Installation of electric meters and wiring to them. Scheme, description

ENCYCLOPEDIA OF RADIO ELECTRONICS AND ELECTRICAL ENGINEERING
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Installation of electric meters and wiring to them. Encyclopedia of radio electronics and electrical engineering

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Encyclopedia of radio electronics and electrical engineering / Electric meters

Electricity metering in domestic conditions is carried out single-phase electricity meter (Fig. 49).

Installation of electric meters and wiring to them
Rice. 49. Single-phase electric meter: Ф - phase wire; N - neutral wire.

Electric meters should be installed in places that are easily accessible for inspection and taking readings of electricity consumption. They are installed in dry rooms. The temperature in the room where the electricity meters are installed, in winter and in the off-season, should not be lower than 0 °C. Electric meters are installed in cabinets, on panels, shields, in niches, on walls that have a rigid structure. It is allowed to mount electric meters on wooden, plastic, metal shields. Electric meters are installed in such a way that the distance from the floor of the room to the terminal box of the electric meter is from 0,8 to 1,7 m. Sometimes you can install the meter at a height of 0,4 m from the floor. If there is a danger of mechanical damage to the electric meter or it is installed in a place accessible to unauthorized persons (passage, stairwell, etc.), then it must be installed in a lockable cabinet with a window at the level of the dial. At the same time, the designs and dimensions of cabinets, niches, shields should be such that convenient access to the terminals of electric meters and current transformers is provided and they can be easily replaced. The electric meter is installed strictly vertically. The slope in any direction is allowed no more than 1 °. The electric meter is attached so that you can easily take its readings.

In the electrical wiring to the electric meter, soldering of wire cores is unacceptable. When installing electrical wiring connected directly to the electric meter, a supply of wires with a length of at least 12 cm should be left. The insulation or sheath of the neutral wire of the electrical network in a segment of at least 10 cm in front of the meter must have a distinctive color compared to the phase wire.

In case of replacement of the electric meter, its repair or repair of the internal electrical wiring, it is necessary to provide for the possibility of power outages. To do this, a switching device, fuse or knife switch is installed between the electric meter itself and the input point at a distance of no more than 10 m. It should be possible to remove voltage from all phases connected to the electric meter. When installing a three-phase meter (for example, in the presence of machines or equipment with electric motors), it is necessary to obtain permission from the energy supply organization. A three-phase meter can only be installed in addition to a single-phase one, because only equipment operating from a voltage of 380 V can be connected to a three-phase meter; all household appliances and lighting operating on a voltage of 220 V are connected to a single-phase meter. Install a three-phase meter and a knife switch in front of it (a knife switch is required) in a rigid metal cabinet.

Connection of internal wiring to electric meters is carried out according to the scheme indicated on the reverse side of the meter. The connection is made with wires with a cross section of at least 4 mm2 if they are copper, and at least 2,5 mm2 if they are aluminum.

Before installation, electricity metering and distribution devices (meters, switching devices) must be checked and sealed by energy supervision authorities.

If several connections are required with separate electricity metering, then inscriptions indicating the connections should be made on the panels of the electricity meters.

At a distance of no more than 10 m along the length of the electrical wiring, it is necessary to install a protection device. If several electrical wiring lines equipped with protection devices depart from the electric meter, then a common protection device is not required.

In apartment buildings, the connection of electricity meters to the input of power lines is carried out according to a different scheme. The cable enters the introductory box; as a rule, the introductory box is located in the stairwell or in the basement. Fuses are installed in the box, which are responsible for preventing short circuits in case of overloads or accidents on the line. On fig. 50 letters A, C show the terminals of the electric meter, to which the input wires should be connected, and the letters B, D - the clamps to which the wires going to the consumers of electricity are connected.

Installation of electric meters and wiring to them

Installation of electric meters and wiring to them
Rice. 50. Electrical circuit for connecting the electric meter to the 380/220 V network: a - electrical circuit; b - scheme of a single-phase electric meter; FU1, FU2 - fuses; QF, QF1, QF2, QF3 - circuit breakers; SB1- SB3 - switches; Wh - electric meter; XS1, XS2 - plug sockets; XS3 - socket outlet with earthing contact; 1 - zero protective wire; 2 - zero working wire; 3 - the body of the electrical appliance; 4 - electric meter housing.

The wires from the entry point are directed up the risers (voids of building structures). A switchboard is installed on each floor and branches of the electrical line are already produced from it to each apartment. In front of the electric meter, which is installed on the panel, it is necessary to install a disconnecting device (knife switch, two-pole switch), which ensures that the wires of the mains supply are disconnected in the event of a current short circuit in the apartment.

Each installed electric meter must have on the screws fastening the casing of the electric meter, seals with the stamp of the state verifier, and on the clamping cover - the seal of the energy supply organization. Newly installed three-phase electric meters must have state verification seals with a prescription of no more than 12 months, and on single-phase electric meters - no more than 2 years.

Approach to electricity meters should be free. It is not allowed to place any objects on the electricity meter.

Individual electricity meters can be located here, on a common switchboard, or located directly in the apartment. Often, not one, but several independent group lines are introduced into one apartment, for example: for the residential area of \u51b\uXNUMXbthe apartment - one, and for connecting an electric stove, a washing machine, that is, for an economic zone - another, more powerful line (Fig. XNUMX).

Installation of electric meters and wiring to them
Rice. 51. An example of the wiring of an apartment in the presence of two independent lines.

It is not difficult to determine which electrical installation devices (sockets, switches, etc.) belong to one of the lines, and which to the other - this does not even require any measuring tools and devices: you need to turn on all the lamps in the apartment, and to each of the sockets connect some household appliance that constantly consumes electricity (tape recorder, vacuum cleaner, table lamp, but not a refrigerator, because periodically disconnecting the compressor from the circuit will confuse the study of the electrical circuit); next, turn off one of the fuses or circuit breakers on the group panel and mark de-energized household appliances and lamps - they belong to the same line.

If, in order to de-energize a separate line, it is required to disconnect not one, but two fuses, then this line is protected by two fuses.

Author: Korshevr N.G.

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