How to hang a chandelier - useful tips for connecting your own hands. We connect a chandelier with three wires to a double switch

Traditionally, it is believed that connecting a chandelier is a difficult task that a professional electrician should perform. But, there is nothing difficult in connecting two or four wires, so any man can easily hang a new chandelier in his house with his own hands.

Connecting a chandelier in a new home

If it's just built private house, and if it is self-built, then it all starts with wiring. Usually, it is made internal. Although, you can use external wiring, which is retracted into a decorative casing.

Internal wiring

In concrete, brick or wooden wall a special groove is made for electrical wires. This groove is called a groove. You can make it or special device, a wall chaser, or an ordinary chisel. In case of wooden wall- chisel. The same groove is made in the ceiling.

Creating a channel for wires

The wire is placed in a special casing, which is closed from above during interior decoration premises. Don't forget about junction box, from which the wires should diverge to the chandelier, to other lamps, to the socket and to the switch.

Junction box

The presence of a junction box will facilitate the replacement of the fragment electrical wiring if necessary.

External wiring

The principle of laying external wiring is the same, with the only difference that the strobe is not made, and the wire is fixed directly on the wall in an insulating decorative casing.

Wires in an insulating casing are hidden in the wall

If the switch is single-key, then two wires go from it to the chandelier. And if two-key - then four. Usually, pairs of wires in the chandelier itself different color so there are no connectivity issues.

Connection diagram of a single-gang switch

When conducting wiring, it must be borne in mind that to connect the chandelier, it is necessary to leave sufficiently long ends. This will make it easier to connect. Surplus can always be hidden either in a hole in the wall, or behind decorative cover chandeliers.

Chandelier mounting types

There are chandeliers that are quite heavy. And the safety of people under it depends on how well it is fixed. How it will be attached must be decided by looking at the fastening provided by the manufacturer. Usually, it is of two types:

• fastening with a strap;
• fastening with a hook.

How to hang a chandelier with a plank

Almost all modern chandeliers are attached with a strap. It is a strip of metal, which is fixed to the ceiling with self-tapping screws. To make the fastening secure, you need to drill two holes in the ceiling. Plastic chopsticks are hammered into the holes, to which the bar is attached with screws. Self-tapping screws, entering the chopiks, expand them, which makes such fastening even more reliable.

Photo: fixing a chandelier with a strap

After the bar is fixed on the ceiling, it is necessary to connect the wires to the chandelier. Here it is better to use the services of an assistant who will hold the product. Although, you can temporarily hang the chandelier at some distance from the ceiling with a strong and thin nylon rope. And after connecting the wires, hang it the way it should hang. In this case, one person can do all the work.

You should always use a ladder for this kind of work. No need to stack stools, tables, etc. This is dangerous for your health.

Wire connections may vary. On modern products, special couplings are sometimes made at the ends of the wires. Wires that come out of the ceiling are inserted into these sleeves and secured with a bolt. If there are no couplings, then the ends of the wiring and the wires of the chandelier are simply twisted together. They just twist. You can not connect the wires simply by making hooks at their ends, since the connection must be strong.

Photo: wire connections using a terminal block

Everything is insulated with high-quality insulating tape. If the wires are copper, consisting of many strands, then all the strands must be twisted together before connecting. Of course, the ends of the wires must first be cleaned of insulation.

On modern chandeliers at the ends of the wires there are special couplings for connection: just press the spring with a button or lever, insert the wire and that's it!

After the wires are fastened and insulated, you need to lift the chandelier and hang it on the bar. Usually, there is no problem with this. Each chandelier has a decorative casing with which you can close the ends of the wires. This work is facilitated when, during gating, in the place where the chandelier will hang, provide an additional recess.

How to hang a chandelier on a hook

If fastening to the bar is not provided, then a hole is drilled in the ceiling, a plastic chop is driven into it, and a hook is screwed into it. Usually the key is equipped with a special latch that is driven into drilled hole and then screwing expands the spacer. concrete ceiling drilled with a Pobedite drill to a depth of about 7-8 cm.

Content:

Purchase new chandelier is considered a very responsible and exciting event. After assembling it, many people have problems, especially if you have to connect a 5-light chandelier using various schemes. Not every apartment owner can cope with this task, if he does not have at least minimal knowledge in the field of electrical engineering. But, subject to certain rules, it is quite possible to connect such a chandelier on your own, or use it.

