- Questions first
- One RCD for the whole apartment or a separate RCD for each dangerous room?
- Is it possible to lay an additional wire?
- Choosing a place to install an apartment board
- Which shield to choose
- How many groups to split the network into?
- Which RCD to choose
- How can you install a shield for an RCD in a three-room apartment of an old panel house
For example, you decided to make a renovation without redeveloping an apartment. Here is the right time to protect yourself and your loved ones from electric shock. This can be best achieved by extending an additional wire into the apartment for grounding electrical appliances and installing an RCD.
During the repair, it becomes possible to open the places in the walls where the wires are connected. You can check the channels for wiring additional wires, if necessary, clean them, gouge these channels. Select an apartment panel for installing the RCD, the place of its installation. At the same time, it is considered into how many groups it is better to break up the apartment power grid, how many and which RCDs to install.
The article discusses these issues and features of work on the installation of an RCD. An example of reworking the power supply to a three-room apartment of the old layout of a panel house is given.
Only electricians should carry out electrical work..
The need to install a residual current device (RCD) usually arises among residents of apartments of an old building. There is no grounding conductor in the bathrooms, in the rooms. And in the kitchen, the grounding of the electric stove does not provide voltage shutdown in case of damage to the insulation of the neutral conductor.
If a decision is made to provide protection and install an RCD, it is necessary to answer two important questions:
- It is necessary to provide protection throughout the apartment, or only in the bathroom and in the kitchen?
- Is it possible to lay an additional ground wire to the connection points of electrical appliances?
One RCD for the whole apartment or a separate RCD for each dangerous room?
In the case of installing one RCD for the entire apartment, a situation will inevitably arise when, after damage to the insulation of the wire in one of the rooms (for example, in the bathroom), the entire apartment will remain without voltage. Until the malfunction is eliminated, the entire apartment will remain without electricity. Detecting insulation damage takes time and skill.
For the convenience of operating the electrical network, it is better to install an RCD separately for each hazardous room.
If, nevertheless, it is decided to install one RCD for the entire apartment, you should install sockets for connecting each electrical appliance in the toilet and in the bathroom, in other places where leakage is most likely. What to do in case of protection tripping? Unplug all electrical appliances from electrical outlets. Then turn on the RCD, connect the water heater, washing machine, and other devices in turn. Turning on the device with damaged insulation will trigger the protection. It is necessary to make an audit of this equipment.
Often the problem of insulation failure arises in the water heater. The RCD starts to turn off rarely at first, then more and more often. The weak points here are the protective cover of the thermostat and the shell of the heating element. If the thermostat cover starts to leak, water appears in the temperature control unit.
It is not always possible to detect damage visually. It is better to check the insulation resistance of live parts with a megometer. It is also possible to turn off the RCD if water leaks onto live parts due to poor sealing at the junction of the heating element with the water heater tank. In this case, it will be enough to clean and dry the live parts of the heater, restore the seal.
Is it possible to lay an additional wire?
Here it is enough to answer the questions about where the wires are laid in the apartment, where are the places of their connection, what is the state of the cable channels in the walls and ceilings.
All work is performed only after disconnecting the voltage in the apartment electrical network.
In floor slabs, in walls, if it is a panel house, wires are laid in channels. These channels are already made during the production of reinforced concrete products. If the channels are damaged or completely destroyed during the transportation and installation of products, the wires can simply be walled up in a plate or panel. In such places, the position of the wires can be determined by light tapping. The sound when tapping an undisturbed surface and cement mortar is different.
The wires from the socket to the socket and to the switches are laid at the junction of the walls with the floor slabs. Most often, these channels are bricked up with a complex or cement mortar. The direction of laying the wires in the floor slabs is determined at the connection points of the ceiling lamps.
In brick houses, the wiring is usually laid in grooves and walled up. As a rule, a complex mortar was used to seal the cable ducts. It is not very difficult to clean the grooves in this case..
The connection points of the wires are easy to determine. Run a vertical line from installed outlets and switches to the ceiling. At the meeting point of the vertical with the floor slab, there will be a connection point for the wires, although not always. For such surveys, it is best to use a plumb line..
To determine the passability of the cable channel, try to pull through it a springy wire with a diameter of 1–1.5 mm. The ends of the wire must be bent and wrapped with electrical tape so as not to damage the insulation of the already laid wires, so that there is no snag when pulling out. If it is impossible to drag the wire through, the channel is clogged with concrete sludge, mortar, debris or destroyed. In order to pass the wire, the channel must be pierced.
Pulling the wire into the channels is also carried out using a wire. Therefore, before starting work, you must stock up on wire. A section of approximately 20 m is enough for you to carry out all the work.
At the end of the survey, you can approximately calculate the number of circuit breakers, RCDs and wires that are necessary for installation in an apartment.
Choosing a place to install an apartment board
The entry point for the wiring harness from the switchboard on the staircase is on the same wall where the entrance door is located. Usually the point from which the wires begin to diverge through the rooms is located near the place where the harness is inserted, under the ceiling. Close to this point it will be rational to install an apartment board.
When choosing a place to install the switchboard, take into account the conditions for safe operation of electrical equipment and ease of maintenance. Aesthetic preferences of residents play an important role in choosing a place..
Here are some basic requirements for the installation site of the apartment board. The apartment board must not interfere with the movement of people. You can not install the shield in a place where it can be littered with things. The approach to the shield should be free and comfortable. The possibility of children entering the shield must be excluded.
