Drilling sockets & drilling flush-mounted sockets
In our short guide, you will learn everything you need to know before drilling sockets. Depending on whether you are extending an existing row of sockets or installing completely new ones, there are various things to consider. In addition to instructions for drilling sockets, we also provide useful and practical tips to make your work easier.
When we enter a room and want to turn on the light, we usually flip the switch intuitively without looking. This only works because light switches and sockets are installed at standardised distances from the wall and floor. These socket distances are divided into so-called installation zones . The installation zones are regulated in DIN 18015-3:
Light switches
Light switches are installedat a distance of 105 cm from the floor and 20 cm from the door.
Sockets on the floor
Sockets on the floor are installedat a distance of approx. 30 cm from the upper edge of the finished floor, also known as OFF. The upper edge of the finished floor refers to the distance from the floor after completion of the shell construction. Before, for example, screed is poured or the floor is installed, the socket distances are correspondingly larger and must therefore be taken into account.
Light switch and socket combination
If several light switches and socketsare combined in a strip, the switch and socket holes must be drilled71 mm from centre to centre (in accordance with the standard combination spacing specified in DIN 49075).
Switches or sockets next to an existing row
If a switch or socket is placed next to existing switches or sockets and these are not to be integrated into the row, the socket distance from centre to centre is 91 mm.
Row of sockets in a corner of the room
If a row of sockets is to be installed in a corner of a room, it must be positioned at a minimum distance of 50 cm from the corner of the room and 30 cm from the top edge of the finished floor.
Drilling sockets: Distances must be observed!
If the distance between the drill holes is incorrect, there is a high probability that the cover frame of the socket strip will not fit. In this case, it is advisable to use a drilling template to ensure that the drill holes are always at the correct distance. Practical drilling templates not only have the correct dimensions, but also an integrated spirit level, which makes marking even easier.
1. Determine the position of the switches and sockets
Sufficient distance must be maintained from chimneys, ventilation ducts and lightning protection systems.
The installation zones are shown in the following image in accordance with standard DIN 18015-3:
2. Check the wall for existing electrical and water pipes
To be on the safe side, a pipe detector can be used. This device can be used to locate pipes inside the wall.
3. Determine the required drilling depth by checking the installation depth of the sockets
Drill 1-2 cm deeper than the box so that there is still room for the cables.
First determine the wall thickness and also check whether there is anything on the other side of the wall to avoid breaking through or damaging existing pipes.
4. Determine the height of the first drill hole depending on the installation zone and mark it
However, start at a height of 30 cm on the floor.
Next to doors, the first hole is drilled at a height of 105 cm. Holes 2 and 3 are drilled below the first hole. If the row contains more than three switches or sockets, the holes from the fourth onwards are drilled above the first.
5. Position and align the drilling template and mark the drill holes.
6. Drill holes with a 68 mm box drill bit
There are different drill bits depending on the material to be drilled. The drill must be held perpendicular to the wall when drilling to avoid drilling at an angle.
7. Connect and insert the switches or sockets
This step should always be carried out by qualified personnel, as working on electrical wiring can be life-threatening.
8. Attach the cover
If the drill holes are deep enough and have been drilled straight, the cover plate will sit flush. If the cover plate does not fit completely and a shadow gap appears, it may be necessary to re-drill the hole or realign the box.
1. Allow sufficient distance from pipes and chimneys
Sufficient distance must be maintained from water pipes and chimneys. The heat here can greatly reduce the service life of the cable insulation. In addition, the installation should be carried out at a sufficient distance from lightning protection systems and telephone and internet lines.
2. Determine the number of drill holes in advance
The positions of the individual drill holes depend on both the installation area and the number of switches and sockets. If one to three switches and/or sockets are to be installed in the door area, the first drill hole should be made at a height of 105 cm. The other two drill holes follow below. If the switch/socket combination consists of more than three switches and/or sockets, the drill holes from the fourth hole onwards are arranged above the first hole.
