Out with the old, in with the new
Dr. Jeremy Hodge (pictured), Chief Executive of the British Approvals Service for Cables (BASEC) reports on the withdrawal of BS 6346 and the development of 'BS 8573 Electric cables - Thermosetting insulated, non-armoured cables with a voltage of 600/1 000V, for fixed installations, having low emissions of smoke and corrosive when affected by fire’, which is currently in preparation with the British Standards Institution (BSI).
For nearly 40 years, BASEC has been a recognised sign of assurance of independent cable testing and approval. Its product certification services cover electrical cables, data and signal cables and ancillary products and all products are rigorously tested to meet necessary and appropriate British, European and international standards through detailed examination of manufacturers' production processes and controls.
For some time there has been specifier demand for a low smoke halogen free non-armoured power cable for use within buildings, where the armour protection afforded by traditional armoured cables is not fully justified. BASEC has therefore been pushing for a new standard to be developed for non-armoured XLPE insulated cables with a low smoke sheath, similar to PVC-sheathed cables made to a current standard, BS 7889.
A new standard ‘BS 8573 The use of such cables is predicted to offer specifiers potential savings of weight, space and cost. These power cables could be used in places where, in case of fire damage, loss of human life and material assets must be prevented, but where mechanical protection is less important or provided by other means.
The same cable type with a PVC sheath is currently on the market, to BS 7889. This is a non-armoured XLPE insulated PVC sheathed cable commonly used within buildings for power distribution, for which certification is available from BASEC. Certification is also offered for a branch cable system for power distribution in multi-storey buildings, using this type of cable, and this scheme will be extended to use the low smoke cable version once the standard is published.
The BS 7889 standard will remain unchanged, although cables with PVC sheaths are becoming less commonly used in environments such as shopping centres, schools, hospitals and other public buildings where the preference is changing towards predominantly low smoke cables being used.
Other PVC-containing standards are continuing to decline in use. In particular, standard BS 6346 – PVC insulated, PVC sheathed armoured cables for voltages of 600/1000 V and 1900/3300 V - has recently been withdrawn without a replacement. BASEC will continue to certify cables to BS 6346, as there remains market demand in several territories. The modern alternative to PVC insulation is cross linked polyethylene (XLPE), although PVC sheathing remains widely used.
BASEC also offers certification to the IEC standard IEC 60502-1 for low voltage power distribution cables. This standard permits many options of construction, including armoured or unarmoured, PVC or low smoke materials, so buyers should be careful to specify exactly what cable they want when using this standard.
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