BS 6081:1989 download.British Standard Specification for Terminations for mineral-insulated cables.
1 Scope
BS 6081 specifies requirements for terminations for use with mineral-insulated cables complying with
BS 6207.
NOTE. The titles of the publications referred to in BS 6081 are listed on the inside back cover
2 Definitions
For the purposes of BS 6081 the definitions given in BS 4727 : Part 2 : Group 08 apply, together with the following.
2.1 termination. A complete end fitting for a mineral- insulated cable, normally comprising a seal and a gland or a composite sealing and glanding device, but excluding any locknut, bush, associated unction box or accessory.
2.2 seal. The part of a termination designed to seal the end of the cable against entry of moisture and to insulate the conductor(s) beyond the point where the mineral insulant is terminated.
NOTE. It may or may not be used to ensure Circuit protection depending upon the type of construction and material used.
2.3 gland. The part of a termination designed to secure the cable into a cable entry.
NOTE. It my or may not be used to ensure circuit protection depending upon the type of construction and material used.
3 Marking
3.1 Marking of packages
Packages in which terminations or parts of terminations are supplied shall be marked wth the following particulars:
(a) the number of BS 6081,
i.e. BS6081 : 1989;
(b) a means of identifying the manufacturer or supplier;
(c) the maximum operating temperature of the seals, where applicable;
(d) cable size and voltage rating, where applicable.
3.2 Marking of seals
Where practicable, sealing pots or enclosures shall be marked with the cable size or some other means of identifying the cable or cables with which they are to be used.
3.3 Marking of glands
Where practicable, glands shall be marked with the cable size or some other means of identifying the cable or cables with which they are to be used.
NOTE. In the case of terminations or parts of terminations for use in potentially e’plos.ve atmospheres, additional markings may be required on the components andios packaging (see BS 5501).
4 Construction
4.1 Seals
4.1.1 Seals shall consist of an insulating, moistureresistant sealing material, if necessary contained within a sealing pot or other enclosure made from metallic and/or non-metallic materials for securing onto the end of the cable, and insulating material for the conductor tails.
4.1.2 If a copper protective conductor is provided for the seals it shall comply with the appropriate requirements of BS 6360 and its size shall be in accordance with the appropriate part of the lEE Regulations for Electrical Installations.
NOTE. The protective conductor may be connected to a metallic sealing pot or enclosure by any suitable method (e.g. welding. brazing, crimping or soldering), or it may be connected to some other form of metallic attachment (e.g. a clip or clamp) which can be used directly on the cable sheath.
4.1.3 The sealing material shall be such that the completed seal shall be capable of meeting the electrical test requirements specified in clause 5.
4.1.4 Conductor insulating material shall have a specified maximum operating temperature not less than the maximum operating temperature of the seal specified by the manufacturer.
4.2 Glands
4.2.1 Glands shall be manufactured from metallic and/or non—metallic materials.
4.2.2 Gland entry threads shall have a thread form in accordance with BS 6053, but other forms complying with national or international standards (e.g. DIN 40 430, ANSI/ASME B 1.20.1) are permissible provided the glands comply with all the other requirements of this standard.
4.2.3 The length of gland entry threads shall be not less than 8 mm for threads with major diameter of 32 mm or less and 10 mm for all other threads.
4.2.4 Glands for use in potentially explosive atmospheres shall, in addition to complying with this standard, also satisfy the appropriate requirements of BS 5501.
5 Type tests
5.1 General
The tests specified in BS 6081 are type tests intended to be performed prior to commercial supply of a termination, or part thereof, to demonstrate satisfactory design and material characteristics. Once satisfactory performance has been demonstrated these tests need not be repeated unless a change is made to either the design or material used which would affect the performance.
Unless otherwise specified, the tests shall be carried out at an ambient temperature of 20 ± 10 °C. The test voltage shall be either a.c. of appoximately sinusoidal waveform with a frequency in the range 49 Hz to 61 Hz, or d.c. equal to the peak value of the voltage and shall be applied gradually. Different samples shall be selected for the electrical tests and mechanical tests.
5.2 Seals
5.2.1 Voltage rest When tested in accordance with A.1 and A.2.1. samples shall withstand the following voltage without electrical breakdown:
500 V rated cable 1500 V r.m.s.
750 V rated cable 2500 V r.m.s.
5.2.2 Insulation resistance rest. When measured in accordance with A.1 and A.2.2, the insulated resistance shall be not less than 100 M!2.
5.2.3 Electrical continuity rest. When seals incorporating a protective conductor are tested in accordance with A.1 and A.2.3, the potential difference between the protective conductor attachment and the adjacent cable sheath shall not exceed 10 mV.
5.2.4 Minimum operating temperature rest. When tested at elevated temperature, in accordance with A.1 and A.2.4,samples shall have an insulation resistance of not less than 10 M!2 and shall withstand, without breakdown, a voltage equal to the rated voltage of the cable.
5.2.5 Temperature cycle test. When tested in accordance with A.1 and A.2.5, samples shall have an insulation resistance of not less than 100 M!2 and shall withstand, without breakdown, a voltage equal to the rated voltage of the cable.
5.2.6 Tensile test. Seal assemblies which are intended to be used as a means of attachment to supporting structure or enclosures shall, when tested in accordance with A.2.6, withstand the appropriate proof load (see table 1) without showing splits or cradcs or movement relative to the cable.
5.3 Glands
5.3.1 Electrical continuity tes. When glands which are intended to provide circuit protection are tested in accordance with A.1 and A.3.1, the potential difference between the gland and the adjacent cable sheath shall not exceed 10 mV.
5.3.2 Tensile test. Glands, when tested in accordance with A.3.2, shall withstand the appropriate proof load (see table 2) without showing splits or cracks or movement relative to the cable.