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Combined LV earth systems

Stuz

Hello all,

Working on a project where we have 2x 1000kVA transformers directly connected to a separate main panel each. Supplies are TNS. Panels are next to each other. 

Consultant wants a combined earth bar with both earth connections connecting. 

Is there not a risk of circulating neutral earth currents? Or is this required? I've always kept the earth systems (LV) separate.

Thoughts gratefully received. 

S

  • 0

    SImultaneously accessible exposed-conductive-parts MUST be connected to the same earthing system for safety (Regulation 411.3.1.1).

    THe question, though, is whether the supplies are ever paralleled (multi-source). If they are, then there must only be one N-PE connection, not two. See Regulation 444.4.6 (Fig 44.9 and Fig 4410) in BS 7671.

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