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Cross sectional area of a protective conductors

MS01
Can someone give me a some advice on if we have a earth electrode system made up of the structural rebar when using the adiabatic equation to size of the bonding conductor comes out at 300mm. MY questions is does each bond need to be this size or can it be made up via a series of smaller bonds that are equal or exceed the 300mm requirement? My opinion is each bond needs to be this size to deal with the fault current as the direction it will flow is unknown. What are peoples thoughts? I cannot see anything in the regs on this.

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    A bit more detail it’s a new build development with a 5MVA supply (2x2.5MVA TX's) so the fault level by tweaking the impedance is just below 100kA. The site is cold but as its HV metered soil resistivity test have been carried and structural rebar and a number of piles. The rebar is in line with BS50522 and is 50mm² and incased in concrete. From the Rebar there are a number of bonds to earthing bars around the development.

    Now the fault level used by the earthing specialist is 1.77kA given by the DNO, however my concern is a fault on the LV side where the fault current could be as high as 100kA.  

    EPR etc isn’t an issue as its global earthing system, but the question is should the bonds to the rebar be cable of taking the high fault current?
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    A bit more detail it’s a new build development with a 5MVA supply (2x2.5MVA TX's) so the fault level by tweaking the impedance is just below 100kA. The site is cold but as its HV metered soil resistivity test have been carried and structural rebar and a number of piles. The rebar is in line with BS50522 and is 50mm² and incased in concrete. From the Rebar there are a number of bonds to earthing bars around the development.

    Now the fault level used by the earthing specialist is 1.77kA given by the DNO, however my concern is a fault on the LV side where the fault current could be as high as 100kA.  

    EPR etc isn’t an issue as its global earthing system, but the question is should the bonds to the rebar be cable of taking the high fault current?
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