Corrugated cable conduits 450N and 750N are manufactured and tested in accordance with EN 61386-1 and EN 61386-24. With reference to these standards, each European country issues its own product marking: two examples are the IMQ marking in Italy and the NF marking in France. Cable conduit pipes are manufactured in accordance with the “Directive 2014/35/EU relating to electrical equipment designed for use within certain voltage limits” and CE-marked, so they do not fall under the ‘Construction Products Regulation’ nr. 305/2011.
Cable conduits must be identified with a durable and legible marking applied to the surface of the conduit every 1 to 3 metres.
The marking in accordance with EN 61386-1 and EN 61386-24 must contain the following information:
The tests required by the above-mentioned standards and often stated in the corrugated pipe data sheet are:
The main characteristics for the choice of corrugated pipe for regulation electrical installation are resistance to compression and impact.
Compressive strength is the most important characteristic since the pipe is buried and consequently subjected to the overlying static load. On top of this there may also be any load due to above-ground stresses such as the weight of vehicles. As defined by the standard, the corrugated cable conduit sample is crushed between two plates so as to deform the inside diameter by 5%; the force required to achieve this crushing must exceed 450N or 750N.
While compressive strength is a property that accompanies the cable conduit during its life, the impact test, on the other hand, serves to guarantee the duct during installation. The test simulates the accidental stresses caused by stones in the ground falling onto the surface of the structure during the burial phase. Therefore, the soil layer adjacent to the cable conduit should be free of stones larger than 80-100 mm in diameter. To test this characteristic, the sample, conditioned for 2 hours at -5°C, is hit by a dart with a fixed weight of 5 kg from a variable drop height depending on the nominal diameter of the corrugated pipes (300 to 800 mm height). At the end of the test, there must be no gap allowing water to pass from the inside to the outside.