Knowledge
How deep should an underground cable be buried?
Burial depth, cover and which cable may go in the ground.
At least 0.5 m: that is what NEN 1010:2020 requires for cable outside buildings, unless the cable is additionally protected. In practice 60 cm is usual for low voltage, and more under roads and for medium voltage. In Belgium 0.60 m applies. Lay the cable in clean sand with cover tiles or warning tape above it, and choose a proper underground cable: VO- or VG-YMvKas in the Netherlands, NYY in Germany and EXAVB in Belgium.
An underground cable has to lie deep enough that digging, gardening or traffic does not reach the cable. NEN 1010:2020 sets a lower limit for this: outside buildings a trench depth of at least 0.5 m (clause 522.8.10.1). Less is only allowed if the cable is additionally protected against damage. For low voltage, 60 cm is the usual practice. Under driveways, under roads and for medium voltage the cable lies deeper. On public land, the municipality, as manager of the land, and the network operator prescribe the route and the depth. If you are installing in Belgium, 0.60 m is the minimum (AREI, Book 1, 5.2.9.2). If that is not possible, the cable goes into a protective duct over its full length.
Place a warning above the cable: cover tiles or a warning tape (red for electricity), usually 20 to 30 cm above it, so that anyone digging sees the warning before the spade reaches the cable. Lay the cable in a bed of clean sand, free of stones or rubble that could press through the sheath.
Not every cable may go into the ground. Choose a cable built for it. In the Netherlands that is VO-YMvKas or VG-YMvKas, with a steel braid or armour against digging damage. In Belgium you choose EXAVB, an armoured cable that may be laid directly in the ground. In Germany NYY-J is the usual underground cable for installations. Network operators and industry there often use NYCWY or NAYCWY, with a copper conductor around the cores. Under NEN 1010:2020, unarmoured installation cable such as YMvK may go into the ground, provided it lies deep enough. The 2015 edition, which still applies by law, asks for extra protection, such as a duct. Agree it with the client or the inspector beforehand. YMvK cannot withstand an excavator bucket, so lay the cable in a sand bed with cover tiles or in a duct. Flexible cord and rubber cable do not belong there at all.
Under a driveway or paving there is extra load. In that case, choose VG-YMvKas with the heavier armour, or lay the cable in a duct. At crossings with other services and when pulling into ducts, extra clearances and requirements apply; NEN 1010 and the network operator prescribe them.
Q Cables holds VO-YMvKas Dca up to 4×6 mm² and VG-YMvKas Dca up to 4×240 mm² in stock, cut to route length if you wish. With your enquiry, give us the route, the length of each cable run and what the cable crosses on the way; that decides whether VO is enough or whether it becomes VG with the heavier armour.
Does a driveway, paving or another service cross the route? Send the cover you are working to and what is crossed. We will tell you whether a duct is needed and which version fits. Our advice is an aid; the responsible designer or installer checks it and makes the decision.
In our cable selector, Cable selector tab.