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Solar PV Wiring - Question

  • 15-09-2019 10:14am
    #1
    Registered Users Posts: 435 ✭✭ mike_2009


    Hi,
    Just wondering what people's thoughts are on this - the Solar PV install I had done recently poked the DC cables through the felt in the attic instead of routing it a different way. When I queried it they said the tiles are to keep the rain off, I always thought the roofing felt was a backup? If I ever get a leak above this location won't I be in danger of water ingress, in the worst case it runs down the wires into the inverter?! I would have used the overlap to push the wires though....
    Interested in any observations as it's my first encounter with PV in my own house....Thanks!


Comments

  • Registered Users Posts: 562 ✭✭✭ bunderoon


    mike_2009 wrote: »
    Hi,
    Just wondering what people's thoughts are on this - the Solar PV install I had done recently poked the DC cables through the felt in the attic instead of routing it a different way. When I queried it they said the tiles are to keep the rain off, I always thought the roofing felt was a backup? If I ever get a leak above this location won't I be in danger of water ingress, in the worst case it runs down the wires into the inverter?! I would have used the overlap to push the wires though....
    Interested in any observations as it's my first encounter with PV in my own house....Thanks!

    Spot on. Cowboy approach. And to see that the seam is only inches away to feed the cable under and in.....

    If the cable is to stay there, is there slack on the cable so you can atleast loop it back up and then down again to create a water drop area and have crude protection in the shape of a pot to collect the drops... Far far from ideal, but abit of protection if the cable isnt to be re-routed as it should.


  • Registered Users Posts: 1,834 ✭✭✭ garo


    Yes this is not compliant. If you look at the SEAI Code of Practice it talks about bringing the wires in through the felt overlap: https://www.seai.ie/publications/Code-of-Practice-Solar-PV-Grant.pdf
    And did they drill through the tiles? The angle of the cables suggests that they did.


  • Registered Users Posts: 435 ✭✭ mike_2009


    Thanks for that - found that section:
    "Where the DC cables penetrate the roof surface and membrane a waterproof system
    shall be provided to ensure that the cable way cannot affect the weathertightness of
    the roof. This will include a membrane grommet if required."
    I thought they lifted the tiles to install the hooks. I guess if I end up asking them to remove it all I'll have to verify for myself.


  • Registered Users Posts: 2,820 ✭✭✭ air


    If you are concerned, you could cut a square of felt or similar and make a slot from one side to the centre point. Plaster it with roofiing sealant and install it over the cables on the underside of the felt with the wires in the centre.
    You could also squeeze some sealant around the cables first where they come through.
    They are correct to an extent that felt is just secondary protection to buy you some time to spot and rectify the cause of a leak (broken tile or whatever).
    Even as is you'd be very unlucky if it ever caused you an issue.


  • Registered Users Posts: 1,834 ✭✭✭ garo


    It is not trivial to locate leaks sometimes. So anything that may compromise a roof is a no go in my book. I know because after multiple attempts to fix a leak I eventually ended up retiling and re-felting fine which cost a fair bit.
    Unlikely that will be an issue in OPs case and what air suggests is a good solution now that the deed is done.
    I don’t have the inverter located in the attic so my PV cables are fortunately all external.


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  • Registered Users Posts: 2,820 ✭✭✭ air


    Yes I did the same, brought the PV cables through the tiles, out through the soffit, down the wall and into a duct to the shed.

    I really don't think it's a huge issue and most houses would have plenty of far worse holes in their felt than that in the OPs photo.


  • Registered Users Posts: 1,834 ✭✭✭ garo


    So here’s the bit I didn’t like about my wiring. They didn’t go through the soffit but instead went around it and the fascia. The wires seem secure enough but look ugly and I am concerned about UV degradation. I haven’t made the final payment yet. Should I insist on them fixing it?
    When you talk of bringing the wires through the tile do they just rest on top of the felt and battens? Did you bring the wires through a waterproofed notch or a vent tile? I have an EW orientation so there are two sets of wires. And they ran one set over the peak tiles. Is that a no no?
    @OP: sorry for hijackibg your thread.


  • Registered Users Posts: 2,820 ✭✭✭ air


    There's no issues with UV as any PV cable should be UV stable, it's designed to be used outdoors after all.

    I used a tectite multi-cable flashing to bring the cables through the tile, I have 2, soon to be 3 pairs of cables coming through the roof.

    I used rubber grommets then in the soffit to protect the cables where they come through the aluminium soffit.
    To be honest there's probably nothing really wrong with going around the fascia once the cable is secured from movement so it doesn't get abraded over time.
    I can imagine it might not look amazing but my own isn't particularly beautiful either tbh!


  • Registered Users Posts: 1,834 ✭✭✭ garo


    Thanks for that. I might check to make sure hey added rubber grommets and if not ask them to add them in the critical points. Cables are pretty snug with no slack at all so that’s good for abrasion.


  • Registered Users Posts: 5 ✭✭✭ Fosulli


    Can anyone help me - I am about to install PV panels - my mains wiring has 2 feeds from the ESB meter. One feed to the house fuseboard and the other feed to a fuseboard in my shed. If I have PV panels, inverter etc. installed on my shed and connect to the shed fuseboard, will that still feed my house supply before dumping power back to the grid? Thanks for any help!


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  • Registered Users Posts: 1,834 ✭✭✭ garo


    Fosulli wrote: »
    Can anyone help me - I am about to install PV panels - my mains wiring has 2 feeds from the ESB meter. One feed to the house fuseboard and the other feed to a fuseboard in my shed. If I have PV panels, inverter etc. installed on my shed and connect to the shed fuseboard, will that still feed my house supply before dumping power back to the grid? Thanks for any help!
    It depends. Do the two wires meet up before the meter? If so it should work. But ask your PV installer and get them to guarantee it.


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