Lighting for cabinets in the kitchen from LED strip: selection of elements, diagrams, DIY installation

Recommendation points

• The choice of LED strip
• Choice of power supply and additional devices
• LED backlight connection diagrams
• Tools and materials for mounting LED strips
• Choice of cable cross-section
• Installation of LED strip under kitchen cabinets

LED lighting under the cupboards in the kitchen is ergonomic, beautiful and modern. In the article we will talk about how to choose the right system elements, what connection schemes are, how to install the tape as an independent element and in a special box (profile).

The choice of LED strip for lighting under cabinets is an interesting, effective and not too difficult decision for a home craftsman. Such additional lighting, undoubtedly, also fulfills aesthetic tasks – it highlights separate functional zones, accentuates decorative elements with color, sets a fashionable, modern tone for kitchen design..

The choice of LED strip

An important characteristic of LED strip for installation under cabinets in the kitchen is its resistance to water vapor. Insufficient moisture protection can lead to a short circuit, and, therefore, to the risk of fire. When buying a tape, you need to pay attention to the degree of protection of the shell, which is marked with a two-digit number after the Latin letters IP. The first number indicates protection against dust and dirt, mechanical damage. The second number is moisture protection. The security of a device or device is assessed on a scale from 0 to 9 for both parameters.

For tightness (moisture and dust resistance), LED lamps and strips can be marked:

• IP33 – open type of conductor, not recommended for kitchens;
• IP65 – one-sided tightness of the side on which the electronic elements are located, it is allowed for installation in a humid environment of the kitchen space;
• IP67, IP68 – double-sided, complete tape tightness – recommended for installation in the kitchen.

If the selected lamp or LED strip has insufficient security, it is necessary to use a protective cover or special profiles in order to collectively ensure the proper level of security.

In order for the LED strip to give enough light, it is important to choose the right power density, which is characterized by the number of LEDs per linear meter. Each type of tape can have a different number of LEDs. This can be determined both visually and by looking at the characteristics of the product..

For decorative purposes, 30 or 60 LEDs per meter are usually sufficient. To fully illuminate the work surface, it is better to choose a tape with 120 or 240 diodes..

When calculating the illumination, you need to take into account the power consumed by the tape, remembering that, compared to incandescent lamps, the luminous flux of LEDs is about 5 times higher.

Table. Calculation of belt power

LED type	Number of diodes, pcs. / 1 ​​running. m	Power consumption, W / 1 running. m
SMD-3528	60	4.8
SMD-3528	120	9.6
SMD-3528	240	19.2
SMD-5050	thirty	7.2
SMD-5050	60	15
SMD-5050	120	25

The numbers in the tape marking indicate the size of one LED:

• SMD-3528 – diodes 3.5×2.8 mm;
• SMD-5050 – diodes of 5.0×5.0 mm.

For monochrome tapes with the specified characteristics, the luminous flux, measured in lumens and which is another characteristic of LEDs, will be maximum. For polychrome RGB strips, the color of which is set depending on the settings of the regulator or control controller, the total number of crystals in each diode corresponds to a combination of basic colors that do not turn on simultaneously. Consequently, when only part of the crystals that give a certain color are working, the luminous flux will be lower.

The colors of monochrome diodes with their own crystal glow are:

• red;
• Orange;
• yellow;
• green;
• blue;
• Violet.

The color of monochrome diodes is characterized by a narrow emission spectrum, which should be taken into account when choosing a backlight. The color of objects and, most importantly, products is significantly distorted, they may look different from under natural light or illuminated by fluorescent lamps.

The white monochrome LED is a semiconductor that emits ultraviolet light with a phosphor coating. The principle of operation is similar to the fluorescent lamps familiar to most. The hue can also be from “warm” to “cold” and is indicated in the form of the corresponding glow temperature, measured in Kelvin as in the usual LED lamps.

The color of the surface of the printed circuit board on which the LEDs are located is usually white, but other colors can be chosen: brown, yellow, black, which will look better on furniture when installed open. For ease of installation, the tape is equipped with an adhesive tape on the back..

Choice of power supply and additional devices

You cannot connect the LED strip to a household outlet – it will immediately burn out. It is designed to operate at a constant current with a voltage of 24 or 12 V, obtained through an appropriate pulse converter (power supply). The power of the device must correspond to the total power consumption of all connected tapes. For example, you need to connect three bobbins of 5 m SMD-5050, with a power of 7.2 W / r. m. The total capacity is:

5 m 7.2 W / linear m = 36 W

The power supply is chosen with a margin of 20%, therefore, you will need a device with a power of at least 45 W.

The block design can be different:

1. Sealed, compact unit in a plastic case.
2. Sealed power supply in an aluminum case. Expensive, climate resistant, often used in outdoor, street lighting.
3. Open unit in perforated housing. The most dimensional, inexpensive, requires additional protection from direct moisture penetration. There are powerful models – one block is enough for the entire backlight.
4. Power supply unit. Low power, up to 60 W, does not require installation. Multiple tapes will require separate power supplies.

The power supply for the kitchen must be moisture resistant or be installed in a place protected from moisture. It is desirable that the driver contain protection against voltage surges, which prolongs the life of the LEDs.

It is not recommended to connect LED strips in series, otherwise the wear will be high and the luminosity will be uneven. When connecting several tapes, it is correct to use an amplifier that provides uniform current supply to various sections of the electrical circuit.

If desired, the backlight can be connected via a dimmer – a device that smoothly reduces the power and luminosity of lighting devices. So you can maintain the backlight in the “work” and “rest” modes..

PWM controllers are used to control the LED strip, capable of providing the correct ripple current shape to adjust the brightness of the LEDs

Amplifiers and dimmers are matched to the backlight system by current strength.

