Chasing walls for wiring: tools, rules

One of the most common ways to install electrical wiring is hidden. This is when wires and cables are laid in grooves made in the wall, floor. The process of making grooves is called chasing, and these grooves are called “strobe” or “shrub”. How to do wall chasing for wiring, according to what rules, what tool to use, and we’ll talk further. 

Gating rules

Laying wiring in a strobe refers to a closed installation method. The remaining hole is then sealed flush with the wall, after which finishing materials are applied. That is, then it is difficult to determine exactly where the wiring goes. From an aesthetic point of view, this is good, but from a practical point of view, it brings obvious inconveniences: when working with drilling holes in the walls, you have to take into account that there is wiring somewhere. You can find it with the help of special wiring detectors, but the gasket itself must be predictable. To do this, we have developed a number of rules that must be followed in apartments and houses:

• Strobes are made only vertically and horizontally. Inclined lines are possible only when laying in visits with sloping walls – in attics, residential attics, on stairs. In this case, the strobes are made parallel to the inclined surface.
  

• From engineering networks – gas pipes and heating pipes – grooves for laying wiring should be at least 50 cm away.
• When laying the strobes under the ceiling, 15-20 cm recede from the corner down. If it is necessary to lay another branch during the modernization of the wiring, it is also lowered by 15-20 cm.
• From the corners and openings (window and door) must retreat at least 10 cm.
• The depth and width of the strobe depends on the dimensions of the wiring being mounted, but usually up to 20 mm is enough. The maximum allowed is 25*25 mm. This depth may not be enough if the wire is laid in a corrugated sleeve or a metal tray. In this case, the groove can be slightly deepened. But, if there is a layer of plaster on top, you can not deepen it – a few millimeters will easily close.
  

• If there is a metal frame in the wall, it cannot be cut categorically. It is usually about reinforced concrete structures. In them, the carcass is a steel wire, which is located at a depth of 4-5 cm. So 2 cm is normal, but even when laying cables of large diameter, metal cannot be broken
• If there is a sufficiently large layer of plaster on the wall, the wires can be laid in the thickness of the solution. This is easier than making a groove in the base material.
• When approaching a socket or switch, the depth of the strobe can be slightly increased so that the wire fits well into the junction box. But in this case, it is impossible to break the metal frame.

These are the general rules that relate to wall chasing for wiring.

Chasing tool and technique

There is an old-fashioned method – a chisel and a hammer, which does not require electricity, but takes a lot of time and effort. By hitting the chisel, its tip is driven into the wall, picking off some of the material. The process is then repeated many times. The speed of laying the strobe in this way is very low. It can be more or less successfully used for shaving plaster. With any other materials there will be big problems.

Work faster with power tools:

• The best option is a shredder. This is a special tool with two saw blades, which set the parameters of the strobe. That is, in one pass you get two parallel lines in the wall. A certain amount of material remains between them, but then it is quite easily knocked out with a puncher with a special nozzle – a spatula. The advantage of working with a wall chaser is a smooth strobe, no dust, since it is possible to connect an industrial vacuum cleaner. The disadvantage is that the equipment is very expensive, so it is not worth buying it for one-time work. The way out is to rent it in a specialized store.
  

• Hand circular saw, angle grinder (angle grinder) or grinder. You can make cuts in the wall with this tool, but working with it on a concrete or brick wall is very dangerous. Any inhomogeneity of the material being cut – stone, metal, voids – can lead to the fact that the tool will break. In this case, the likelihood of serious injury is very high. When working with wooden surfaces, it is better to use a hand saw.
• Perforator. This tool is usually used at the final stage – between two laid strobes, the material is removed either with a chisel or a perforator with a spatula. You can, of course, immediately break off pieces of the wall along the intended line, but in this case the groove will turn out to be a curve. If that doesn’t scare you, you can do it this way.
  

• Drill. This is not the best way, but better than manually chasing with a chisel. A series of holes of large diameter are drilled along the intended line, not far from each other. Great depth is not required here – no more than 20 mm, so it does not take much time. The resulting chain of holes is turned into a groove using a perforator or a chisel and a hammer.

These are all the methods that are used for chasing walls for wiring in concrete or brick walls. If it is necessary to make grooves in wood or foam concrete, there are certain differences.

