Reconstruction of internal electrical networks of the kindergarten State Department

General Data

The working design of the electrical installation was developed on the basis of the technical assignment for the design of the customer and the power certificate No. 06 of 11.12.2006 in connection with the reconstruction of internal electrical networks. The project solved the issues of the construction of internal electrical networks, electrical lighting.

1. Design Input

1.1 General characteristic of the electric power consumer

Electric consumer existing non-residential building MSOU Kindergarten №? at the address: St. Petersburg. The permitted power of electric receivers is 151.2 kVA.

The walls in the rooms are brick, painted in light tones, the ceilings are whitewashed.

Cold and hot water supply, centralized heating. Pipelines for hot, cold water supply and heating at the inlet are metal, for the building - plastic.

1.2 Power Supply Characteristics

Power is supplied from transformer substation TP6.

The category of reliability of power supply is II. The most responsible electric receivers - the heat unit panel, emergency lighting, security and fire alarms - are powered through the ATS device and are classified as category I electric receivers. The remaining electric receivers are classified as category II electric receivers.

1.3 Characteristics of electrical load

The electrical load is created mainly by the internal lighting system, process equipment of the food unit and laundry, electric storage water heaters.

2. Technical solutions for electrical installation

2.1 Power supply

Power supply of the facility is provided from cable kiosk No. 3, which is powered from transformer substation TP6 via two existing mutually redundant cable lines. Each cable line is executed by two cables of the APV (3h95+1h50) brand. Cable conductors cross section is checked by permissible long-term current and voltage losses.

2.2 Electrical networks

The existing main distribution board (MCC) is used to enter and distribute electricity to consumers. GRF is made in cabinets of GShVU2 type and consists of four panels, the degree of protection is IP31. SGN is installed in an existing separate room - electric panel, which is located in room No. 147.

Electric receivers are combined into groups in accordance with their technological purpose and are connected to the corresponding distribution boards. Panels: RDT (in electrical panel), MCC - existing.

Distribution and group networks of five - and three-wire, are made by a cable of the VBGng brand. Cables are laid mainly open in corrugated PVC pipes and hidden in floor preparation in rigid PVC polyethylene pipes. Sections of cable lines to be laid are also laid in PVC pipes.

Group lighting networks and socket lines are made by IWGng cable open in corrugated pipe behind suspended ceilings.

All connections and branches shall be made in branch boxes by welding, soldering, sealing in sleeves, terminals or by means of special clamps. When plugs or other electrical receivers are connected in a "chain," they are connected by a branch from the group network.

Passages through walls shall be made in pipe sections with subsequent closing of gaps between cables and pipes by easily removable mass from non-combustible material.

2.3 Electric lighting

The design provides for the following types of lighting: working; emergency (evacuation and duty);

As light sources are accepted: fluorescent lamps; filament lamps.

Light and illumination sources are selected taking into account provision of regulated illuminations on the basis of SNiP 23.0595 "Natural and artificial lighting," design standards SP311102003 "Design and installation of electrical installations of residential and public buildings."

In the bedrooms there is a duty room (night lighting) connected to the emergency lighting network.

Emergency lighting is supplied by reliability category I through ATS.

2.5 Electricity metering

Multifunctional microprocessor three-phase electric energy meters Alpha A1700, AV10RLP14B, 3x220/380, 5 (10) A, accuracy class 1.0, connected to the inputs through test terminal boxes and current transformers T0.66 200/5A, accuracy class 0.5S, are used to take into account electric energy consumption. The design of the introductory distribution panel GVU2 provides for the installation of counters in a separate cell with a locking door. Counters are programmed in single-tariff mode.

2.6 Protective electrical safety measures

The following measures are provided for protection against electric shock:

1. Automatic power-off of emergency network sections. Circuit breakers responsive to overcurrent are used for automatic power-off; differential automata responsive to supercurrent and differential current. Automatic shutdown time does not exceed 0.4 s.

2. Protective grounding (bushing). All open conductive parts are connected to the neutral of the power supply by means of the PE conductor. A separate feeder cable core is used as the PE conductor.

3. The main potential equalization system. Copper bus 75x5x350 is used as the main grounding bus. GZSh is installed in GRSh (PE bus). Metal pipes of utilities included in the building are connected to the GZSH: sewage, water supply; metal parts of ventilation systems; grounding device of lightning protection system.

3. Organization and execution of electrical installation works

Construction and installation works shall be performed in accordance with the requirements of SNiP 3.01.01.85. "Organization of construction production" and SNiP 3.05.0685 "Electrical devices." During the works, it is necessary to carry out measures to organize safe work using construction mechanisms and small mechanization facilities. During and after completion of electrical installation works, documentation is drawn up in accordance with VSN 12390 "Instruction on preparation of acceptance documentation for electrical installation works."

3.1 Installation of electrical installation of the aircraft

Prior to the commencement of work, working documentation shall be received, a work schedule agreed with the customer has been developed and deliveries of necessary materials, products and equipment have been planned .

Hidden wiring is laid parallel to architectural and construction lines. Horizontal cable and wire distances from floor slabs shall not exceed 150 mm. All cable and wire connections shall be trimmed in sleeves or clamps in junction boxes.

Cable and wire passes through walls shall be made in steel pipe sections. The gaps between the cable and the pipe should be sealed with an easily removable mass of non-combustible material.

Wires and cables shall be marked at the beginning and end of pipes, as well as at the points of branches and their connection to electrical equipment. Connection and branch points shall be accessible for inspection and repair. At points of connection the cables shall not experience mechanical forces. Contact connections shall meet the requirements of GOST 1043482.

Wire and cable headers shall be provided with a margin of wire or cable for reconnection.

General safety requirements as per SNiP III480 (2000), SNiP 120399, GOSt 12.3, 3284 (1990) SSBT shall be met during works performance and personal protective equipment provided by GOST 12.4.01189 shall be used.

Based on the results of electrical installation of the building, the following documents shall be drawn up by the electrical installation organization:

- certificate of technical readiness of electrical installation works;

- acts on hidden works;

- act of inspection of the lighting system.

4. Organization of electrical installations operation

1. The boundary of the division of the balance sheet and operational responsibility between the power supply organization and the consumer is defined by the specification for the technological connection of electrical installations .

2. The Consumer's electrical installations shall be operated by trained electrical personnel.

3. Maintenance personnel shall have operational and technical documentation (according to CTEEP, c.1.8).

4. All used household appliances shall comply with GOST 275700 "Safety of Household and Similar Appliances."

5. Electric lighting devices shall be operated in accordance with the requirements of PTEEP, c.2.12.

6. To operate electrical installations in the organization, a person responsible for the electrical plant must be appointed.

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