In three-room apartments with an old layout in panel houses, a storage room can be a good place to install a shield. There is enough space here, and the pantry is separated from the hallway by a wall..
Which shield to choose
The choice of the switchboard depends primarily on what electrical products will be installed in it, how many of these devices are, in which room it will be installed.
Electricity meters are usually installed in boards on the staircase, so it makes no sense to buy a board with a mounting place for such a device. Such a shield has large overall dimensions, it will require more space for installation.
Circuit breakers and RCDs are mounted on a DIN rail. Consequently, a rail must be present in the shield, allowing the required number of products to be placed on it. Please note that the RCD has two poles, that is, it takes up as much space as two single-pole circuit breakers. When buying, ask how many single-pole circuit breakers can be installed in a switchboard. In addition, in the future it may become necessary to select an additional group from the lighting network. Therefore, it is better to have a spare space in the switchboard for installing two or three circuit breakers..
In addition to the DIN rail, the apartment board must be equipped with two buses. One bus (PE) is used to connect the ground wires. Another bus (N) is used to connect the neutral wire coming from the RCD. To ensure the possibility of connecting aluminum and copper wires, the busbars are made of steel. The zero bus is installed on an insulating base or gasket.
In our case, it makes no sense to install a built-in shield. To install it, you will need to gouge a niche in the wall. Therefore, it is best to choose a hanging shield.
The degree of protection against dust and moisture for an apartment panel is not particularly important. The degree of protection IP 31 will be sufficient. It is obligatory to have a false panel and a door with a lock in the shield.
The choice of the material from which the shield is made, design – completely depends on the preferences of the residents. And yet it must be borne in mind that a shield installed in a utility room (for example, in a pantry) can touch when carrying household equipment and things. Steel body is still much stronger than polymer.
Next, you need to determine how the wires will be inserted into the shield. For the apartment switchboard, it is not very important to have gland seals for cable entry, even in the case of cable entry in a cable duct. If the shield has an open back, it will be enough to gouge a small recess in the wall. The wires will go up to the shield in the cable channel, then enter the shield through a recess in the wall.
As one of the options of choice, the switchboard SHRN3 1-9-UHL4 produced by TM “Uzola”.
How many groups to split the network into?
Three circuit breakers were installed in the boards on the landing of old panel houses for each apartment. Consequently, the entire apartment electricity network was divided into three groups.
You can immediately allocate one RCD in the apartment board into two groups. But with the line to the outlet for the stove, the situation is somewhat different. The wires for this outlet do not go into the hallway. They are held in the wall from the side of the landing..
The exit can be found as follows. Disconnect the wires going to the kitchen socket in the switchboard on the landing. Then remove these wires from the tray on the site before entering the apartment, pull them through the input into the apartment to the junction. Lay a new 3-core wire or cable from the general panel to the apartment to the panel. In this case, you can already get closer to solving the problem with the presence of a ground wire in the apartment. Next, you need to stretch the ground wire from the apartment board to the connection points of the devices.
It will be necessary to lead a three-core copper wire to the bathroom to connect the sockets for the water heater, washing machine and lamps. A separate machine is installed on this line.
Now you can make the final decision on how many groups the apartment network will be divided into, how many circuit breakers and RCDs will be needed, which shield to choose, where to install it. The scope of work can also be calculated.
Which RCD to choose
The main characteristics of the RCD, which should be taken into account when choosing, are as follows: number of poles, setting of leakage current, rated current.
For use in an apartment, you must select a 2-pole RCD. Leakage current setting is allowed no more than 30 mA. The choice according to the rated current depends on how many protection devices are installed in the apartment. Here you can choose from a range of 6-63 A.
Choose an electromechanical type A RCD for installation. It will provide protection not only from sinusoidal alternating current, but also from pulsating direct current..
When purchasing, look at the certificates of conformity and fire safety of the products. There are a lot of fakes on sale that do not provide protection.
How can you install a shield for an RCD in a three-room apartment of an old panel house
Tray 1–2–3–4 ran a 3-core wire to an outlet in the kitchen. The wires are disconnected in the staircase. In tray 1–2, the wire was removed from the wall and brought into the apartment at point 2. The rest of the wires that were brought into the apartment during construction were removed and removed from the common board to the connection point 7 in the apartment. After completing these works, there is not a single wire from the general panel to the apartment panel.
Point 7 is where the wires are connected. From here comes the wiring throughout the apartment. At point 6, a hole was drilled in the wall between the hallway and the storeroom. A 4-core cable (one spare core) was brought from the staircase through channel 1–2–5–6–8–9 through the hole at point 6 to the apartment panel in the storeroom. Tray 7-6-5-2-3-4 now runs a wire to an outlet in the kitchen. On section 6-7, wires are laid from the apartment board to the common point of the wire divider.
A cable duct is installed between points 8 and 9. In the cable channel at section 8–9, a cable has been laid from the general board, wires from the apartment board in the direction of 9–8–6–7 to the connection point common for the whole apartment. The wires from the cable duct are led into the shield from the back through a recess cut in the wall. The shield has a false panel and a secure door. Steel shield.
After discussing all the features of the RCD installation, the following conclusion can be drawn. This whole event should be considered as a set of works. Before starting the installation, you will have to make an examination in the apartment, make preparatory work. It is best to entrust a qualified electrician to make a choice of RCDs and circuit breakers, wires. If you have prepared and professionally installed electrical equipment, you and your loved ones are guaranteed reliable protection against electric shock in your old but beloved home..