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BS 8436 Cable

Jonesy
Hi all I am new to the Forum.


I have a question regarding BS 8436 Compliant Cables. I am aware iof the requirement to protect circuits wired in BS 8436 Cables with "B" Type devices etc due to the requirement to limit fault current in the event of the cable being penetrated by a nail or a screw. However, what if you install the cable clipped direct to the surface and on Cable Tray or basket where the risk of accidental penetration is very low, would it them be acceptable to protect the circuit with "C" Type devices?


I have hunted high and low on the internet for an solution but have failed to find a definitive answer.
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    Keith Jones:

    . . .  Batt cables state that their cable can withstand a fault current of up to 200 amp which according to Fig 3A5 BS7671 is the current required to operate a 20 AMP Type C MCB  0.1 TO 5 Seconds. . . 




    Yes, but the actual fault current will be limited by the impedance of the supply. You may find that significantly more current flows - if it is a few thousand amps, your cable may not survive. As Andy has already said, the only thing you can limit, is the energy let through, by choosing a fast enough mcb. 


    Regards,


    Alan. 

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  • 0

    Keith Jones:

    . . .  Batt cables state that their cable can withstand a fault current of up to 200 amp which according to Fig 3A5 BS7671 is the current required to operate a 20 AMP Type C MCB  0.1 TO 5 Seconds. . . 




    Yes, but the actual fault current will be limited by the impedance of the supply. You may find that significantly more current flows - if it is a few thousand amps, your cable may not survive. As Andy has already said, the only thing you can limit, is the energy let through, by choosing a fast enough mcb. 


    Regards,


    Alan. 

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