Connecting a five-light chandelier to a double switch

Connect chandelier to double switch possible in several ways. Most modern houses cable connection to lighting device carried out through the internal channels of the floor slabs. Normal connection will be possible if the connected cable has three cores. In some cases, a two-wire cable may be present, making it impossible to use a double switch.

Therefore, one should first consider classic version with 5-arm chandelier, 3-wire cable and double switch. First of all, you should check if the phase wire is connected to the switch. By specifications phase supply to the fixtures is carried out only through the switch, which makes their repair and maintenance safe.

AT modern designs chandeliers, all the wires are brought out and connected in separate bundles. Phase conductors are assembled in one bundle, and zero conductors in the other. In this case, the connection will be very simple. A bundle of neutral wires is connected to the neutral conductor of the cable, and the phase wires are divided into two groups, which are then connected to the corresponding keys. Each double switch is equipped with one common contact to which the phase is connected, and two terminals to which groups of light bulbs are connected. If there are two terminals in the upper and lower parts, then a jumper is installed on the input side of the phase wire.

If the wires of the lamp are not marked in advance in any way, you must first call them with the help and then group them. There is another recommendation that can significantly extend the service life conventional lamps incandescent. The fact is that the burnout of such lamps occurs precisely at the moment of switching on. The filament is in a cold state, so its resistance is low. During switching on, a surge of current occurs, which leads to the failure of the light bulb.

A similar situation can be avoided by a diode installed inside the switch on the first key. A voltage is applied through it, reduced by half. In this case, the thread is heated up gradually, the resistance increases and the voltage is applied in full by the second key. For such a circuit, diodes from any rectifier devices that fit inside the switch are suitable.

Connecting a 5-light chandelier to a triple switch

Increasing the life of conventional incandescent lamps will be more effective using a three-gang switch. In it, one of the poles is specially designed for the diode, which provides the initial inclusion in a gentle mode.

The principle of operation of this circuit is similar to the actions with a two-gang switch. However, here the possibilities are more extended. In addition to saving lamps, this mode allows you to select one lamp as a night light source. Using a chandelier as a night light can significantly save energy.

Thus, two- and three-gang switches used to control and connect a chandelier with five light bulbs make it possible to divide the lamps into several independent groups.

How to connect wires in a chandelier

Connection ceiling chandelier can be done in two main ways:

• through the switch (two, three-gang)

• via dimmer

And in one and in the other case, you get the most important thing from the lamp. Either the chandelier shines at maximum brightness using all the bulbs, or the lamp works with partial output, creating a pleasant illumination that does not hit the eyes.

Let's consider these methods step by step, starting from connecting the cable in the switchboard, and ending with connecting the wires in the chandelier itself. Special attention will be paid to the most common mistakes in the performance of these works.

How to connect a chandelier through a double switch

In order to make this connection, purchase the following materials:

First of all, take a three-core cable VVGnG-Ls 3 * 1.5mm2 and stretch it along the gate to the nearest junction box near the chandelier.

Leave a margin in it for cutting and connecting the ends.

In the electrical panel, remove the insulation from the cable and connect the phase conductor (let it conditionally be white color) to a single-pole machine.

Run the yellow-green and blue wires to the appropriate places (grounding and zero busbars).

It is advisable to mark the stripped cable in the junction box so as not to confuse anything in the future.

• L - phase

• N - zero

• PE - earth

Now, with another 3-core cable from the junction box under the ceiling, to mounting box below, where you will stand two-gang switch, you need to make an omission.

You immediately clean the veins and sign:

• L - power phase

• L1 - phase to the first group of lamps in the chandelier

• L2 - phase to the second group of lamps in the chandelier

You need to sign them both on the switch below and in the top box.

Peel off the insulation from both ends and mark:

• L1 - phase wire for connecting the first half of the chandelier

• L2 - phase wire for connecting the second half of the chandelier

• N - zero

• PE - earth

Now the most basic. It is necessary to correctly assemble all this and connect it together in the upper junction box.

In order not to confuse and not make mistakes, the inscriptions made earlier will come in handy. With them, all switching is much simpler.

Take the Wago terminals and simply join the cores with the same marking.

Then the box can be closed.

Connect the main power conductor L to the common terminal of the switch 1.

