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HD 602 Tests on gases evolved during the combustion of materials from cables : Determination of

degree of acidity (corrosivity) of gases by measuring pH and conductivity

1. HD 605 Electric cables: Additional test methodsScope

This section specifies requirements for and dimensions of single-core and multi-core polymeric insulated and polymeric sheathed halogen free cables with reduced fire propagation performance.

The maximum continuous operating temperature shall not exceed 90°C. The maximum temperature for short circuit conditions is 170°С for thermoplastic polymer compounds and 250°C for crosslinked polymer compounds.

This section covers the following classes of cables:

1. 2,3,4 and 5 core cables with copper or aluminium conductors and a concentric copper

conductor or a copper shield, if requested;

2. Single-core cables with a copper or aluminium conductor and a concentric copper conductor or a copper shield, if requested;

3. Auxiliary cables with copper or aluminium conductor and a concentric copper conductor or a copper shield, if requested.

2. Additional general requirements

The following general requirements shall be read in conjunction with those given in Part 1.

The marking has to be permanent and easily distinguishable, should different colours be used.

Concentric conductors need no marking.

The cores of cables with between one and five conductors shall be identified by colours in accordance with the following scheme:

The identification of a core having a reduced conductor cross-section area shall be: - green/yellow for cables with green/yellow core

The portions of the colours of green/yellow marked cores have to fulfill the following requirements:

On any 15mm long piece one of these colours may cover a minimum of 30% but not more than 70% of the core surface, while the other colour has to cover the remaining surface.

Each cable must have one of the following indications of origin:

1. An identification thread which is registered by the manufacturer;

2. A continuous marking with a trade mark which is registered by the

manufacturer;

3. A continuous marking with the manufacturer's name.

The indication of origin has to be legally protected.

The marking according to 2.2.1 can be done by:

1. Enclosing the identification thread(s) in the cable;

2. Printing on the sheath;

3. Convex or concave embossing on the sheath.

Each cable must have the following additional marking for improved performance in case of fire.

FRH - flame retardant²⁷, halogen-free²¹

The marking shall be repeated at regular intervals of not more than 550mm.

Unless otherwise specified the tests shall be made at ambient temperature of (25±10)°C.

The type test is the group of tests to which one or more samples (units) of an electric cable must be subjected. It is assumed that products of the same type behave in the same way. The type test is carried out on cables to prove that a certain type fulfils the necessary requirements in all characteristics. The type test is so constructed as to make its repetition unnecessary, providing that no alterations to materials or to the design which could affect the cable characteristics take place.

The sample test is the test carried out on a certain number of samples of the manufacturing lot of the same cable type.

The sample test is to be repeated at suitable intervals, so as to assure that the product fulfils the design requirements.

The routine test is the group of tests which each unit has to undergo according to the appropriate technical regulations for the cable type in question.

The routine test assesses whether the delivery length of the product fulfils the relevant requirements. Usually this test is carried out on each manufacturing length after it is finished or, in as far as possible, during manufacturing.

3. Cables with copper or aluminium conductors and optional copper concentric conductors or screens

   1. Code designation (under consideration by TC20)

See table 5.

0.6/1 kV

Copper or aluminium conductors are permissible. The conductors shall comply with HD 383. The copper conductors may be plain or tinned. A separating tape may be applied over the conductor.

The insulation shall be a thermoplastic halogen-free compound of Type IHN2 or a crosslinked halogen-free compound of Type IHN1 and shall comply with the requirements and tests specified in Table 1A. The insulation wall thickness shall comply with the value specified in Table 4. The minimum thickness at any place is the product of 0.9 multiplied by the specified value, minus 0.1mm and rounded to two places after the decimal point.

A covering element may be applied over the insulation. Insulation and sheath of single-core cables shall be separable.

The cores of cables with between two and five cores shall be stranded. A tape or a binder tape may be applied over the stranded cores.

The cores of multi-core cables with more than five conductors shall be stranded in concentric layers. A binding tape may be applied over the individual layers.

