Lighting scheme for 12V lamps: features of installing low-voltage networks

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You’ve probably heard about low voltage lighting networks, but the meaning of their use remained unclear. In this article, we will tell you why the use of direct current for household lighting makes sense, as well as in what cases and how you can convert the wiring in your own home..

Lighting scheme for 12V lamps. Features of installation of low-voltage networks

The use of low voltage to power lighting and other electrical appliances has been practiced for more than half a century. This trend originated in industrial plants where, for a variety of reasons, voltages of 36 volts and below were considered safe. When the contacts are opened, no sparks are formed in such a network, and the effect of such a low value on the human body does not entail serious consequences..

Today, with the development of more efficient light sources, the use of low-voltage networks in residential premises has become not only possible, but also very rational. It can be argued that laying a low-voltage lighting network in conjunction with the use of LED lighting sources is an integral part of modern renovation..

Low voltage advantages

As many know, such a dangerous voltage value as 220 volts is used in household networks due to the limited bandwidth of wires and the requirements for small-sized household appliances. For example, an electric kettle of the same power, but powered by a low voltage network, would load the wiring with about ten times the normal current..

Few people know that a significant part of modern household appliances have an operating voltage much lower than the mains voltage, they are powered through built-in transformers. Lighting networks can be attributed to this category of consumers. In the era of total rejection of incandescent lamps, it became possible to let a low voltage current through the lighting network, but why do this?

  1. Electrical safety. Such a small voltage is not capable of harming a person, most will not even feel this effect.
  2. Fire safety. Especially for lighting networks, where rather long sections of cable lines are laid in a flammable environment with open air access – in suspended ceilings. A short circuit in such a network is more likely to damage the transformer than burn the wiring..
  3. Reducing the number of transformation steps. It is known that it is cheaper to install one powerful transformer for the entire network than to supply each lighting fixture with it..
  4. Energy savings with low voltage light sources can range from 10% to 30%. Needless to say, low voltage lighting fixtures are more durable and don’t need to be changed as often..

Lighting scheme for 12V lamps. Features of installation of low-voltage networks

Problems and disadvantages of low-voltage networks

The most obvious disadvantage of low-voltage networks is the potential voltage loss during transmission of electricity through the conductor. In solving this issue, the density of the electric current plays a significant role. With a sufficiently large conductor cross-section, the losses are not so high.

As practice shows, the length of the cable line from the source to the consumer of low voltage is rarely more than 20 meters when it comes to household power grids. If these sections are laid with a standard 1.5 mm copper wire2, losses will not be tangible.

This may seem dubious for larger properties such as cottages and multi-story mansions, but they are wired in distributed circuits and taking into account the requirement of selective protection. This means that nothing prevents you from installing one transformer in each group panel..

Note! Here, not only the cross-section of the conductor is important, but also the quality of the material. Cheap Chinese cable products of the SHVVP or PVA brands are not suitable for these purposes. It is necessary to use cables of the VVP or VVG brands, in the veins of which there are no impurities of brass and silumin.

Optimal solution to the problem

As with any innovation, low-voltage lighting networks are best laid at the stage of building design. This will help to avoid problems such as cable overruns or improper junction box layout..

Lighting scheme for 12V lamps. Features of installation of low-voltage networks Assembly diagram of modular shields from distribution boxes

First of all, you need to take into account the additional space in the group shields for the installation of modular transformers. Devices like the ABB TS25 or HAGER ST313 occupy four modular spaces, while the more powerful HAGER ST315 occupies six modular spaces. The cost of such transformers is up to 3000 rubles, a rather high price is due to the possibility of mounting on a DIN rail. Free placement devices are cheaper, easier to find, and have a much higher power range. For example, devices such as TASCHIBRA can deliver up to 250 watts, which is enough to connect 30-40 halogen lamps.

If you plan on using LED light sources, conventional electronic transformers will not work for you. A stabilized current transformer is needed to power the LEDs. To get it, you can use devices like the Deluxe NV1236C LED driver (cost about 1000 rubles) or popular Chinese-made LED power supplies. If you need to mount the device in a group box, it is better to purchase an LED RGB controller, such as Supernova LED Dimmer for 2500 rubles. It has multiple PWM channels and can operate in standalone mode. This means that you can also configure it to control the brightness and color of the LED RGB strip..

Lighting scheme for 12V lamps. Features of installation of low-voltage networks House panel layout diagram

As for the connection and wiring diagram of such a lighting network, you most likely will not encounter difficulties. The transformer is connected to the mains voltage, further wiring is done independently of the system. Lighting is switched using conventional switches; polarity does not matter for halogen lamps. But in the case of LED lamps, especially those operating in RGB mode, you will have to maintain the polarity and put only the positive wire in the gap..

You can also experiment and run the four-way control circuit through the three-rocker switch, opening the minus contacts of different colors. Such a switch must have three independent keys, so use Schneider Electric WDE 000331 or its equivalent. In this case, it becomes possible to control the shade of the glow without preliminary adjustment of the controller.

Lighting scheme for 12V lamps. Features of installation of low-voltage networks Examples of wiring junction boxes

Low voltage lighting in a residential apartment

The question involuntarily arises: is it possible to install a low-voltage lighting network in an already inhabited apartment? Yes, you can. Maybe not so economically and with the loss of a number of opportunities, but it is possible. It is most advisable to carry out such modernization during the overhaul of electrical wiring (this way you will avoid the need to install junction boxes). It is advisable to lay the power cables of the outlet lines along the floor, connecting the sockets in a chain.

For laying the cables of the lighting line, you can use the cavities of the false ceilings, thus almost completely eliminating the need for horizontal gating. But there is also an alternative layout of the circuit: if you replace the junction boxes with modular shields, you will not only ensure selectivity of overload protection, but also get a place for installing transformers.

Little Tricks for Low Voltage Lighting

And a little life hack as a conclusion. How often have you encountered the need for standby night lighting so that you can walk through a dimly lit room at night? If you have low voltage wiring, there are two interesting solutions to this problem..

The first is quite simple: put in each box with a switch a small piece of LED strip or a bunch of NE-2 neon bulbs connected through a current-limiting resistor from 100 kOhm to 5 megohm.

This will give you a pretty interesting inner glow effect. Light will ooze from all the cracks and gaps between the plastic parts, which looks rather unusual and gives the necessary level of illumination for orientation in complete darkness.

The second option: the backlight can be made brighter by mounting super-bright LEDs directly into the frame, but this is a rather difficult job. First of all, you need to make a 1 mm groove in the lower edge of the frame, removing some plastic at the end with sandpaper. LEDs must be soldered in series, the optimal number of which is three pieces. A current-limiting resistor is also sequentially soldered into the circuit, the value of which is selected individually.

The entire garland is fixed in the cavity of the switch frame with a glue gun or silicone sealant; it is advisable to orient the LED heads to the edge of the frame. And if you make several thin strobes during the repair and put a thin two-core wire into them, you can also highlight the sockets.

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