Boxes for electrical wiring: dimensions and mounting method

If you compare the open and hidden type of electrical wiring in the wall thickness, then from the point of view of fire and electrical safety the second is preferable. Once I did and forgot, because accidental damage to it is practically impossible. Nevertheless, in a number of cases it is necessary to perform wiring in an open method. For example, in a room from a log or a beam, it is rather costly to hide the wire in the wall. An excellent solution is the box for electrical wiring. Even an aspiring home master will cope with their installation.

What are the boxes for electrical wiring

Imagine that you need to wiring the network on the premises, but you can not embed the cable in the walls. The power wiring executed openly on insulators, from the point of view of appearance, will not fit into every interior. If the wire is hidden in the corrugated tube, it is also not too beautiful, and is more suitable for utility rooms and productions. However, there is a way out - this is a box for electrical wiring. They are a special profile with a section in the form of the letter "P", made of plastic, aluminum or galvanized metal. It is fixed in one way or another on the surface, cable-conductor products are laid in it, and the top is closed with a lid, which is held by snap locks. Boxes for electrical wiring are implemented with standard "sticks" 2 m long. Regardless of the material, this design does not support combustion.

We note that in addition to the simplest U-shaped section, there are more complicated modifications in the form of "III". That is, by installing the boxes for wiring, during the laying it is possible to separate the lines by laying them in separate sections of a single structure. In this case, the covers can be separate.

How to choose a cable box

The most inexpensive solutions are plastic modifications. In addition, compared to metal, they are more simple to fit during installation. The plastic wiring box has one more advantage: in case of damage to the cable insulation, the dangerous potential will not spread over the surface. When buying it is very important to choose the correct number of boxes. Usually the previously measured yardage should be exceeded by 10-20%, because otherwise there may be a situation where the purchased box is not enough and you will have to look for an additive somewhere. There are also accompanying accessories on the sale: rotations, corners, tees, allowing to give a finished look to the wiring performed. These elements must also be purchased. Particular attention is required for the box for electrical wiring under the tree, because when there is a shortage of any elements of the construction, pick exactly the same in another outlet is almost impossible because of the differences in color.

Before going to the store

We recommend using the following algorithm of actions preceding the immediate purchase:

- to think over the places of installation of sockets, switches, lamps and other consumers, and also their quantity;

- draw a layout diagram for the premises;

- Determine the required footage - the stock is mandatory;

- provide furniture (rotations, external and internal corners, junction boxes);

- take into account the size of the boxes for electrical wiring and choose the most appropriate, depending on the type of cables used; In addition, the size affects the number of sections in the product;

- decide how to fix on the surface, stock up on the necessary tools;

- to think, whether metal boxes for electroconducting are necessary or it is possible to do with plastic variants. The undoubted advantage of iron trays is their strength. They can even run a high-voltage cable. A grounding contact is provided. The plastic wiring box still does not allow placing a large number of cables and wires, since it will either bend or require too frequent fastening to the base.

Locks and material

The retainers holding the cover can be placed on both the two and one side. In the latter case, a special groove is provided instead of the latch. Two-way fixation is more reliable, so it is better to choose such models. "Disease" products of some manufacturers - unreliable fastening of the lid, because of which for closing it is necessary to knock a little on it. Here also the problems begin: depending on the plastic used, the boxes often deform (burst, bend, etc.). Therefore, when buying it is very important to try to close the chosen model, and not solve unusual tasks during installation. So, there were cases when in the final stage of laying the lid in the points had to "sit on the glue". Metal boxes for wiring in this respect are much better than plastic ones.

Dimensions

Let's consider more in detail what kind of boxes for electrical wiring are plastic. Their dimensions are as follows: 22 × 10 mm - 40 × 16 mm (conditionally called mini-channels); 12 × 7 mm - 16 × 12 mm (microchannels); 100 × 40 mm - 100 × 50 mm (the most common standard); Up to 200 × 80 mm (large). There is a technique that allows you to accurately determine the desired size. To do this, use the formula:

S = (N × d2) / K,

Where S - required section of the box, mm.kv .; N - the planned number of cable routes, pcs; D - cable diameter, mm; K - correction factor, the use of which is necessary in order to prevent too dense laying (0.45).

Having received the result, it is necessary to choose the nearest box of a suitable size. Choosing plastic boxes for wiring, the dimensions of which are less than required (calculated), it is important to understand that the temperature regime of the cable cores will be broken, and the cover can be loosely locked and flipped when accidentally touched by such a tray.

Installation work

After measuring the strip of the required length, a mark is made on the box and cut using a hacksaw for metal (regardless of the material), an acute mounting knife or even side cutters. This operation should be performed on the assembled box, including the tray and the closed lid. The transition "wall-wall" or "wall-ceiling" is better to perform with the help of special angles. If they are not, then in not very noticeable places sometimes use a special technique: on one tray the base is cut, and on the other - the lid, and combine them. True, a straight angle can be obtained in this way only if a cover resistant to kink material is used.

On the surface a simple marker is drawn with a simple pencil, indicating the future location of the box. It is recommended to use a level and a plumb line. On a level surface, the box can be glued with liquid nails, however, further work is possible only after complete drying. To the wooden wall, the tray is easiest to attach with self-tapping screws and a cordless screwdriver. Brick and concrete foundations require a different approach: in the bottom of the tray holes (2-3 mm) are made every 0.5 m. Then the box is applied along the marked level to the wall and marks are placed through the holes. In them, with the aid of a drill of percussion action or a perforator, channels are drilled under the dowels. Further installation is in the fasteners with screws.

In principle, nothing complicated in the installation of cable boxes there, and this work is able even for an unprepared person. The main thing is not to hurry up anywhere, carefully measure everything and think it over. Especially if the work is done for the first time.

Cable production

Sometimes it is very difficult to perform such a simple task as laying a cable route in a box. The line bends, "snakes", propels the inside of the lid, etc. Especially "the cables", whose veins are made of rigid single conductors, have become "famous" in this respect. Therefore, they must be carefully leveled and bent. In addition, some boxes have additional longitudinal partitions, simplifying the laying of such "naughty" conductors. The easiest way is to stretch all the lines at once and cover each meter covered with the lid as it is laid. Reduce the visibility of joints will help reception, described by us above: pruning trays and covers, so that these lines do not match.

Recommended placements

The manual does not make any demands on the location of sockets, switches, lamps and the way of orienting cable routes. However, it is considered an unspoken rule to lead the lines horizontally and vertically, avoiding curves. In the case of concealed wiring, this simplifies the search for the fault location, and the outer boxes look more aesthetically pleasing. The distance from the ceiling to the track should be 150 mm, and from the window and the doorway an indentation of 100 mm is necessary. And, of course, it is necessary to provide intermediate junction boxes on the line, which will help restore the operability of the lines, if necessary.

General Tips

Since the distances between the walls at the ceiling and the floor often differ due to the peculiarities of domestic construction, do not cut off the cable box for top mounting by taking measurements down. In addition, the angles may seem straight from the side, and when trying to install a transitional corner it turns out that this is not the case. Carrying the transition of the route through the wall, you need to place a tube there (metal plastic is suitable) to be able to replace the site or "pull" the track. All these nuances must be taken into account.