Table 4 - Compression force
|
Classification |
Conduits |
Compression force Tolerance % N |
|
1 |
Very light |
125 |
|
2 |
Light |
320 |
|
3 |
Medium |
750 |
|
4 |
Heavy |
1250 |
|
5 |
Very heavy |
4000 |
The difference between the initial outside diameter and the diameter of the flattened sample shall not exceed 25 % of the initial outside diameter measured before the test.
The force and the intermediate piece are then removed and, (60 ± 2) s after removal, the outside diameter of the samples, where they have flattened, shall be measured again.
The difference between the initial diameter and the diameter of the flattened samples shall not exceed 10 % of the outside diameter, measured before the test.
After the test, the samples shall show no cracks visible to normal or corrected vision without additional magnification.
Impact test
Twelve samples of conduit each (200 ± 5) mm in length, or twelve conduit fittings are subjected to an impact test by means of the apparatus shown in Figure 2.
Before the test, the samples are assembled with all the components as for normal use, including conduits required for conducting of the test.
NOTE Conduit fittings are not required when testing conduits.Parts, which are not accessible when mounted in normal use, and small conduit fittings whose maximum dimension is less than 20 mm, are not subjected to this test.
The test apparatus, together with the samples, shall be placed in a refrigerator, the temperature within which shall be maintained at the declared temperature as given in Table 1 with a tolerance of ±2 °С.
When the samples have attained the temperature specified, or after 2 h, whichever is the longer period, each sample shall be placed in position on the steel base as shown in Figure 2. The hammer shall be allowed to fall once on each sample. The mass of the hammer and the fall height shall be as given in Table 5.
The test shall be made on the weakest part of the conduit fitting, except that it shall not be applied to within 5 mm of any conduit entry. Samples of conduit are tested at the centre of their length.
Table 5 - Impact test values
|
Classification |
Conduit and fittings |
Mass of hammer Tolerance +q % kg |
Fall height Tolerance ± 1 % mm |
|
1 |
Very light |
0,5 |
100 |
|
2 |
Light |
1,0 |
100 |
|
3 |
Medium |
2,0 |
100 |
|
4 |
Heavy |
2,0 |
300 |
|
5 |
Very heavy |
6,8 |
300 |
After the test, when samples have attained (20 ± 5) °С, it shall be possible to pass the appropriate gauge specified in the relevant particular requirements (Parts 21, 22, 23, etc.) through the conduit, under its own weight and without any initial speed, with the sample in the vertical position. There shall be no sign of disintegration nor shall there be any crack visible to normal or corrected vision without magnification.
At least nine of the twelve samples shall pass the test.
Bending test
The test is specified in 61386.
the relevant particular requirements (Parts 21,
22, 23, etc.) of IEC
Flexing test
The test is specified in 61386.
the relevant particular requirements (Parts 21,
22, 23, etc.) of IEC
C
23, etc.) of IEC
ollapse testThe test is specified in the relevant particular requirements (Parts 21, 22, 61386.
Tensile test
Conduit systems declaring tensile strength shall be tested as follows:
A sample of conduit and two conduit fittings or terminating conduit fittings are assembled in accordance with the manufacturer’s instructions so that the length of the conduit between the fittings is at least 200 mm. Where this is impractical, the test shall be carried out on two samples of conduits and a conduit fitting. The assembly is subjected to a uniformly increasing tensile force reaching the value given in Table 6, at (23 + 2) °С, in (30 ± 3) s. This tensile force is then maintained for 2 min ± 10 s.
Where elongation occurs, the manufacturer shall be responsible for providing guidelines to assist the safe installation of the conduit system.
For conduit systems where tensile strength is not declared, the tensile strength of the joint shall meet the requirements of the relevant tests of the appropriate Part 2.
After the test, the conduit fittings or terminating conduit fittings shall remain properly assembled to the conduit, and there shall be no damage visible to normal or corrected vision without magnification.
Table 6 - Tensile force
|
Classification |
Conduit and fittings |
Tensile force Tolerance +o % N |
|
1 |
Very light |
100 |
|
2 |
Light |
250 |
|
3 |
Medium |
500 |
|
4 |
Heavy |
1000 |
|
5 |
Very heavy |
2500 |
Suspended load test
The conduit fitting, declared by the manufacturer to be suitable for suspended loads, is secured to a rigid structure using a method provided by the manufacturer, with the suspension means pointing downwards.
A load, with a time duration in accordance with Table 7, is suspended by the means provided, and installed in accordance with the manufacturer’s instructions.
The fitting shall be deemed to have passed if at the end of the test, there are no cracks visible to normal or corrected vision without magnification, and there is no deformation of the conduit fitting impairing its normal use.
For поп-metallic and composite conduit fittings, the test shall be carried out in a heating cabinet, the temperature within which is maintained at the declared maximum temperature given in Table 2 with a tolerance of ±2 °С.