Usually it is separate, but not all manufacturers have such a design. Be careful!

L1 and L2 are connected to the lower terminals 3.4.

You mount protective and decorative strips and again rise up to the chandelier.

Here the question may arise, but how to find out which wires sticking out of the chandelier are phase and which are zero?

Especially if they are the same color. There can be 3,4,5 of them, depending on the type of lamp and the number of its horns.

This is where a multimeter comes in handy. You need to call the wires below, when the chandelier is not yet suspended from the ceiling.

Zero, according to the rules, should come to the threaded part of the cartridge and the light bulb (extreme contacts), and the phase to the central contact pin.

Switch the multimeter to the continuity or resistance measurement mode, and sequentially touch the wires and contact parts of the cartridges on each cover with the probes. You need to achieve a sound signal or find where the resistance is zero.

If there are several zero cores, twist them into one common one.

Go to direct connection. To facilitate the sequence, first connect the protective earth and the neutral conductor. To do this, use the connecting sleeves.

Although Vago terminals can also be used here.

After connecting the ground and zero, it remains to power two phases. Choose any of the cores and press the supply wires L1 and L2 with two phase wires on the lamp with sleeves.

All that remains is to fix the chandelier on the ceiling and check its performance.

How to connect a chandelier through a dimmer

Required material for installation:

• two-core cable VVGnG-Ls 2*1.5mm2

• three-core cable VVGnG-Ls 3*1.5mm2

• lamp

The initial stage for installing a 3-core power cable from the shield to the switch box is the same as in the previously considered option. The connection in the shield, again, is carried out to a single-pole machine.

The difference lies in the fact that not a three-core, but a two-core cable is now going down to the installation site of the dimmer. You need to mark it as follows:

• L - phase wire from the switchboard

• Chandelier - phase wire for connecting the chandelier itself

Put three inscriptions on its cores in the places of stripping the insulation:

• Chandelier (feeding phase)

• zero

• Earth

After that, in the box with the help of Vago clamps, you switch the cores according to all the inscriptions.

Connect the same marked cores to each other.

Go to the dimmer from below. The main power phase, which comes from the electrical panel (previously you signed it as L), is connected to the dimmer terminal labeled "L" or "phase".

Another core signed "Chandelier" is clamped under the screw with the dimmable load icon.

On the chandelier, connect the phase conductor signed “Chandelier” through a pressed sleeve to the supply wire of the lamp.

If you have several phase conductors coming out of the lamp (two, three, four carob chandeliers), then to connect the load through a dimmer, simply twist them into one common conductor.

It remains to connect zero and ground, apply voltage and check the operation of the entire structure.

Common connection errors

The main errors are related to connecting to a double switch. Three of them are the most common.

How does a normal chandelier connection scheme, for example, two or three arms, work? There is a phase that comes into the junction box.

In this case, zero comes only to the box and immediately goes to the chandelier, without going down to the switch.

This is where the first mistake lies. Many, unknowingly or having confused the markings, lower both the phase and zero down to the switch.

They lead to the terminals, after which they begin to turn on the key, and the machine knocks out from them.

Remember, zero should never enter the switch, but only phase. The zero core should immediately go to the ceiling.

The second error is again related to zero. Having mixed up the two wires, you can start zero through the switch, and not the phase.

It may even work for you, everything will work properly, but the voltage will be constantly present on the lamp. This is fraught with electric shock when you want to change light bulbs.

By turning off the key, you will break the zero core, and the phase will still go directly to the carob cartridges of the chandelier.

What else is dangerous such a connection? Through the filaments of the light bulb, the phase will come to the terminal clamps of the switch itself. If you remove the cover from it and start checking the glow on the contacts with an indicator screwdriver, you will be very surprised.

Even when the keys are off, the indicator will glow and show the presence of voltage, both on one and on the other terminal.

Moreover, if you make a similar measurement under the ceiling on a chandelier, then you will also find the presence of voltage on all three wires, except for the ground wire.

To make this effect disappear, it is enough to unscrew the bulbs themselves from the shades.

The third error occurs when connecting the phase supply wire on the switch, not to the main common contact, but to one of the outgoing ones. In this case, you will only have half of the chandelier glowing.

