- Installing the shield body
- Cutting and laying of cable products
- How modular devices are assembled
- Conductors and electrical connections
Installation and disconnection of modular equipment is the final stage of wiring. We will tell you how to properly assemble and install the switchboard, and what stages its filling is divided into. You will also learn about the correct implementation of electrical connections and putting the power grid into operation..
Installing the shield body
First, let’s make a reservation that there are two assembly methods: bench and hinged. And each of them has differences in the installation of the case. The essence is very simple: the filling of the shield can be installed and disconnected after it is thoroughly fastened, or vice versa – the shield is fixed with all the filling and all that is required from the installer is to connect the outgoing lines according to the diagram.
By type of installation, distribution boards are divided into recessed and surface mounting. Most outdoor enclosures can still be tucked away in a niche, but flush-mounted products cannot. It is believed that recessed shields are preferable due to their compactness, besides, the installation is more technological and the internal environment is better localized. And this is so, but with a number of exceptions: open-type wiring, mounting on a load-bearing wall, the inability to make a niche for other reasons.
In some cases, the installation of a hinged housing with its partial embedding into the wall can be very important. For example, with a mixed type of wiring, it is convenient to bring conductors to a half-recessed shield both from cable channels and embedded in the wall. Where a recessed installation is really not recommended is on highly combustible substrates (outdoor installation on an insulating panel only) and in framed buildings with false walls. In the latter case, special shields are used for installation in hollow structures, but with high intensity of use, it is better to give preference to the overhead type of housing.
Cutting and laying of cable products
It will not be an exaggeration to say that cutting cable outlets on the shield is the most crucial stage of installation. Damage to the insulation is unacceptable here, so it is recommended to purchase a knife for removing the belt insulation, even if not of the best quality and only for one-time use.
Similar requirements are imposed on the removal of core insulation: it cannot be cut off with a mounting knife or any other knife, squeezed with pliers and melted. To remove insulation, there is a special tool – a stripper, he is also a skinner. Its price is also not so high as to openly sacrifice the quality of work. It is critical that the metal strands remain intact, no exaggeration.
The rest of the technique is simple: the belt insulation is removed almost completely, but it is always present at the place where the cable passes through the housing, plus another 5–6 cm. The conductors cleaned by 12–16 mm are passed under the mounting rails and are conducted according to their purpose: zero and protective conductor to the common blocks, and the phase load to the corresponding safety group. It is highly recommended to leave a good margin of length, to guarantee – pull the core to the opposite corner of the shield and cut it there with a margin of palm width. The excess can then be cut or rolled into a spiral and left so in case of rearrangement of equipment inside.
How modular devices are assembled
There are no categorical standards recommending the placement of modular equipment by type in a certain sequence. And yet, it is better to adhere to some natural rules so that the structure of the circuit is understandable to other masters, and the purpose of the controls is mnemonically accessible to the user..
It would be quite logical to place an introductory machine at the beginning of the upper row, next to it is also a block of general-purpose protective and measuring devices. Firstly, they are rarely used, which means that the most frequently used elements will be located lower, in a more accessible place. Secondly, it is more convenient to conduct internal wiring this way. Just remember for now that the input unit is connected to the upper terminals, and the voltage is removed from the lower.
Following in order from top to bottom and from left to right, group type RCDs are installed next. At least one protects general-purpose outlet groups, and one each for the kitchen and bathroom. If all outgoing lines are protected by current, installation of difavtomats instead of RCDs is not required.
Regarding automatic switches: the protection of the lighting lines is installed first, then the general socket groups, then special consumers and dedicated lines: a tank, a washing machine, an electric boiler. There is also an alternative principle of placement, in which, first of all, protection groups for high-power and three-phase consumers are placed, but this approach is useful only when building industrial and general house networks with currents at the input of more than 100 A. This arrangement allows you to connect several input circuit breakers without physically breaking the core lead-in cable.
Conductors and electrical connections
The technique has been installed, it remains only to separate the conductors, without forming a bulky web. First, let us establish that only one core can be connected to one terminal clamp. If you need several – take the trouble to squeeze them with a sleeve tip and cover the bare ends with heat shrink. Before fixing in the clamp, the core must be rolled into a small loop.
The second point: for modular devices, as a rule, it does not matter from which side you supply voltage, and from which side you take it. The rule for connecting to the top terminals is only applicable for panel mounting technology with a removable casing, so that the drive mechanism can be serviced when disconnected..
If you mount it by weight, first of all, lay out the outgoing lines, pass the wires under the DIN rail and pull to the connection point. It is convenient to hide the folded excess cable in a “pocket” between the machines and the back wall. All cores are packed in loops according to their intended use using nylon ties. A bundle of neutral wires is connected separately, grounding is separate, each of these two groups has its own route of laying. It is better to pack the phase wires in rows, that is, bring the loop vertically to the rail, and then dissolve it on the sides. So there will be room in the technological gap for laying the connecting jumpers..
It is convenient to use an insulated connecting comb to connect one row of machines. They are one- and three-row, if any machine in a row needs to be powered from another source, just bite off the contact pad. One important feature distinguishes the combs – the way they are connected to modular technology. The comb can have long rectangular pads for standard terminal clamps, but in some cases the legs are specially shaped for the corresponding socket in the modular component. As an example, we can name the products of large manufacturers of electrical products, where bifurcated pads are used for landing under a tightening screw, that is, at the same time, one clamp can tighten both the cable core and the comb pad. Otherwise, it was necessary to “throw over” the power supply, installing an introductory machine in each row.
When assembling the shields, all kinds of consumables can be of great help. So, to group the protected RCD lines, their zero conductors must be assembled on a separate block, which has from 6 to 18 holes with screws and a plastic case for installation on a rail. It is recommended to place the pads on the edge of the row so that they are covered by the front panel.
Travel stops with screw or spring locks will help to fix the automatic machines against shear. If consumer wiring is made inside the panel, which is often practiced in group assemblies, spring terminal blocks are used for connection, for example, WAGO.
Major panel builders supply panels with an extensive list of useful consumables. Here, there are cable clamps, and gland seals, plugs for the front panel and even special frames with guides that allow you to “roll out” the frame with attachments for more convenient assembly.