Table 7 - Suspended load
|
Classification |
Fittings |
Load Tolerance +Q % N |
Duration Tolerance 0min h |
|
1 |
Very light |
20 |
48 |
|
2 |
Light |
30 |
48 |
|
3 |
Medium |
150 |
48 |
|
4 |
Heavy |
450 |
48 |
|
5 |
Very heavy |
850 |
48 |
Electrical properties
Electrical requirements
Conduit systems declaring electrical continuity characteristics shall be checked by the test in 11.2 immediately after the test in 14.2.
NOTE Conduit systems, in some circumstances, may be used in total or in part as a protective conductor in an electrical installation. In that event, the system will be tested after final installation to confirm its suitability for that purpose, in accordance with the installation rules.
Conduit systems of metal or composite materials shall be so constructed that accessible metal parts can be bonded to earth.
Compliance is checked by inspection.
Accessible conductive parts of the metal or composite conduit system, which may become live in the event of a fault, shall be effectively earthed.
Compliance is checked by the test in 11.2.
Conduit systems of non-metallic or composite materials, where declared, shall have an adequate electrical insulating strength and insulating resistance.
Compliance is checked by the test in 11.3.
Bonding test
An arrangement of conduit and conduit fittings, consisting of 10 pieces of conduit, shall be coupled together, in accordance with the manufacturer's instructions and Figure 3, by means of conduit fittings representing, in approximately equal numbers, each type of fitting. The fittings shall be spaced between 100 mm and 150 mm apart. A current of 25 A, having a frequency of 50 Hz to 60 Hz derived from an a.c. source having a no-load voltage not exceeding 12 V, is passed through the assembly for (60 + 2) s. The voltage drop is then measured and the resistance calculated from the current and that voltage drop.
The resistance shall not exceed 0,1 £2.
If the numbers of different types of fittings cannot all be accommodated in a single test, the test described above shall be repeated until all such different types of fittings have been tested.
Where special devices are required for the coupling of conduit and conduit fittings, they shall be sufficient to remove the protective coating from the conduit, or the protective finish shall be removed in accordance with the manufacturer's instructions.
Dielectric strength and insulation resistance
Conduits
Samples of conduit are immersed over a length of 1 m ± 10 mm in accordance with Figure 4 or Figure 5 in a salt water solution at (23 ± 2) °С, with a length of 100 mm kept above the level of the solution.
Rigid conduit samples are to be supplied by the manufacturer complete with one end sealed with an appropriate insulating material with high electrical insulation, for example silicone elastomer; see Figure 4.
Pliable and flexible conduit samples are bent into a "U" shape and then immersed; see Figure 5.
The salt water solution is made by completely dissolving 1 g/l of sodium chloride.
The salt water solution is poured into the open end of the conduit to match the external level. An electrode is placed inside the conduit and another placed into the tank.
After 24 h ± 15 min, a voltage is applied across the two electrodes, gradually being increased from 1 000 V to 2 000 V of substantially sine wave form and having a frequency of 50 Hz to 60 Hz. Having reached 2 000 V, the voltage is maintained for a period of 15 min s.
The high-voltage transformer used for the test is so designed that, when the output terminals are short-circuited after the output voltage has been adjusted to the appropriate test voltage, the output current is of at least 200 mA. The overcurrent relay shall not trip when the output current is less than 100 mA. Care is taken that the r.m.s. value of the test voltage applied is measured within ±3 %.
The samples shall be considered to have adequate electrical insulating strength if a 100 mA trip device, incorporated into the circuit, does not trip during the 15 min test.
Immediately after the test in 11.3.1.2, the same samples shall be subjected to an electrical insulation resistance test. A d.c. voltage of 500 V shall be applied across the two electrodes.
After (60 ± 2) s from the application of the voltage, the insulation resistance between the electrodes shall be obtained. Conduits shall be considered to have adequate electrical insulation resistance if the measured resistance is greater than 100 M£2.
Conduit fittings
Samples of conduit fittings shall be immersed for 24 h ± 15 min, in water at (23 ± 2) °С, and then thoroughly dried at room temperature.
Conduit fitting samples shall be assembled in accordance with the manufacturer's instructions with a length of conduit not less than 100 mm. All other open ends are sealed with an appropriate insulating material. The inside of the fitting is filled with lead spheres of a diameter between 1,0 mm and 1,5 mm, and an electrode is inserted into the lead shot via the conduit.
An outer electrode of aluminium foil is wrapped around the outside of the fitting and compressed so that it follows the outer contour of the fitting as closely as possible.
Conduit fitting samples shall be tested in accordance with 11.3.1.2 within 1 h of removal from the water.
Immediately after the test in 11.3.2.3, the same samples are subjected to an electrical insulation resistance test. A d.c. voltage of 500 V is applied across the two electrodes.
After (60 ±2) s from the application of the voltage, the insulation resistance between the electrodes Is obtained. Fittings are considered to have adequate electrical insulation resistance if the resistance is greater than 5 MT2.
Thermal properties
Non-metallic and composite conduits shall have adequate resistance to heat.
Compliance is checked by the test in 12.2. and verified with 12.3 .
The load for the heating test shall be the same classification as the declared compression classification.