Since spring, I have been listening to the complaints of the household about the chandelier that hangs in the hall. They complained about the excessively frequent burnout of incandescent lamps, and in certain shades. They even marked these ceiling lamps with a marker. The chandelier had been in operation for five years already, everything was fine, and it was not clear that something could happen to it like that, for no reason at all. Therefore, the rapid failure of light bulbs was attributed to their Bad quality. But I was "beaten".

Chandelier repair

Having de-energized the electrical wiring in the apartment, he disconnected the wires of the chandelier from the terminal block and removed it from the ceiling hook. Disconnected shades immediately made it possible to see the unsightly state of the electric cartridges. The edges were warped and partially crumbled. This prompted to make complete disassembly lighting device.

Dismantling the room chandelier

These electric cartridges are made of plastic and are clearly not intended for the "hundredths" lamps that they liked to screw in there. The insulation of the wires closer to the points of their connection with the cartridge turned into a hard crust over the strands and cracked. The central contacts inside the cartridges, which were originally not High Quality, burnt and "choked" - lost any elasticity.

5 lamp sockets

The replacement cartridges, although they were not ceramic, looked much better than the previous ones. The outer diameter is 40 mm instead of 36 mm, which indicates an increase in wall thickness. Internal contacts made of metal are also of sufficient thickness and even with a special coating. In such a situation, if you are not a professional in repairing chandeliers, when choosing a replacement, no matter how funny it may seem, you need to go to the electrical goods store with the horn disconnected and with a ceiling from it, this is the easiest and reliable way so as not to "miss" with the pairing of new structural elements with old ones.

Plastic cartridge in the chandelier

To the new electric cartridges, new wires and everything is in bearing structures, which are assembled together by attaching to a common central element. Before connecting the wires inside the chandelier, I figured out the wires hanging from the ceiling and to which the chandelier should be connected, a screwdriver helped in this - an indicator after the mains voltage was applied. Black wire "0", gray phase #1, yellow-green "ground", blue phase #2.

Wire connections and adapter

Wiring diagram for a chandelier for 5 lamps

circuit diagram connecting a 5l chandelier to the wiring

Here is the wiring diagram itself, both in the chandelier itself and its connection to electrical network, it has no options, it can only be drawn in different ways, but depending on this, everything can be done correctly or not.

The second version of the scheme

The wires of phases No. 1 and No. 2 would be more correctly connected to the central contact of the cartridge, and the “zero” wires to the side contact. With the "ground" wire, not everything is so simple, that's why the question mark is drawn. If the chandelier is metal and has a “zero” wire installed by the manufacturer, then it is necessary to connect it to it, if not, then the connection is at the discretion of the owner. If the chandelier is made of dielectric (that is, not metal), then the connection with "0" is useless.

Installation of wiring chandeliers and lamps

First, the "horn" wires are connected, then those intended for connection to the terminal block are connected to them. The twists should be treated with an active flux, soldered with tin and insulated.

LED lamp 12 W and package

After replacing the cartridges, they decided not to screw incandescent lamps into them, neither high power nor small, but "broke" and purchased LED ones at 200 rubles apiece, a little expensive, of course, but the manufacturer promised a 24-month warranty + 25,000 hours of continuous burning + light output from each lamp 1200 Lm (lumens) + warm light. The passport power of each light bulb is indicated at 12 watts and additionally indicated that it is identical to 100 watts of incandescent.

Why do lamps often burn out?

Well, the reason for the frequent burnout of electric lamps before the repair, which really took place (now I admit), I think it is necessary to consider the combination of poor contacts of electric cartridges and high voltage (230 V is always available), and frequent switching on and off of the chandelier.

Before starting work on connecting a chandelier, I recommend that you familiarize yourself with its device.

Designation of chandelier wires

Contacts for connecting to electrical wires on the chandelier are indicated by the following Latin letters:

• L- phase,
• N- neutral wire
• RE- ground conductor yellow-green colors.

They began to apply marking on chandeliers quite recently, and in chandeliers that were released a long time ago, there may not be any markings. In this case, you will have to figure it out yourself.

About connecting a ground wire in a chandelier

In modern chandeliers with metal fittings, a ground wire is installed yellow-green colors. The ground wire is indicated in Latin letters RE. If the electrical wiring in the apartment is made with a ground wire (it must be yellow-green, but can be of any color), then it must also be connected to the terminal to which it is connected yellow-green chandelier wire.

