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New build future planning Solar PV

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  • 17-04-2022 9:24am
    #1
    Registered Users Posts: 333 ✭✭


    Just finishing building at the moment (bad timing) I'm wondering if anyone could advise me what ducting I may need to lay out to make buying PV panels in a few years a more straightforward process, my PV panels would be on a single storey part of my house with no attic access so my question is how would I get power from the panels back to my Meter do I need to install ducting in footpaths on the outside to my meter box or how normally is power brought from the panels to the meter, footpaths are not yet poured?



Comments

  • Registered Users Posts: 12,095 ✭✭✭✭KCross


    The wiring would be back to the consumer unit, not the meter box so footpaths won’t help there.


    The main consideration is you would need to mount an inverter somewhere which electrically sits between the panels and the consumer unit so you need to figure out where that would be mounted and then figure how to get the wiring to and from that



  • Registered Users Posts: 528 ✭✭✭mike_2009


    my panels are on the roof and the inverter is in the dining room. They ran DC cables through the root, into the attic, across to the side of one of the upper bedrooms and down into the kitchen and over to the inverter internally. They then drilled into the front extension to run AC cable to the consumer unit. Do you have a site for an inverter? Any internal route to get the wiring between them? If not you'll have to go outside with some type of trunking....

    My Car Charger has external trunking between it and the nearest point to the consumer unit and they drilled a hole to bring it in there....

    Hope this helps.



  • Registered Users Posts: 333 ✭✭briangriffin


    Thanks for the replies lads excuse my ignorance now but how big is the consumer unit and does the consumer unit have to be near the meterbox? Or whats its function?, I have a vaulted ceiling where my panels will be and no access to the attic from it, I also have the option of putting the panels on my garage roof but again would that be more difficult to get power back to the house?

    From what you've said I need a site for a consumer unit and a site for an inverter are these big units and is there a specific place they need to be or can't be due to regulation?



  • Registered Users Posts: 528 ✭✭✭mike_2009


    The consumer unit is your main fuse box inside your house where you go when a circuit trips and you need to reset it to get power back to a plug or whatever. The Meterbox is outside and has the ESB meter and mains supply that comes into the house. The PV equipment will only connect to the consumer unit - they'll install a new circuit and fuse into that box when commissioning.

    The plan was for my inverter to go into the attic (salesperson) but the Electrician when they arrived said no - can't as they need to keep away from flammable surfaces by 1.5 meters and my roof pitch is very low. We scrambled around for an alternative - back of wardrobes, in an ensuite (!) but settled on behind the door in the dining room which is the other end of the same room as the kitchen.

    That's a tricky route - once it's been build. There may be a service cavity behind the plasterboard if you're lucky and a few small holes may be all that's required to route the DC cables. The inverter is beefy enough depending on the model, if you get a battery also total size could be:

    Inverter: 50cm wide, 40cm high, 23cm deep

    Total including battery - mounted on cement board attached to wall, 1.2m high x 1m wide, 25cm deep. The board is mounted so that the top of the inverter is chin height for me. Easier for them to work with and keeps it off the floor. I have a fire guard in mind to keep prying hands away if kids ever becomes an issue.

    Siting the inverter - keep away from water and 1.5meter from roof joists!! SEAI have a checklist for their installers and it's very rigorous. It is probably on their website somewhere. Labels have to be perfect. But there are plenty of options for siting but they do need to connect to the panels and the consumer unit, that's key. You could run DC cables outside the house under the eaves if you can route them around to outside the consumer unit/inverter? If you get a quote / see if you can get a site visit but from an installer/electrician, or a really technical sales person and they'll size up this for you and give you some options to think about.....

    Ground Mount if you have the space would be amazing, the mounts can be pricey though but if you DIY a bit it can save a lot of money. If you can change the angle twice a year it gets even more efficient but if it's a large array I'd go for more panels over tilting as panels are cheap. You're limited to 6kW panels I think if you're single phase which is a pity, more if you have three phase. You may be able to get around this if you aren't connecting some to the grid to keep below this, some sub panel perhaps that blocks export? Not sure if this is a thing but it's a shame if you are able to use that extra electricity somewhere.....



  • Registered Users Posts: 297 ✭✭spose


    If your garage roof is big enough I’d put it on that and inverter and batteries can all go out there and not take up any real estate in the house. I presume you’re going to put power in the shed anyway so all you’d have to do is oversize that cable between house and garage and then you can put another smaller consumer unit in the garage. Any PV installed later can connect to that consumer unit without having to do any work in the house. At the same time I would run 2 or 3 lengths of cat5 cable from the consumer unit in the house to the garage. Can use that then for any ct clamps needed later or for connecting inverters instead of Wi-Fi



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  • Registered Users Posts: 333 ✭✭briangriffin


    Thanks Mike, can you explain how the panels supply electricity to the house, so at the moment I have esb coming from outside to my utility, I was assuming my pv panels would connect into my meter box where the esb connects in or can the consumer box just be patched in anywhere?