The core assembly of multi-core cables shall be completely covered by an easily removable inner covering which may, however, stick to the sheath.

It may consist either:

• of a tape bedding

• of an extruded bedding compound, or

• of a combination of the two.

Fillers for the interstices may be applied.

NOTE: The thickness of tape or extruded beddings need not be

checked by measurement.

3.3.4.2 Thickness

The rules for the recommended value of the thickness of the inner- covering are:

For cables with an inner covering consisting of tapes the recommended thickness should be:

0.3mm for a calculated diameter over the stranded cores up to and including 40mm; 0.5mm for diameters above 40mm.

For cables with extruded inner covering the related thickness should be calculated by the following formula:

S = 0.02 D + 0.6

S = wall thickness of the inner covering

D = Diameter over the stranded cores given by the construction

The concentric conductor or screen must consist of copper. This should be applied over the insulation of single-core cables or, if such exists, over its covering, and should be applied over the inner covering of multi-core cables.

A concentric conductor has to have the nominal cross section of the phase conductor or, in the case of a reduced cross section, the nominal cross section which is assigned to the phase conductors given in Table 3.

The nominal cross section which is declared for concentric conductors is always based on the material of the phase conductors.

As far as aluminium phase conductors are concerned, the d.c. conductor resistance of the concentric conductor may not be more than that of an aluminium phase conductor of the declared nominal cross section.

A concentric conductor or screen made of wires may consist of plain or tinned copper wires. These have to be applied uniformly distributed over the circumference. The mean calculated distance between single wires may not be more than 4mm. The measured distance between any single wires may not exceed 8mm.

If a concentric conductor or screen consists of copper tape, this should overlap. If a concentric conductor or screen consists of several copper tapes, applied one upon another, then the tapes should overlap or be applied in a close helix.

Over concentric conductors or screens of copper wires one or two copper binding tapes have to be applied. The thickness of the tapes has to be in the range 0.1 to 0.3mm.

The measured d.c. resistance of each binding tape in the stretched position shall not exceed:

• 36.0 Q/km in the case of cables with a diameter up to 15mm below the

screen

• 18.1 Q/km in the case of cables with a diameter of more than 15mm below

the screen.

The measured d.c. resistance of the screen may not exceed the nominal value given in HD 383.

A covering or a tape of halogen-free material may be applied over the concentric conductor or screen.

The sheath shall consist of a cross-linked or the thermoplastic polyolefin compound of type MHN1 or MHN2 and shall comply with the requirements and tests specified in Table 1B.

As regards cables without concentric conductor or screen the sheath shall be applied over the inner covering of multi-core cables, or over the insulation or, if such exists, over the covering of the insulation.

In the case of single-core cables, insulation and sheath shall be easily separable without damaging the insulation.

As regards cables with concentric conductor or screen the sheath shall be applied over these elements or, if such exists, over the covering of the concentric conductor or screen.

The colour of the sheath shall be black.

The nominal wall thickness in millimetres of the sheath (S) shall be calculated from the following formula:

S = 0.03 D + 1.1, where S is the nominal wall thickness of the sheath and D is the diameter under the sheath given by the construction of the cable.

The nominal value of the sheath thickness shall not be less than 1.8 mm.

For cables with concentric conductors or screen the minimum value of the sheath is the product of 0.85 multiplied by the nominal wall thickness, minus 0.3mm.

For cables without concentric conductor or screen the minimum value of the sheath is the product of 0.85 multiplied by the nominal wall thickness, minus 0.1mm.

The thickness of the sheath at any place shall not be less than the minimum value.

4. Tests

Compliance with the requirements of clause 3 shall be checked by inspection and by the tests specified in Tables 2 to 4.

Ageing temperature (120±2)°C if the nominal value of the wall thickness <0.5mm

The test only has to be carried out if it is required in the relevant regulations

The test duration is 4h if the nominal cross section of the conductor is 535mm²; if the nominal cross section is >35mm², the duration is 6h.

Table 1A

Requirements and tests for the insulation compounds

to (21 (3)

Table 1A

Requirements and tests for the insulation compounds (concluded)