Electrical networks of apartments are extremely rarely divided into power and lighting boards. Typically, such equipment is housed in a single enclosure. A similar situation occurs in office and small industrial premises.
Network separation
Despite this, in some situations, separation of power and lighting networks is required for several reasons:
- The need to create emergency power.
- Installation of lighting control devices.
- Indoor conditions.
- Location of cable routes.
- Convenience of operation.
In these situations, only shields are installed for the functioning of lighting devices and they are marked with the acronym SCH.
Lighting design
The same requirements apply to lighting boards as to distribution boards. The power supply is carried out through a switch or an automatic input switch, designed for the load created by all devices connected to the switchboard. When using the switch, the power line of the shield is necessarily protected by a circuit breaker, the protection zone of which should cover the wiring stretched to the automatic machines of the outgoing lines.
Outgoing lines are equipped with their own circuit breakers, the rated current of which is calculated based on the total connected load. It is permissible to connect several outgoing cables to one circuit breaker, however, when repairing wiring or lighting, it is necessary to disconnect all powered devices, and therefore it is not worth saving on the number of machines.
Lighting wiring, designed in lighting, is three-wire. The luminaires are powered by a working zero conductor and a phase conductor. The working zero core in the cable is made in blue. Housings of lighting fixtures are grounded by a yellow-green conductor, which is part of a three-core protective cable. It is forbidden to connect the neutral conductor and the lamp housing.
There are two busbars in the lighting board for connecting neutral conductors: N for working conductors and PE for protective conductors. Grounding the reflector is not required if the housing of the lighting device is made of non-conductive material, and the reflector is made of metal. However, the cable is in any case used three-wire, as in the arrangement of outlets without grounding contact.
Portable Power Boards
Portable luminaires located in rooms with a high level of danger are powered by a voltage of not more than 50 V. For this purpose, step-down transformers that convert voltage are installed.
Especially for such transformers, special guards of a special design are made with the following components:
- A step-down transformer that converts voltage to the desired voltage.
- Circuit breaker designed to protect the winding from high voltage.
- Circuit breaker for protecting lines on the low voltage side, extending from the transformer.
- Socket for connecting portable devices.
Not only sockets are connected to the transformer, but also cable lines leading to stationary lighting fixtures. Luminaires powered by low voltage are most often installed in rooms with a high risk of electric shock.
Luminaires operating from networks with a voltage of not more than 12 V are installed in the following cases:
- Small-sized premises.
- Inconvenient position for work.
- Permanent contact of an employee with grounded metal structures.
A step-down transformer can be installed in lighting panels used to connect general lighting.
Outdoor lighting panels
Unlike a conventional lighting board, the outdoor is equipped with an automatic or manual warning device. To control outdoor lighting in automatic mode, use:
- Photo relay. Reacts to the level of lighting in the territory under its jurisdiction.
- Sound sensors.
- Motion sensors. They fix the appearance of people or animals in the illuminated area.
- Annual or monthly relays, programmable to turn on the light at a specific time, changing throughout the month or year.
- Relay, including lighting, depending on the geographical coordinates of its installation.
Manual control
The transition to manual control of lighting is carried out in the following cases:
- To repair the network in the daytime.
- To activate lighting in the event of a malfunctioning control relay.
- Turning on the lighting in situations when the control relay does not work according to the given conditions.
Switches are placed on the door or side surface of the lighting panel, due to which the transition to manual control is carried out. There are several ways to manually enable it:
- The switch of internal or external installation.
- Transferring the manual control key to one of the positions.
- Push-button control station - an industrial option.
The operation of the control relay depends on sensors located in the most convenient places. Often under the shields and lighting poles place a photo relay. Sensors are connected to the circuit with cables using terminal blocks mounted on a DIN rail.
If the load connected to the outdoor lighting panel exceeds the maximum permissible, then its connection is carried out through the starter. In this case, the relay is responsible for turning on the starter, which, in turn, turns on the lights.
Emergency lighting panels
Emergency lighting is a fully autonomous system with independent power supply, which extends from the input switchgear. Its connection is via an automatic reserve input system, powered by two independent sources.
Emergency lighting, unlike the working one, does not turn off manually: after the lighting board, switches are not installed. Such lighting either constantly works, or turns on automatically using magnetic starters or automation.
Shield Placement
The location and installation of lighting panels must meet the following requirements:
- Shields are installed at a distance of one meter from sewer communications, gas pipelines and water pipelines. In this case, the room in which the switchboard is located should not be flooded. If the operation of the lighting board and power cabinets is carried out in a room that can be flooded, then they are installed above the possible border of flooding.
- Much depends on the correct choice of switchboard. When selecting, the method of installing the lighting board - built-in or mounted, is taken into account. The built-in method is considered to be the most convenient, since the design installed in this way takes up a minimum of free space and is additionally protected from temperature and mechanical influences.
- When installing the switchboard yourself, you must consider the material from which it is made. His choice is based on the location of the shield: if it is made of combustible materials, then the shield itself must be made of steel. If the shield is installed on the base of non-combustible materials, then it can be made of low-combustible means.
- Outdoor lighting panels are installed at a height of 20 centimeters from the ground or concrete base. If there is a high probability of snow drifts, then the shields are installed on a special foundation.
- Equipped with pulse relays, counters and measuring devices, the outdoor panels are necessarily equipped with heating. The exception is the switchboards with devices that retain functionality at temperatures below 5 degrees.
Lighting board OShchV-12
The shield is made of metal, in the housing of which there is a mounting panel designed for installation of input and distribution equipment.
The OSHV shield has a high level of safety and reliability and distinctive features:
- the ability to install an input switch;
- stationary design with wall mounting.
Lighting board ShchRO-63A
A shield for receiving and transmitting electric energy in lighting equipment located in buildings of administrative, industrial and public purposes. It can also be used to protect circuits from overloads and short circuits. It is connected to three-phase electric networks and ensures the operation of four- and five-wire systems with grounding.