In houses old building apartment wiring usually made without a ground conductor. In old chandeliers or those with plastic fittings, there is also no grounding conductor. In such cases, the ground conductor is not connected; it will not affect the performance of the chandelier, since it performs only a protective function.

In the photographs, the wires coming out of the ceiling and chandeliers are depicted in white, and this is not accidental. There is no single international standard for the color marking of wires in an electrical network, and even more so in chandeliers. Yes, and in Russia, the color marking of electrical wires has changed since January 1, 2011. Only the ground wire PE is marked yellow-green in the specifications of all countries. color.

Attention! Before connecting the chandelier, to avoid damage electric shock, it is necessary to de-energize the wiring. To do this, turn off the corresponding circuit breaker in switchboard and check the reliability of the disconnection using the phase indicator.

Chandelier connection diagrams

Despite all the variety of models, all chandeliers, including LED chandeliers with a remote control, are connected according to one of the schemes discussed below. To connect, it is enough to connect the wires coming out of the ceiling correctly to the terminals of the terminal installed on the chandelier body. The job is easy and anyone can do it home master even without experience in electrical engineering.

If 2 wires come out of the ceiling and chandelier

Connecting a single-horn chandelier, consisting of one light bulb, and a single-gang switch in electrical wiring is usually not difficult. It is enough to connect two wires coming out of the ceiling using any kind of terminal block with wires coming out of the base of the chandelier.

Although, according to the requirements of the PUE, the twisting of electrical wires is currently prohibited, but in a hopeless situation, given that the chandelier consumes low current, you can temporarily connect the chandelier by twisting, followed by insulation of the connection.

According to the requirements of the PUE, in order to increase operational safety, the phase wire in the electric cartridge must be connected to the central contact, and the switch must open the phase wire. It is advisable to follow this rule. But in practice, no one thinks about this, usually they connect the switch and the chandelier as they have to.

If 2 wires come out of the ceiling and multi-track chandelier

If the chandelier has several horns, but only two wires come out of it, then all the bulbs inside the chandelier are connected in parallel, and such a chandelier is connected according to the above diagram.

If 2 wires come out of the ceiling, 3 or more from the chandelier

Consider a more complex option for connecting a chandelier, the wires in it are connected to enable each light bulb to be turned on separately. For our case, all pairs of wires from cartridges, regardless of their number, must be connected in parallel. One of the options is to install an additional jumper from the wire (pictured color pink).

You can do without installing a jumper. It is enough to unscrew the screws at the first and third terminals, remove the wire coming from the left cartridge from the first terminal, and insert it into the third, along with the right wire coming from the right cartridge.

If 3 wires come out of the ceiling, and 2 wires come out of the chandelier

Usually three wires come out of the ceiling in case a two-gang switch is installed. First of all, you need to deal with the wires coming out of the ceiling - find a common wire. This is easy to do with a phase indicator.

To search for a common wire, you need to turn on both keys on the switch and sequentially touch each wire with an indicator probe. Depending on which wire opens the switch, phase or zero, two options for the indicator behavior are possible.

• When touching two wires, there is a glow, but not to the third. In this case, the wire on which there is no glow is common.
• When touching one of the wires, there is a glow, while the other two are not. Then the wire on which there is a glow is common.

Without a phase indicator, it is also easy to figure out the connection. You need to connect any two wires from the ceiling to the chandelier and turn on both switches. If the light turns on, it means that the connection has turned out with a common wire and one of those coming from the switch. You can leave everything like that. If there is a desire to understand the wires to the end, you need to connect by brute force so that when you turn on both keys on the switch, the light does not light up. Thus, it will turn out to find the wires coming from the switch.

It remains to clamp the common wire in the terminal and any other coming from the ceiling with a pair of chandelier wires. If necessary, connect the chandelier so that the light turns on with any of the two switch keys, then put a jumper (pink in the photo) or clamp the wires that are connected by a jumper in the photo in one terminal. The jumper can be installed not in the terminal block, but in the switch.

If 3 wires come out of the ceiling, several wires come out of the chandelier

If it is necessary that not all the bulbs of a multi-track chandelier turn on at the same time, but in groups, then the chandelier must be connected according to the above diagram. A prerequisite is the presence of a two-gang switch. You need to connect a two- or three-arm chandelier according to the method described above. It is determined from the three common wires coming out of the ceiling. One wire from the pairs coming from each chandelier cartridge is connected to it.

