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Wiring system for solar PV

lyledunn

Neat enough job and probably technically compliant, but is it sensible to put the DC side conductors in metallic trunking and conduit even if they do meet the class 2 or equivalent requirement? 

I am aware that there are SWA cables specifically for solar PV, so I guess there is not much difference if the SWA is earthed. However, on a slightly different point, if these SWA DC cables are buried, what is the point of earthing the wire armour?

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    Just thinking aloud...

    A lot of the early regs on earthing talk about preventing metalwork becoming "charged" - these days with almost everything a.c. we tend to think of that happening either because of insulation breakdown or capacitive coupling as any tiny leakage of a.c. currents will discharge on the next half cycle as easily as it charged on the first half-cycle. With d.c. power though I guess there's a potential for a charge to slowly build up on the unearthed metalwork over a very long time just due to less than perfect insulation (it may be many mega Ohms, but it's still not totally perfect) - if the metalwork is substantial then it could hold a reasonable charge (just like a capacitor) - maybe enough to give a jolt if it discharged to Earth via human contact?

      - Andy.

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  • 0

    Just thinking aloud...

    A lot of the early regs on earthing talk about preventing metalwork becoming "charged" - these days with almost everything a.c. we tend to think of that happening either because of insulation breakdown or capacitive coupling as any tiny leakage of a.c. currents will discharge on the next half cycle as easily as it charged on the first half-cycle. With d.c. power though I guess there's a potential for a charge to slowly build up on the unearthed metalwork over a very long time just due to less than perfect insulation (it may be many mega Ohms, but it's still not totally perfect) - if the metalwork is substantial then it could hold a reasonable charge (just like a capacitor) - maybe enough to give a jolt if it discharged to Earth via human contact?

      - Andy.

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