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recording conductor sizes on schedules

psychicwarrior

Hello all 

what do ‘you’ record on EIC and/or EICR if a circuit has smaller conductor sizes downstream of its run (where origin fuse is adequately protecting)  ?

 

Regards

Habs

 

  • 0

    Two questions (assuming the OCPD can't provide overload protection for the smaller csa conductors):

    1. Can overload current protection be omitted for the smaller csa conductors?

    2. Does the overcurrent protective device provide fault current protection for the smaller csa?

    If the answer to BOTH of those questions is “YES” then there is, most likely, no issue.
    If the answer to EITHER of those is “NO”, it's probably a C3 or a C2 depending on the circumstances.

  • 0

    I think the Warrior was asking about the csa size of the conductors to be recorded where they differ along the length of a circuit. The key thing, of course, is to establish that appropriate protection is in place and voltage drop is not impaired. 
    I use my own templates base on MS Word so it is easy for me to slip an asterisk beside the cable size (I refer to the one leaving the CPD no matter how short) and then comment at the foot of the schedule to indicate whatever arrangement follows.
     

  • 0

    Take, for example, a kitchen radial in 4 sqmm but with switched spurs to under-the-counter single sockets for specified appliances. It would be a waste of copper to make them in 4 sqmm - could even be 1.5 sqmm. I would specify 4 sqmm for the circuit but add a comment in the “remarks” box; e.g. “spurs to named sockets in 2.5 sqmm T&E”.

  • 0

    Yes I was referring to reduced CSA downstream (still adequately protected etc) .

     

    I have always added the size present at the cpd and ‘remarked’ if needed any downstream variation. 

     

    It was one of those moments of curiosity and as has been mentioned, whether some use bespoke forms and so on.

     

    Thank you.

  • 0

    If it`s a ring (with or without spurs) we`d always put 2.5 on a 2.5 ring rather than 5.0? Similarly with reduced cpc which is usually 1.5

    Therefore the csa of conductor(s) leaving the opd

  • 0

    Just worth noting. It would only be 5mm² equivalent at the equidistant point from the termination in the CSU. Each “arm” of the ring being equal resistance at that position. Anywhere else on the ring will carry current in proportion to the resistance of each “arm” following the usual formula for resistors in parallel. Conversely a radial circuit fed by two 2.5mm² cables in parallel is equivalent to 5mm² surface area as the two conductors are always of equal length.

    Cheers Andy

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