LED backlight connection diagrams

Basic rules for connecting backlighting elements into the circuit and installation:

• respect the polarity;
• power it through a 12 or 24 V power supply in accordance with the type of tape and marking, placing it as close to the tape as possible (maximum distance – 10 m);
• the tape should not be sharply bent, twisted. It is better to cut and make the corner by soldering (with care, then insulating the conductive tracks with a heat shrink tube) or a special connector. Soldering, according to the experts, provides contact without electrical losses;
• the fewer connections and the thicker the wire cross-section, the less electric current losses;
• high power tape is best mounted in a profile (box);
• connect tape segments longer than 5 m only in parallel;
• place the power supply in a ventilated place to protect it from overheating.

The places where the LED strip can be cut are usually shown on the product itself..

Below are the basic connection diagrams for monochrome and RGB tapes.

Diagram of direct connection of LED strip. Several tapes are connected in parallel to one current source

Connecting the LED strip using a dimmer to adjust the brightness

Several LED strips, connected using a dimmer or PWM controller, must be connected using an amplifier

Connection diagram for RGB LED strips

RGB tapes are connected to the controller with four wires, three of which are responsible for one of the colors, the fourth is common. Marking: R – red (red), G – green (green), B – blue (blue). “V-plus” wire is common. The easiest way to connect is with a connector, but you can also gently solder. For autonomous connection of the controller and amplifier, sometimes two power supplies are used in the connection diagram.

Tools and materials for mounting LED strips

For self-installation of LED strip under kitchen cabinets, you will need:

• connection of elements can be done in various ways, and you will need: a soldering iron, solder, rosin and heat shrink tubing, or lugs for wires and crimping for lugs, or connectors;
• scissors;
• insulating tape, double-sided tape, fasteners;
• a tool for cutting holes in furniture for laying wires, for example, a jigsaw;
• selected LED strips;
• power supply unit and other elements of the electrical circuit, if necessary – dimmer, amplifiers, controller;
• box (profile) – when performing the appropriate installation;
• cable.

It is important to understand that LEDs still generate heat when they light up. It is directed to the substrate, the base of the diode. In order to prevent overheating of semiconductors, which significantly reduces their service life, it is advisable to glue the tape on a special aluminum profile or a substrate with high thermal conductivity..

Choice of cable cross-section

As a rule, a cable with a cross section of 0.5-2.5 mm is used to install the backlight in the kitchen.².

The cable cross-section can be accurately calculated using the formula:

Where,

• I – current strength, I = P / U or I = U / R (P – power, U – voltage, R – resistance);
• ? – resistivity, for copper cable? = 0.0175 Ohm mm²/ m;
• L – cable length;
• ?U is the maximum allowable voltage drop between the power supply unit (PSU) and the load (tapes),? U = U_BP–U?_tapes, if the voltage of the power supply unit is 12 V and the tapes are 12 V, then? U is taken at 5-10%, ie 0.6-1.2 V.

The cable cross-section also depends on the length of the wiring, the longer the wire, the less power will be supplied to the light source, which can be seen from the following table:

Length of wires, m	Load power, W
Wire section
1.5 mm2	2.5 mm2	4 mm2	6 mm2
0	50.0	50.0	50.0	50
2	45.5	47.2	48.2	48.8
4	41.5	44.6	46.5	47.7
6	38.1	42.3	44.9	46.5
8	35.0	40.1	43.4	45.5
ten	32.4	38.1	42.0	44.4

Installation of LED strip under kitchen cabinets

A well-executed installation is based on thoughtful planning – how to choose, where and which circuit elements to place.

The LED gives a directed beam of light, most often it is a 120 ° sector strictly along the central axis of the semiconductor. Less common options are 90 °, 60 ° and 30 °. By fixing the tape at the bottom of the hanging cabinet and stepping back from the wall, a very clear strip is formed on the vertical surface, moreover, wavy between light and shadow, which can adversely affect the overall picture.

It is necessary to distribute the light source so that the dividing strip of light and shadow from the backlight falls on a natural boundary, for example, between the edging of the work surface and the wall cladding. In the simplest case, the tape is mounted right next to the wall in order to illuminate it completely. By choosing different options, you can profitably work with the visual “depth” of the working surface for the overall design.

Strips with diodes, which have a narrow lighting sector, can be attached at the very edge under the cabinet so that the wall is not illuminated at all. A universal way to distribute light is to use aluminum profiles with light-diffusing protective films. Even the height of the profile sides, if desired, you can form the required shape of the illumination spot.

The installation itself, with some skill in working with the instrument, is not very difficult.

1. We pass the cable to the junction, as inconspicuously as possible, drilling a small diameter hole on the back of the cabinet.
2. The low power LED strip can be mounted directly to the prepared and grease-free surface of the lower part of kitchen cabinets. Measured length tapes with an adhesive layer are simply applied to the selected location and pressed, removing the protective film just before installation. If there is no such layer, you will need double-sided tape. To mask the tape, you can shield it with a profile to match the cabinet.
3. We fix the power supply, do the electrical wiring, carefully fixing the wires with clips or double-sided tape.
4. We connect all the elements in the circuit, be sure to check the wiring for a short circuit between the supply wires with a tester, and only then connect to the network. Backlight ready.

If, due to increased power or for aesthetic reasons, it is planned to install the tape in a profile, then first it is easier to lay the LED strip in the profile and connect the power leads. After that, using double-sided tape, the profile is fixed to the cabinets. You will have to change the sequence only if the profile is fastened with self-tapping screws screwed in from its inner side in a secret.

In the next video, the same wizard as in the previous video gives advice on installing tape in a box.