European standards IEC EN 61386
EN 61386.1 General requirements. Concerning all conduit systems and accessories for electrical installations. It must be used with part 2 related to each product system.
EN 61386.21 Particular requirements for rigid conduit systems and accessories.
EN 61386.22 Particular requirements for pliable conduit systems and accessories.
EN 61386.23 Particular requirements for flexible conduit systems and accessories.
EN 61386.24 Particular requirements for conduit systems buried underground.
1st digit: compressive strength
1 – extra light (125 Newton)
2 – light (320 Newton)
3 – medium (750 Newton)
4 – heavy (1.250 Newton)
5 – extra heavy (4.000 Newton)
2nd digit: resistance to impact
1 – extra light (0.5 Joule)
2 – light (1 Joule)
3 – medium (2 Joule)
4 – heavy (6 Joule)
5 – extra heavy (20,4 Joule)
3rd digit: minimum working and installation temperature
1 – (+5°C)
2 – (-5°C)
3 – (-15°C)
4 – (-25°C)
5 – (-45°C)
4th digit: maximum working and installation temperature
1 – (+60°C)
2 – (+90°C)
3 – (+105°C)
4 – (+120°C)
5 – (+150°C)
6 – (+250°C)
7 – (+400°C)
The IK code indicates the impact resistance (in Joules) of the conduits at room temperature in compliance with the European standard EN 62262. The installer should choose a conduit with a specific IK code based on the type of installation.
WHICH IK CODE FOR WHICH INSTALLATION? (Some examples)
IK07: House exterior IK08: Gyms IK10: Underground car parks (over 100 m²) – Road tunnels (greater protection is required against fire)
IP protection rating
The IP rating, which complies with the European standard EN 60529, indicates the resistance of the CONDUIT system + FITTINGS to the penetration of external objects. The IP rating consists of two numbers: the first indicates the resistance to the penetration of solid objects (from 0 to 6) while the second defines the resistance to the ingress of water (0 to 8).
7th digit: resistance to the penetration of solid objects
3 – protected against the ingress of solid objects with a diameter = / > 2.5 mm. 4 – protected against the ingress of solid objects with a diameter = / > 1.0 mm. 5 –dust protected 6 – dust-tight.
8th digit: resistance to water penetration
0 – no protection 1 – protected against vertically falling water drops 2 – protected against vertically falling water drops (system tilted up to 15°) 3 – protected against rain 4 – protected against water splashes 5 – protected against water jets 6 – protected against strong water jets 7 – protected against the effects of temporary immersion in water
The insulating conduits for electrical systems that fall within the scope of the European Low Voltage Directive 2006/95/EC must comply with the requirements established by the new International/European IEC EN 61386 standards. The standards specify the requirements and lab tests to which the conduits must be subjected.
Compression and crushing test
1. The sample conduit is subjected to an increasing compressive load so that, at a given time, it reaches the force defined by the standard; the intensity of the force is measured in Newtons.
2. Once this force has been reached, the deflection level is measured, i.e. the difference between the original outer diameter and the post-test outer diameter. This deflection must not exceed the limits imposed by the standard.
3. Once the deflection has been measured, the force is removed and 15 minutes later, the so-called “self-recovery” capacity is measured: the difference between the original outer diameter and the post-test outer diameter should not exceed 10%.
E.g. ICTA 3422
The resistance to compressive strength is expressed by the first digit: 3.
The sample of ICTA 3422 is subjected to a force that reaches an intensity of 750N in 30 seconds: following this force, deflection of the sample must not exceed 50% (for ICTA 20 mm, for example, the reduction in diameter must not exceed 10 mm).
Recovery: for the ICTA diam. 20, the post-test diameter must be at least 18 mm.
Impact resistance test
1. The sample conduit and equipment are conditioned for at least two hours, at the minimum operating temperature (corresponding to the declared classification).
2. The sample is then hit by a hammer placed at a given distance set by the standard (the hammer mass also changes according to the declared classification).