    I do have a service cavity in the kitchen and would have a spot actually in a corner to house the inverter and the consumer unit neatly alp it would take is a a bit of patching the plasterboard, that's great to know thanks for the advice, what would you advise about maybe using the garage to put the panels instead of the house pros or cons?

    Thanks Sp - I'm actually thinking this might be the best way to do this my only concern is my garage is beside my house both are south to SE facing roofs so I'd have to check if there is too little distance between them, I have a service manhole from my garage to my house( I've power coming from my house to the garage at the moment) so it would be very easily done, what size electric cable would I need in the garage?



  • Moderators, Home & Garden Moderators Posts: 5,904 Mod ✭✭✭✭graememk


    Regarding the consumer unit for the house,

    It's the fuse box, it's where all the wires from your plugs/lights/oven/whatever go to and a cable from the meter box goes to it.

    Your cable to the garage will also need to go into it.

    As for size of cable to the garage, I'd be putting in as big as possible, just for future proofing a bit, eg if you end up with your inverter out there or an ev charge point 10mm2 minimum, or even 16.

    Do you have a plant/mechanical room? Eg somewhere has has all the equipment for the house?



  • Registered Users Posts: 333 ✭✭briangriffin


    Thanks G, so the consumer unit needs to be fed into from my existing meter box then, that presents the problem with putting it in the house getting a cable to it through the house, unfortunately we have no plant room and the utility is very small so it's cramped enough as is with the air to water unit, I'm thinking the garage is my best option if it is getting enough sunlight the its a big garage so the south facing roof might be the answer for me, I'm running cables to it at the moment so it's an ideal opportunity to leave it handy for myself by putting in the extra ducts and running cat 6 etc as thr lads wrre saying above so its all there when I can afford the pv.



  • Registered Users Posts: 528 ✭✭✭mike_2009


    That garage sounds like a better idea - just need to check the roof is sound and can take the panels. There are a few solutions including plastic wedges you fill with water to steady them (flat roof?) but weight will need to be checked, otherwise orientation on a pitched roof can be modelled. Good timing in any case!



  • Registered Users Posts: 12,095 ✭✭✭✭KCross


    I think you might be still a little bit confused about the consumer unit?

    The consumer unit has nothing to do with whether you have Solar PV or not. Every house has one and your house already has it, or will have it, once the electrician wires the house up. All wiring in the house coverges to the consumer unit. You cant easily move that and the electrician will have already decided where that is going to be placed if you are already at wiring stage.

    Wherever the electrician decides to put that consumer unit is what you will need to wire the Solar PV inverter back to.

    So, you need to talk to your electrician and ask him where is your consumer unit going to be and then plan how you can run additional wires back to it from the Solar PV inverter in the future. The inverter can be placed anywhere indoors really but it will need to be wired back to that consumer unit so that the energy from the panels can be fed back to the house.


    You wont be wiring the Solar to the meter box.



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  • Registered Users Posts: 333 ✭✭briangriffin


    It's a pitched roof garage so I'm sure it will be ideal if the sunlight is not blocked by my house which I believe it's not but will make sure

    The consumer unit is what would have been called the fuse box in my old house then is it for all my electrics so my esb connection is coming into that and my PV panels would also have to connect into it to allow them to power the house? That unit is in my hall.

    That would make more sense to be fair to feed into the house, thanks for the clarification 👍

    Last question Smart meter yes or no my understanding is you need one for PV panels but if I'm not going to put them in for a couple of years the standing charges on the smart plans are much higher than the ordinary ones, New connections hadn't an option to go for the ordinary meter built I think I can request one?



  • Registered Users Posts: 12,095 ✭✭✭✭KCross


    The consumer unit is what would have been called the fuse box in my old house then is it for all my electrics

    Yes

    so my esb connection is coming into that and my PV panels would also have to connect into it to allow them to power the house?

    Yes, kind of.

    When the ESB connect your house to the grid they will run a cable to the meter box from the transformer on the pole. Then your electrician will run a cable (called the "tails") from the meter to your consumer unit and then all the wiring of the house "fans out" from the consumer unit. So every wire in the house terminates back to the consumer unit, not the meter box.

    And the same is true of the solar inverter, which is used to connect the panels to the house.

    That unit is in my hall.

    So your next step is to decide where the Solar inverter is going to be mounted. Once you decide that you then have to figure out how you can run cables from the panels to the inverter and another set of cables from the inverter back to the consumer unit in your hall.


    Last question Smart meter yes or no

    I'd say no, regardless of whether you are getting Solar or not. They represent really bad value for money right now.

    If you have a heat pump and/or an EV then you should request a day/night tariff. They will probably give you a digital meter which supports both 24hr tariffs and day/night tariffs.



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