How to make strobes in wood

In principle, you can work with all the tools described above, except for a puncher. The main difference is that chisels are used instead of chisels, but the very essence of the work remains the same. First, two parallel cuts are made, and the wood between them is removed with a chisel. But besides these tools, there are a few more specific ones:

• A circular saw. With a sufficient level of proficiency with this tool, a strobe in a wooden wall can only be made with a circular saw – in two or three passes, gradually expanding the cut to the required size.
• Frazier. You can also make a neat strobe with a manual milling cutter. To do this, you can fix a flat bar as a guide on the wall and make a recess along it, which is then expanded to the required size. (You can read about working with a manual router here.) There is even a special cutter (pictured on the left), but you can also work with a regular one to form a groove or a side one (on the right, but it’s not very convenient for her to work in this case).
  

So there are more opportunities for chasing in wood. In this case, if there is one of these tools, it is better to work with it – they are designed for wood and are most convenient.

How to make grooves for wiring in aerated concrete

When laying walls made of aerated concrete or foam concrete, they have to be reinforced. The reinforcement is placed in cut grooves – strobes. To do this, there is a special shtrobroez for aerated concrete. This is a metal pipe with a handle and a protrusion at the other end.

The process is very simple – you need to pull the tool, pressing it to the surface. Foam aerated concrete is easy to process, so there are no difficulties. You can, of course, use a circular or angle grinder, but at the same time there will be many times more dust, which is not pleasing in the room.

Chasing brick walls

If we are talking about laying wiring in a house where finishing work has not yet been carried out, then usually a strobe is not made on brick walls. A flat cable with conductors of the desired section is fixed over the wall, which is then covered with plaster. Usually it has a thickness of at least 3 cm, which is more than enough for laying 3 * 2,5 or 3 * 4 cables. The big ones are rarely used anyway.

If, for some reason, this option does not suit you, or you want to lay cables in a corrugated hose, the wall chasing for wiring occurs in exactly the same way and with the same tools as for concrete. The only difference is that the brick is cut easier and faster.

Is it possible to ditch load-bearing walls

In theory, when repairing electrical wiring in an apartment, it is necessary to order a project. When developing it, the presence and location of load-bearing walls, and the possibility of laying shtrabs in them, are taken into account. As a result, a plan is issued, which indicates exactly where and what needs to be laid, how wide and how deep each groove should be. It remains only to do everything exactly.

If you are concerned about damaging the load-bearing walls during work, apply for a permit with the CC. They should pick up the paperwork and see how big the margin of safety is in your house. Most likely, permission will be given.

But so few people do. Basically, they draw a plan (if they draw), then they transfer it to the walls, and work begins. If the chasing of walls for wiring is carried out in this order, grooves of more than 20 mm in depth and width are not made in the bearing walls and they simply hope that nothing will be damaged.

Chasing walls for wiring: order and safety

Since the wiring must be carried out according to certain rules (described above), it is first worth drawing a plan, considering the placement of all sockets and switches. It is advisable to draw a plan on a scale, you can do this in special programs for drawing diagrams, or you can do it on paper. Then points are transferred to the walls where sockets, switches, chandeliers, sconces, junction boxes are installed. After that, they are connected into a single system by a system of lines, along which strobes are then laid. After that, using the wiring detector, check whether there are already existing wiring under the laid routes (if you are doing repairs), make adjustments if necessary. Only after this, the wall chasing for wiring actually begins.

First, you can use a drill and a special nozzle – crowns of a suitable diameter – to drill holes for the installation of sub-sockets and mounting boxes. Then you can start shredding.

But it is worth remembering that making grooves for wiring in walls made of brick, concrete, wood is a dusty and noisy business. Therefore, it is necessary to work during the hours allotted for noisy work – during the day, on weekdays, with a break for lunch – small children can rest.

Before starting work in a particular room, it is advisable to hang the entrance with a wet cloth – dust will fly less. You need to work in a respirator and goggles, or better, put on a protective shield that will cover your entire face (but do not refuse a respirator). It is also worth putting on tight clothes that cover your arms and legs – when working, particles of the material of the walls fly off, and the smallest ones quite noticeably cut the skin, and the eyes can be seriously damaged.

These are the basic safety rules when chasing walls for wiring, but do not forget about the rules for working with power tools, especially such as angle grinders and hand-held circular saws.

Another tip: after you have wired, carefully measure all the distances and plot them on the plan. It will come in handy during repairs or if you need to nail / hang something in places where wiring can pass.