3. The sample subjected to this shock must remain perfectly intact, without any cracks visible to the naked eye in order to be compliant with standard specifications.
E.g. ICTA 3422
Impact resistance is expressed by the second digit: 4.
The ICTA 3422 sample is cooled to a temperature of -5°C and, after 2 hours, subjected to a 6 Joules energy shock test (1 x 2 Kg hammer placed 30 cm from the sample).
Resistance test at the minimum operating and installation temperature
1. During the impact resistance test, the mechanical resistance at the minimum temperatures required by the standard is also tested.
E.g. ICTA 3422
Resistance to minimum operating and installation temperature is expressed by the third digit: 2.
The impact test is performed on samples chilled to -5°C.
Resistance tests at maximum operating and installation temperatures
1. The sample is placed in a kiln at the temperature required by the standard for 4 hours.
2. After this time has elapsed, the sample is loaded for 24 hours with the weight specified by the standard whilst still inside the kiln.
3. After 24 hours, the load is removed and the internal diameter measured, using a special sliding gauge, which must not be less than the value declared by the manufacturerE.g. ICTA 3422
Resistance to maximum operating and installation temperature expressed by the fourth digit: 2. The ICTA 3422 sample is placed in a kiln at a temperature of 90°C for 4 hours and is then weighted with a load of 2 kg for 24 hours. After the test, the internal diameter must not be less than the minimum internal diameter indicated by the manufacturer.
Fire resistance test
This test is only performed on plastic channels, which are declared self-extinguishing, with a 1 kW flame.
1. The sample ICTA conduit is tested using a flame which can reach 700°C in 45 seconds.
2. The flame must be applied for a time that varies, depending on the thickness of the conduit wall (for example, for a 20 mm diameter, the application time is 20 seconds).
3. When this time has elapsed, the flame is removed: at this point, the conduit must not burn for more than 30 seconds and any drops must not ignite the tissue paper placed under the conduit.
Rigid conduits (fifth digit = 1)
Conduits with an outer diameter of 16, 20 and 25 mm, declared cold bend resistant by the manufacturer, have to be tested with a specific device: before starting the test, a steel cylindrical bender is inserted inside the conduit, to prevent it from collapsing during the bending. Conduits must be tested when cold, after being conditioned for at least two hours, at the minimum operating temperature required by the standard, and their bending radius must be at least 6 times their diameter.
After the test, carried out only once, the samples must not show any visible cracks.
Pliable/self-recovering conduits (fifth digit = 2/3)
Conduits must be tested with a specific device, without inserting a bender. Conduits must be tested when hot and their minimum bending radius must be 3 times their diameter. After the test, the samples must not show visible cracks and the difference between the original outer diameter and the post-test outer diameter should not exceed 10%.
Flexible conduits (fifth digit = 4)
The bending resistance test is not applicable.
Glow wire test
Glow Wire Test measures the self-extinguishment using a glowing wire.
This test is relevant for accessories, which can have two different resistance temperature: 850°C and 960°C.
During the test, a glowing wire, which reaches the temperature established by the standard, is positioned in contact with the accessory for a fixed time. After the wire has been removed, the accessory combustion has to finish.
Insulation resistance and dielectric strength
Pipe samples are soaked for a length of 1 m +/-10 mm in salted water, at the temperature of 23 (+/- 2)°C. A surface of approximately 100 mm has to be left outside the water level. Two electrodes are then positioned: one inside the pipe, one inside the tank.
Dielectric strenght test:
24 hours later, a growing tension from 1000 to 2000 V is applied to the electrodes. When the 2000 V tension is reached, it has to be maintained for 15 minutes.
The samples have an adequate dielectric strength if the security device does not intervene during the 15 minutes test.
Insulation resistance test:
A constant tension of 500 V is applied between the two electrodes, testing the insulation resistance after 60 seconds.
Pipe insulation resistance is adequate if it exceeds 100 MΩ.