SCOPE: British Standard BS 7629 specifies requirements and test methods for the construction and performance of cables which:
- have thermosetting insulation and a rated voltage of 300/500 V;
- provide resistance to fire (circuit integrity), including with mechanical shock and with water, as measured by performance in a standard test or tests;
- emit limited amounts of smoke and corrosive gases when burned as measured by a standard test; and
- are primarily intended for use in emergency lighting, fire detection and fire alarm system circuits.
The circuit integrity performance under fire conditions is assessed on the basis of tests that measure resistance to fire with mechanical impact and water spray (Categories: Standard 30, Standard 60 and Enhanced 120).
It is applicable to 2 core, 3 core and 4core circular cables with an uninsulated full-size circuit protective conductor (CPC), and 7core, 12core and 19core circular multicore auxiliary cables with an uninsulated drain wire of not less than 0.5 mm2. All cables contain a metallic layer, which provides electrostatic screening.
The cables are suitable for operation at a maximum sustained conductor temperature of 70 °C and for a maximum shortcircuit conductor temperature of 250 °C (for a maximum period of 5 s).
NOTE 1 BS 5266-1 and BS 5839-1 give recommendations and guidance on the factors to be taken into account in the planning, design, installation, commissioning and maintenance of emergency lighting, fire detection and fire alarm systems for buildings, respectively.
NOTE 2 Annex A of the Standard gives recommendations for the selection, installation and operation of cables,