3. It is essential to maintain the correct, standardised distance between the drill holes
To achieve a clean result, it is essential to ensure the correct spacing when marking the drill holes. If you want to save yourself the trouble of measuring with a folding rule and aligning with a spirit level, you can use a suitable drilling template. To ensure that the drill hole positions are clearly visible during drilling, they should be marked with a clearly visible cross.
4. Pre-drill to ensure that the socket holes are not crooked
Beware of crooked drill holes: if the socket holes are drilled crookedly, the socket covers and panels will no longer fit. Crooked socket drill holes then have to be corrected with a lot of work.
To make drilling the socket holes easier and to prevent the drill bit from slipping during drilling, it is worth pre-drilling the marked drill holes with a 6 mm masonry drill bit. The drill must be held perpendicular to the wall so that the drill holes are not crooked.
5. Determine and measure the drilling depth in advance
The drilling depth depends on the switches or sockets used. These are available in different depths. This means that sockets with a shallow installation depth are also available for very thin walls. To ensure there is sufficient space for laying the cables, the drill holes can be up to 2 cm deeper than the socket used.
6. Do not damage existing cables
How thick is the wall? What is on the other side of the wall? Are there any cables laid there? These are further questions that must be clarified before starting work. If existing cables are damaged when drilling for sockets, this will result in unnecessary and sometimes lengthy construction work. It is therefore better to check carefully beforehand and only drill after sufficient inspection.
7. Use the right mounting materials
Once the holes have been drilled, the boxes can be inserted. Cavity wall boxes are usually fitted with metal tabs that are used to secure the box in place. Flush-mounted boxes are inserted using electrician's plaster or cement mortar.
Important: Mounting foam should not be used to insert the boxes. Common mounting foams are highly flammable and do not provide sufficient strength to hold a socket firmly in the wall. The boxes should be as flush with the wall as possible to avoid a shadow gap.
8. Extending rows of sockets with precise spacing
To add another socket to an existing row of sockets or switches, the drill hole must be positioned exactly 71 mm from the centre of the existing socket. Without tools, this can be a very tricky task. Drilling templates are available for this purpose, which can be mounted on existing sockets.
The right socket drill bit or flush-mounted socket drill bit
The choice of socket drill bit depends on the material to be drilled. For example, a different drill bit is required for a drill hole in a wooden wall than for a plasterboard or stone wall. A bimetal hole saw is recommended for drilling into plasterboard walls. These can usually also be used for holes in wooden walls, although diamond socket drills are also available for wooden walls.
A diamond-tipped drill bit is always required to drill a hole in masonry. If the masonry is very hard, impact-resistant drill bits can be used. These allow drilling with a hammer drill.
The diameter of the drill bit for flush-mounted sockets is 68 mm, the same as the diameter of the hole saw for plasterboard walls.
Once the holes have been drilled, the boxes can be inserted. Cavity wall boxes are usually fitted with metal tabs for securing the box in place. Flush-mounted boxes are inserted using electrician's plaster or cement mortar. Mounting foam should not be used for inserting the boxes. Common assembly foams are highly flammable and do not provide sufficient strength to hold a socket firmly in the wall.
The boxes should be flush with the wall as far as possible to avoid a shadow gap. To add another socket to an existing row of sockets or switches, the drill hole must be positioned exactly 71 mm from the centre of the existing socket. Without tools, this can be a very tricky task. Socket drilling templates are available for this purpose, which can be mounted on existing sockets.
FAQ – Frequently asked questions about drilling sockets
The distance between two sockets is 71 mm if they are in a row. If the sockets or switches are to be installed individually, the distance is 91 mm.
A socket drill consists of a drill bit and a drill bit that is screwed onto it.
A flush-mounted socket is a plastic housing in which the inner workings of a socket or switch are installed. The connection is also made in this housing.
The drill hole diameter for switches and sockets is 68 mm. The type of drill bit depends on the material to be drilled. To drill sockets in concrete, you need a diamond drill bit. To drill in tiles, you need a tile drill bit. To drill sockets in wood, you need a hole saw (a drill bit with saw teeth).
For drywall, 68 mm is often used, and for flush-mounted boxes that are installed with plaster, 82 mm is often used.
A socket drilling template is a tool that makes it easier to maintain the correct distance.