Samples of conduit, each (100 ± 5) mm long, together with the test apparatus as shown in Figure 8, shall be kept for 4 h ± 5 min in a heating cabinet at the declared temperature given in Table 2, with a tolerance of ±2 °С.
After this period, each sample is loaded for 24 h ± 15 min in an apparatus, as shown in Figure 8, with an appropriate mass applied through a steel rod (6,0 ± 0,1) mm in diameter, disposed at right angles to the axis of the conduit.
The sample is subjected to a total mass, including the mass of the rod, as shown in Table 8, placed in the middle of the sample.
The sample, under load, shall then be allowed to cool to room temperature.
Table 8 - Load for heating test
|
Classification to compression according to 6.1.1 |
Conduits |
Mass Tolerance+Q % kg |
|
1 |
Very light |
0,5 |
|
2 |
Light |
1,0 |
|
3 |
Medium |
2,0 |
|
4 |
Heavy |
4,0 |
|
5 |
Very heavy |
8,0 |
The load is then removed, and immediately after its removal, it shall be possible to pass the appropriate gauge, specified In the relevant Part 2, through the conduit, under its own weight and without any initial speed, with the sample in the vertical position.
Fire hazard
Reaction to fire
Initiation of fire
Not applicable.
NOTE Conduit systems are not in direct contact with live parts.
Contribution to fire
Under consideration.
Spread of fire
Non-flame propagating conduit systems shall have adequate resistance to flame propagation.
Compliance of non-metallic and composite conduit fittings is checked by using the glow-wire test in IEC 60695-2-11.
The glow wire shall be applied once to each sample in the most unfavourable position for its intended use (with the surface tested In a vertical position) at a temperature of 750 °С.
The sample is deemed to have passed this test if there is no visible flame or sustained glowing, or if flames or glowing extinguish within 30 s of the removal of the glow wire.
Compliance of non-metallic and composite conduits is checked by applying a 1 kW flame, as specified in IEC 60695-11-2.
A sample of length (675 + 10) mm is mounted vertically in a rectangular metal enclosure with one open face, as shown in Figure 6, in an area substantially free of draughts.
The general arrangement is shown in Figure 7.
Mounting is by means of two metal clamps approximately 25 mm wide, spaced (550 ±10) mm apart and approximately equidistant from the ends of the sample.
A steel rod of (2,0 ± 0,1) mm for sizes up to 12 mm, (6,0 ±0,1) mm for sizes 16 mm to 25 mm and (16,0 ±0,1) mm for conduits with diameters 32 mm and above is passed through the sample. It is rigidly and independently mounted and clamped at the upper end to maintain the sample in a straight and vertical position. The means of mounting is such as not to obstruct drops from falling onto the tissue paper.
A suitable piece of white pine wood board, approximately 10 mm thick, covered with a single layer of white tissue paper, is positioned on the lower surface of the enclosure.
The assembly of sample, rod and clamping apparatus is mounted vertically in the centre of the enclosure, the upper extremity of the lower clamp being (500 ±10) mm above the internal lower surface of the enclosure.
The burner is supported so that its axis is at an angle of (45 ±2) ° to the vertical.
The flame is applied to the sample so that the distance from the top of the burner tube to the sample, measured along the axis of the flame, is (100 ±10) mm, and the axis of the flame intersects with the surface of the sample at a point (100 ± 5) mm from the upper extremity of the lower clamp, and so that the axis of the flame interacts with the axis of the sample.
The flame is applied to the samples for the period given in Table 9, and is then removed. During the application of the flame, it shall not be moved, except to remove it at the end of the test period.
The determination of material thickness of plain conduit, corrugated conduit and combined plain conduit and corrugated conduit is given in Annex B. All three samples are measured and the mean material thickness is calculated for each sample. The highest mean value is used to determine the flame application time from Table 9.
Table 9 - Times of exposure of the sample to the flame
|
Mean material thickness mm |
Flame application time s |
|
|
Over |
Up to |
Tolerance +q s |
|
- |
0,5 |
15 |
|
0,5 |
1,0 |
20 |
|
1,0 |
1,5 |
25 |
|
1,5 |
2,0 |
35 |
|
2,0 |
2,5 |
45 |
|
2,5 |
3,0 |
55 |
|
3,0 |
3,5 |
65 |
|
3,5 |
4,0 |
75 |
|
4,0 |
4,5 |
85 |
|
4,5 |
5,0 |
130 |
|
5,0 |
5,5 |
200 |
|
5,5 |
6,0 |
300 |
|
6,0 |
- |
500 |
After the conclusion of the test, and after any burning of the sample has ceased, the surface of the sample is wiped clean by rubbing with a piece of cloth soaked with water.
All three samples shall pass the test.
The sample is deemed to have passed the test if it does not ignite.
The sample is deemed to have passed the test if it does ignite but all of the following are met:
flaming or glowing of the sample is extinguished within 30 s after removal of the test flame,
the tissue paper does not ignite,
after extinction of the flaming or glowing of the sample, there is no evidence of burning or charring within 50 mm of the lower extremity of the upper clamp.
