission line.
- Priority relays: they monitor power distribution and load. When a lot of electrical appliances connected to the installation or circuit are switched on, these relays permit the appliances identified as a priority to operate. Other, less important ones are turned off.
- Control programmers: they're part of an easy home automation system and permit selected circuits to become powered at specific times based on a pre-set program. Typical applications include switching on lights before entering the house or starting the water heater.
- Electricity meter: this can be a compulsory element of any electrical installation and incredibly often it is set up in a fuse box, even though this is not the rule.
- Indicator lights, also known as indicators: are utilized to inform people that use the installation of the existence of voltage inside a given circuit or connection point.
- Socket outlets: they are most often associated with typical construction switchboards, however for some time now they are also set up in household distribution boxes, in single-phase and three-phase installations.
- Data transmission modules: these may be grouped together in separate multimedia switchboards, but could also function in a single common fuse box. They include devices such as routers, converters (fiber optic internet), TV and Wi-Fi repeaters, switches, controllers, or power strips with 230V and USB sockets.
Three-phase installations: how do they differ from single-phase installations?
Three-phase installations are becoming an essential device, not only in a home workshop or studio but also in almost any modern kitchen is detached or multi-residential houses. The three-phase power is really a 230/400V installation, featuring its five conductors. Three of those are phase conductors and also the other two would be the neutral N and the protective PE conductor, that is rather uncommon in older three-\\phase systems. Such an installation can be used in houses equipped with devices and machines with considerable power consumption. Included in this are electric cookers, hobs, electric boilers, instantaneous hot 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 make use of the abovementioned appliances simultaneously 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 significant appliances with high power consumption (kitchen and workshop equipment), ought to be well planned. A recommended addition to such installations is three-phase sockets out-of-doors, in the workshop, or garage. They'll supply capacity to construction equipment if needed, e.g. once the users decide to expand their property.
When you are looking at protecting home electrical installations, it's worth making sure that tripping the rest of the current device won't switch off the power in too many places simultaneously. Therefore, the perfect solution is to make use of at least 2-3 RCDs, including a separate one for three-phase devices. However, when choosing the right RCDs, it ought to be remembered that in this case, the important thing parameters are the cross-section of conductors and their load capacity. These parameters are particularly important for three-phase installations, hence the have to take B-type 20A circuit breakers.