Light switch

A light switch is often a hand -to-use, a mechanical switch on and off the lighting. He is a part of the electrical installation.

• 5.6.1 Battery-
• 5.6.2 Battery operated

History

Originally circuits were operated with open switches, which only had an insulated grip and thus did not offer enough protection against touching. With the invention of the light bulb by Edison and the advent of electrical installations there was a need for a safe switch.

First rotary switches have been developed which minimized the sparking mechanism with a spring and at shoulder height ( about 1.50 m) were mounted. With the standardization of the electrical installation, the present height of 1.05 m was proposed. The rotary switches were first replaced by toggle switches, as these are easier to use. Later even easier use rocker switch came on. Modern switch, with large rocker switches are referred to as surface. The latest development, switches, switch whose switching contacts when actuated and maintained this switch position, while the rocker returns to its previous state after the operation. An AC circuit or cross circuit is operated with such switches as a switch circuit.

During the development we came from the assembly earlier mainly applied onto the wall (surface ) and now widely used recessed mounted switch ( flush ), because this type of assembly reduces the risk of damage and the resulting potential exposure of live parts. On the other hand, increase recessed electric wires, the risk of electric shock when wall work (eg nailing or drilling). To minimize this risk, installation zones were defined. Refer to installation.

A special version is the damp-proof switch, which is available also for surface and flush mounting.

Material

Previously, light switches were made ​​of porcelain in the surface-mounted version and operated as a rotary switch with a rotary mechanism, then came those from Press fiberboard ( Bakelite ) because of the impact sensitivity of the porcelain on. Today they are made of modern plastics. Antimicrobial materials such as copper Chance, used to prevent infection, especially in hospitals and other public facilities, including light switch.

Installation

Electrical cables are installed for concealed installation in the so-called installation zones. Since these zones are standardized installation, it can be assumed that outside this range, no wires are laid. (Again, exceptions prove the rule, so be careful! ) Installation zones reduce the risk of accidents and damage during later alterations, renovations, etc.

When the installation is in accordance with the electrical codes ( see also VDE ) of the outer conductor to switch, so after turning off bears no voltage.

Switch for lighting systems are typically rated for a current of 10 A. In practice, lighting and socket circuits are, however, often combined with 16 A fuse. The fusing of the switch with 16 A for fixed lights is because it can be assumed that the current due 10 A will not exceed by the design of the lamp. In DIN VDE 0100-510:2012-06 it says this in the section 512.1.2: " When choosing a piece of equipment the intended operating current must be considered ( for alternating current, the rms value ), the result is there in undisturbed operation [ ... ] "

For the switching of outlets, there are two options: use of overcurrent protective devices with a rated current of In ≤ 10 A or use of installation switches with a rated current of 16 A ≥ In (mostly multi-pole switch).

Components

Light switch in the building installation are usually offered in three parts: use, frame and rocker. The insert is of the non-visible part that contains the technical function. The rocker name for the visible switch, which frame the outline, so the transition to the wall. Frames are offered one-to five-fold and group switches, dimmers, outlets of all kinds, controls and sensor into one unit.

Types

Switch

This component has at least two end positions in which the switch remains after pressing and so depending on the construction and position closes the circuit or interrupts. This type of control the lighting is mainly used in homes.

Off switch

The switch has one input and one output and two positions: "open" ( open circuit ) and " closed" (circuit closed).

Switch can be found, for example, directly on the luminaire or in connection pipe in the house installation in rooms with only a light switch. As a device for domestic installations pure switch are often not offered as changeover switch can also be used as a switch.

Change-over switch

The changeover switch has an input and two outputs, but it can also be operated with two inputs and one output. He alternates between output A and output B. That is, when the circuit is closed over A, it is interrupted via B.

According to DIN VDE 0100-460:2002-08 section 465.1.2 may not be used in the neutral single-pole switches. The misappropriation of change-over switches for the formerly often applied Hamburger circuit does not meet the current standards and is therefore prohibited.

Location: With two changeover switches a lamp from two locations can be operated. It must be taken at least two lines between the two switches. In the cross circuit also two AC switches are used at the ends ..

Series switch

A series switch called a double switch, so two independently operable switch with a common input and one output each for each of the individual switch. Outwardly can recognize this by a split rocker. It can be replaced by two switch.

The term series switch comes from the time in which the switch in the form of rotary switches were made with four switching positions.

Location: series circuit, such as lamps with two groups of lamps, two lighting groups

Intermediate switch

The intermediate switch has two inputs and two outputs, which are connected with two switching positions straight or crossed either, ie: either input A to output A and B with B or input A to output B and B connected with A. Intermediate switches can also be used as a removable switch or circuit breaker.

Location: In cross-connects the third and further switch between two -way switches, for example in bedrooms with light switches at the door and on each side of the bed. Cross-connects are now often replaced by impulse circuits with switches and latching relay, because the wiring is lower here.

Button

The button has only a basic position in which he falls back by spring force as soon as you let go. So he only sends a signal ( normally open) or interrupts the circuit (NC ) for a brief moment, he needs in the lighting control system still is an additional control, a bistable relay, which then the circuit will keep open or closed for the next control signal.

Location: pushbutton circuits are used in the stairwell lighting and wherever more than two places at the light to be operated.

Dimmer

Dimmers are light switches or touch - in addition to the switching on and off of the lighting and the setting of the brightness of the illumination by using a dial - or. Sensor dimmers - by touching a sensor area - allow. They are also often installed in table and floor lamps. They contain a phase control ( for incandescent lamps and transformers) or a phase control (trailing edge dimmer, eg for electronic transformers of low-voltage halogen systems)

Location: Wherever full or dimmed lighting is needed. Switch can be except for fluorescent lamps replaced by a suitable dimmer; in those an electronic ballast with dimming function is required.

Twilight switch

Twilight switch off automatically when an adjustable brightness value is exceeded or not. They are used as a light switch or roller shutter switch for shading. They have a hysteresis and best delay circuits, not continuously switched on and off, if the ambient brightness varies little

Motion Detector

Motion detectors replace today increasingly outside light switch. Turn the camera detects movement detection space, ie for example when a person approaches the outdoor lighting and automatically after an adjustable time again.

Radio switch

Battery-

Powered wireless light switch transmit the switching signal by radio to a receiver module that the lighting circuit on or off. The energy required for this is obtained from the switch operation: Pressing the switch a piezo element ( piezoelectricity ) is pressed, the mechanical converts into electromagnetic energy. Energy-saving electronics makes it possible to generate from this energy coded radio signals that hold about 30 m reach inside the building (outdoor up to 300 m). By encoding a unique association between the transmitting and receiving module is ensured.

Location: Without limiting. Especially suitable for office buildings, where the interior is changed often. Battery-free light switch can be mounted on walls or glass to wood, for example, because there is no cable feed is needed. Also suitable for use in older buildings where no cable ducts must be invested for this kind of switch, or - for the same reason - in wooden houses.

Battery operated

They work similar to the battery-free devices, but have as an energy source, usually a button cell. The battery life expectancy is up to 10 years. Then a change in the cell is required. Compared to battery-less devices, these often have the advantage of the larger variety of functions. Furthermore, the sensed pressure point in battery -powered switches softer, since only one electrical contact must be closed here. For this reason, the installation height of battery -powered switches is now identical with ordinary switches during batteryless switches still have a significantly higher construction.