The remaining two wires are connected to the remaining free conductors from the pairs coming from the chandelier cartridges. It will be much easier to cope with connecting a multi-track chandelier if you familiarize yourself with its device.

Wiring diagram for 2-3 chandeliers
from a single switch

In room large area, or if a false ceiling is installed, for good lighting it is necessary to install several chandeliers or spotlights mounted in the ceiling, which must be turned on simultaneously with one single-gang switch.

Sometimes it is necessary to connect the switch in such a way that it can turn on the light at the same time in two, three or more rooms. In this case, chandeliers or lamps are connected in parallel, like several cartridges in one chandelier, according to the following scheme.

Each chandelier in the diagram is connected to the switch through a separate junction box, but all connections can be made in one junction box, it all depends on the wiring diagram in the room. If there are many horns in each chandelier, then they are connected in parallel, as for the connection case discussed above, when two wires come out of the ceiling, and three or more come out of the chandelier.

Wiring diagram for three chandeliers
from one three key switch

If in one or more rooms you need to turn on each chandelier separately from one three-gang switch, then you should connect the chandeliers according to the diagram below.

This option for connecting luminaires is often used when controlling luminaires installed in the bathroom, toilet and kitchen. One is installed in the corridor three-gang switch, and the corresponding chandelier is turned on before entering the room.

Chandelier connection
to the block of switches Viko (Viko) with a socket

Sometimes an additional outlet is required next to the switch. If necessary, it is advisable to change mounted switch on a block consisting of switches and a socket, for example Viko (Viko), shown in the photo. Switches for a chandelier in the block can be from one key to four. So there is an opportunity to choose the right one. In the photo - a two-gang block with LED backlight and one socket.

You need to connect the switch block with a socket to the chandelier according to the diagram below. As you can see, the circuit is not much different from connecting a chandelier to an ordinary switch, with the exception of an additional wire going from the neutral wire to the left outlet of the outlet.

In the diagram, the wire connection is shown in accordance with the requirements of the PUE; in real wiring, zero and phase can be connected vice versa. If, for example, there was a two-key switch, but you need a single-key switch with a socket, then you can not lay an additional wire, but use a free one by switching it in the junction box to zero or phase, depending on which wire comes to the switch.

Adding or extending wires
when connecting a chandelier

Now, during the renovation of the apartment, they began to install suspended ceilings. Stretch ones are especially popular. They have a great look, practically do not wear out, come in any color with glossy and matte surface are not afraid of water. Stretch ceiling are installed at a distance of 5-10 cm below the existing ceiling plane, so the length of the conductors to connect the fixtures becomes insufficient. It is required to increase their length.

The complexity of the task lies in the fact that it will be impossible to get to the place where the wires are spliced ​​to connect a chandelier or other fixtures after installing the ceiling without dismantling it. This means that the connection must be made in the most reliable way. Connecting wires in hard-to-reach places using a terminal block is not a reliable type of connection. The screws in the terminal block may loosen over time and need to be tightened.

In the article of the site “Connecting wires broken in the wall”, the methods of connecting aluminum and copper wires among themselves, just suitable for the case of extending wires for connecting a chandelier or other lamps. For a reliable connection when building aluminum wires with copper, I recommend reading the article "How to connect aluminum wires". To extend the wires to connect the chandelier to false ceiling one of the methods described in the article will do, on a thread or one-piece rivet.

Cross section of wire for connecting a chandelier

If six hundred-watt incandescent bulbs are installed in the chandelier, designed for a supply voltage of 220 V, then the current consumption will not exceed 3 A. This current can withstand a copper conductor with a cross section of 0.5 mm 2, and standard apartment wiring is usually made with wires with a cross section of at least 2.5 mm 2. So when connecting a chandelier with light bulbs for a voltage of 220 V, you don’t have to think about the cross section of the wire. When connecting a chandelier with LED lamps You don't have to worry about the cross section of the wire either.

When connecting a chandelier or fixtures with halogen bulbs for a voltage of 12 V, the current consumption becomes much larger, and the wire cross section in the wiring section from the step-down transformer or adapter to the chandelier lamps must be calculated using the online calculator below and checked for compliance.

The current consumption of which is ten times less than that of incandescent lamps.