Street billboard at the site

Putting an electric panel on the street is not such an absurd idea as it might seem. The reasons for this technical solution are as follows:

1. Energy sales organizations often insist that a meter for energy consumption and, accordingly, introductory house electrical panel, located within the reach of the inspector. This is especially true for large suburban residences, where the owners can relatively easily “hide” in the house an additional input past the counter with known goals. On the other hand, the shield on the street support is clearly visible from all sides and does not cause the inspector any doubt or suspicion.

2. In the same suburban residence, an opening electric shield can also be very impressive. And the desire to save on space and take out at least a meter and input device outside the house is understandable.

3. In the end, the switchboard may simply not fit into the interior of the living room, especially if the latter is a designer. In this case, you can not only take the shield to some utility room, but also go further by placing it on the street.

Well, and, of course, placing a shield on the street has its drawbacks. Here they are:

1. Despite the technical conditions from energy sales companies, an electric meter on the street may be a violation of clause 1.5.27 of the EMP, which states that electric meters can be placed in unheated rooms and street cabinets only if there is local heating that provides a positive temperature for the meter. And such a restriction is not always easy to observe.

Meanwhile, an induction electric meter at negative temperatures inevitably begins, simply put, to “lie”. Moreover, “lying” is not in favor of the subscriber, therefore Energosbyt is of little concern to this fact. For the subscriber, this is a significant minus.

2. To take readings from the electric meterlocated in a street billboard is not very convenient. Especially if it’s winter in the yard, and the shield is at a considerable height for security reasons in front of thieves and hooligans. The shield, standing high on a support, is inconvenient to repair and maintain: at least you cannot do without a stepladder.

3. Having a shield with group devices on the street, we will be forced to pull group lines from there. Moreover, the larger the house itself, the more these lines will be and the more impressive will be the "web" connecting the opening shield and the building. There is little good in this, even if the "web" is hidden in a pipe located underground.

Therefore, for a solid cottage, the option of placing group machines in a street billboard is no longer needed: such a technical solution is acceptable only for country houses, garages and other small buildings. And the advantages of a street shield, in which only an introductory machine and a counter are installed, are no longer so obvious.

Composition and electrical panel for outdoor installation

The structure of a street electrical panel, first of all, includes an input circuit breaker with two poles for a single-phase network and four or three poles for a three-phase network. An additional pole will be possible to use to completely disconnect the network and break even the neutral conductor. This will be useful in the event of a malfunction in the mains network itself, which, unfortunately, also happens sometimes.

The introductory machine provides not only the ability to turn off the network, but also protects it from current overloads. However, besides this, fire-fighting differential protection of the network is also necessary, which can be ensured by using a differential rather than a simple introductory circuit breaker. Another option is a separate RCD, which will be installed immediately after the introductory device. The value of such an RCD should be 100-300 milliamps.

After the introductory machine and differential protection device should be placed electricity metercalculated for the corresponding number of phases. If the load in the network does not exceed 100 amperes, then the counter can be directly connected. If the load is more than 100 amperes, then the meter will have to be connected via current transformers, which will lead to a significant increase in the size of the shield.

This is the minimum set of devices. It can be supplemented, for example, with voltage monitoring relay complete with shunt trip for opening machine. But besides this, it is necessary to include equipment in the shield to maintain a positive temperature in the winter. The simplest solution is a modular thermostat paired with special heaters for electrical panels, which are produced by most major manufacturers of electrical modular equipment.

In addition to the devices in this panel, you should place the zero PE and N buses connected by a jumper. If the shield body is metal (which is most likely for outdoor conditions), then it should be grounded by connecting to the PE bus. Using the copper wire with a cross-section of at least a cross-section of the input phase conductor, a re-grounding device located in the ground at the installation site of the shield should be connected to the same PE bus. Run grounding device it is possible from several steel vertical rods with a diameter of about 16 mm or corners of equal cross-section, interconnected by means of a welded steel strip 4 * 40 mm.

Since the input and the electric meter are, in the opinion of the power supply companies, deeply intimate things, the box in which this equipment will be placed must be sealed. In this case, the user should only have the opportunity to take readings and turn on / off switching / protective devices. The shield itself must be securely closed and locked with a key.

In addition, since the shield will be located on the street, it should have an increased degree of protection against external influences: usually at least IP54.

Installation of a shield on the street

The place for the installation of the street billboard usually becomes, after all, not a street in the literal sense, but a yard or a plot, in general, personal territory. Such a choice is made for reasons of basic safety.

To install the shield, an additional separate support is most often used, which becomes mandatory for long branches. If there is no such support, then you can build a rack of improvised materials. The shield itself must be firmly fixed in level, for example, with through bolts.

Energy sales companies often insist that a street billboard with a meter be mounted at a height of 3 meters or more. With this arrangement, safety is of particular importance: it is necessary to take into account the impact of the wind, and the fact that over time the fastening may become weaker.

It is better to enter the shield through intermediate insulators so that the input wire / cable, swaying, does not rub its insulation and pulls out. The outgoing line does not have to be made airy; you can put it in a pipe underground.

Alexander Molokov