BS 7629-1:2015+A1:2019 - Page 2

Electric cables. Specification for 300/500 V fire resistant, screened, fixed installation cables having low emission of smoke and corrosive gases when affected by fire. Multicore cables | Status: Confirmed, Current

1 Scope This British Standard 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 which measure resistance to fire with mechanical impact and water spray (Categories: Standard 30, Standard 60 and Enhanced 120).

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.

It is applicable to 2‑core, 3‑core and 4‑core circular cables with an uninsulated full-size circuit protective conductor (CPC), and 7‑core, 12‑core and 19‑core 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 short‑circuit conductor temperature of 250 °C (for a maximum period of 5 s).

NOTE 2 Annex A gives recommendations for the selection, installation and operation of cables, Annex B gives the method of test for continuity of tinned coating of wires, Annex C gives the method of test for voltage withstand, Annex D gives the method of test for bending characteristics, Annex E gives the method of test for resistance to impact, Annex F gives the method of test for shrinkage of sheath and Annex G gives notes on type tests.