Introduction
It is common to see bluesheathed flexible cables, sometimes referred to as "Arctic" cable, used on temporary low-voltage installations, such as construction sites, fairgrounds and musical events. In addition to blue, this type of cable is available in many different colours, such as yellow and orange and some cables even have the word ARCTIC embossed throughout the length. Not all cables are suitable for all applications. It is, therefore, important to establish the suitability of the cable in question prior to selection by referencing the standard to which the cable is manufactured. Two standards for flexible cable will be considered here - BS 7919 and BS 6500.
Cables to BS 7919
Electric cables — Flexible cables rated up to 450/750 V, for use with appliances and equipment intended for industrial and similar environments
Ordinary duty low temperature PVC insulated and sheath 300/500 V flexible cable, manufactured to BS 7919 Table 44 (not harmonised), commonly referred to as 3183A (Arctic Grade Flex), was specifically designed and, hence, included in the British Standard, for use at 110 V a.c. from centre tapped transformers (55 V - 0 - 55 V). The cable is suitable for installation and handling down to a temperature of -25°C, e.g. suitable for construction site installations and is often seen in use on temporary road works for supplies to traffic lights; Table 7B from BS 7450, refers. Note that cables to BS 7919 Table 44 have not been harmonised to European HDs. This is because the use of 110 V a.c. supplies from centre tapped transformers (55 V - 0 - 55 V) is a UK only practice and is not recognised or practised elsewhere.
BS 6500
Electric cables - Flexible cords rated up to 300/500 V, for use with appliances and equipment
intended for domestic, office and similar environments
Ordinary duty PVC insulated and sheath 300/500 V flexible cable to BS 6500, commonly
referred to as 3183Y (harmonised number H05VVF), is suitable for use at 230 V a.c. The cable is suitable for installation and handling down to a temperature of +5°C.
To view the full article (including Tables) from the IET's Wiring Matters Winter 2009, click on the attachment below...