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Student & Learning Zone - City & Guilds
What fault can turn a TT into a TNCS and disable the RCD?
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<blockquote data-quote="sparkytim" data-source="post: 263923" data-attributes="member: 8627"><p>Not wanting to upset ANYONE, but I agree, NO system ia 100% safe, and this situation goes to show that includes TT.</p><p></p><p>In defence the Zs would have been low enough to Trip the MCB, but not before a sizable fault current would have travelled its route down the 1mm and back, (don't think it would pass an Adiabatic calculation)</p><p></p><p>I have found like You and many others I suspect, that N-E faults are common, they can sit for years on 3036 protected circuits with no effect,</p><p></p><p>So the Moral of the story is ; Test, Test and Test again, no way can you bang in a new CU and hope all is Ok, RCDs can be outwitted!.</p></blockquote><p></p>
[QUOTE="sparkytim, post: 263923, member: 8627"] Not wanting to upset ANYONE, but I agree, NO system ia 100% safe, and this situation goes to show that includes TT. In defence the Zs would have been low enough to Trip the MCB, but not before a sizable fault current would have travelled its route down the 1mm and back, (don't think it would pass an Adiabatic calculation) I have found like You and many others I suspect, that N-E faults are common, they can sit for years on 3036 protected circuits with no effect, So the Moral of the story is ; Test, Test and Test again, no way can you bang in a new CU and hope all is Ok, RCDs can be outwitted!. [/QUOTE]
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Student & Learning Zone - City & Guilds
What fault can turn a TT into a TNCS and disable the RCD?
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