BASEC A1706

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Flexishield Cable
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Developed for use in partitions and building voids

BS 8436 & IS 273 - Circuit Breakers

Flexishield cables are manufactured to BS 8436 & IS 273 standards, one of the main performance requirements within these standards is that the cable must fail safe if penetrated by a nail.

In order for the cable to meet this requirement Flexishield has been designed with a heavy duty aluminium tape bonded to the inside of the outer sheath, it is in contact with a bare full size tinned copper earth conductor, therefore if the cable was penetrated by a nail which hit the live phase conductor, the fault current path would follow the direction as illustrated below and trip the circuit MCB.

Diagram showing nail through cable

Within BS 8436 it outlines the test/overcurrent current requirements to operate a Type B MCB in relation to the cable size and the breaker ratings, this based on BS7671:2008 Fig 3A4 time/current curves:


For the IS 273 standard, it is defined slightly different as follows:

Proactive Device Rating (A) Test current values (A) for different circuit-breaker types
BS 88 Fuse Type B
circuit-breaker
Type C
circuit-breaker
Type D
circuit-breaker
16 85 80 160 320
20 130 100 200 400
32 220 160 320 640

In essence cables that meet these standards have to have the ability for the fault current flow path to withstand up to 160A to be able to operate a Type B MCB rated up to 32A, a Type C of 16A and a Type D of 6A rating, as per Figs 3A4, 3A5 and 3A6 in BS7671:2008

Flexishield has now been designed to withstand a 200A fault current, this allows circuits to be used with up to 40A Type B or a 20A Type C circuit breaker. This is witnessed on a regular basis by BASEC as part of the company's quality and product certification system.