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Hi all, thanks for answering all my dumb questions so far...

So I've decided to install PV panels and a battery storage system, and I've decided to do as much as possible myself, because finding a local installer who will offer a choice, rather than just a 12 grand "solution", seems impossible.

Given the time of year, I think that getting the inverter and batteries up and running is a higher priority than the panels - I'll probably buy a bundle including panels and then find someone to put them on the roof once the rest of the kit is installed.

My electricity supply is currently a pretty standard setup with the cable into the house going to the main fuse / earth box, then the meter, then consumer unit, with no isolator. I assume the inverter output will just be "spliced" in between the meter and CU, so should I add an isolator switch and junction box between meter and CU? Obviously this is something I'll need to get a proper electrician to do. Then I'll be able to isolate the entire house, to safely connect the inverter.

Is this the right approach? Once I've got the isolator fitted I am quite confident that I can install the inverter etc and wire it in. Is this allowed, and do I need to get a professional to certify the installation before turning it on?

This is my idea of what's required (just the mains wiring, not including PV, batteries etc), where the items in the red box are installed by an electrician and the stuff in the green box can be installed by me.



Many thanks for advice. I'd like to get the kit I need ordered soon, as there seems to be about a month lead time on batteries, and I'm sure they'll sell out as fast as they arrive!

The law around what you can and can't do yourself is a bit of a mess, IMHO. The wiring regulations and all the rest of the stuff, like MCS etc, are not law, in the sense that failing to comply with them carries any sort of penalty or risk of criminal action. The only laws that can be broken by DIY'ing stuff that do carry a criminal penalty are the building regulations. However, IIRC there is something like a two or three year window when you can be prosecuted, after that you're effectively immune from any criminal action. Bit like the US concept of a statute of limitations. Clearly there are potential consequences around liability, if something were to go badly wrong and it could be pinned on poor workmanship, or failure to comply with regulations.

Building regs cover things like the structural integrity of buildings (may apply to roof mounted panels - not sure TBH) and certain aspects of the electrical installation (new circuits, circuits installed outdoors, circuits installed within an area like a bathroom). They also apply to things like the height of switches and outlets and a few other odds and sods that really only apply if there is more going on than just a bit of relatively minor electrical work. Building regs don't cover electrical installations in Scotland (yet) I believe, I think Part P is just something that applies in England and Wales.

In theory (not suggesting this should be used as advice) anyone can do all of the electrical installation work as long as it complies with the regulations. The fly in the ointment is the need to comply with the building regs AND to have that compliance proven and lodged on the register. You can (in theory) get any building control body to inspect, test and lodge the building regs compliance chit (which is just the electrical installation certificate) but it's expensive, around £400 typically. This makes it cheaper to use a Part P accredited electrician (not all are).

Probably the cheapest way to go, if you feel you're competent, is to get an electrician to run two new circuits in (grid supply and EPS supply) and terminate them in an enclosure. Those circuits can be signed off in accordance with Part P and then you can legally DIY everything from then on. You are OK DIY'ing most stuff on an "existing circuit) and the wiring regs don't really apply in any significant way to the low voltage (battery) side anyway. This all assumes competence with electrical installation work and the ability to be able to test everything to ensure it's safe.

We call it "bodgineering" (hopefully without the bodge) ...a longstanding affectionate & oft descriptive term from a long time ago, in a forum far, far away

Nb, Gravyminer (aka speccy bloke) & Frotter are sorely needed, anyone in contact?

D.M. ..have you seen Nowty's means of legitimate circumnavigation of the rules (done properly) such as his *cough* "ladder storage" or piecemeal add ons of wall mounted extra panels (which may be also masonry weatherproofing that also soaks up some energy, incidental to the main.

Whilst half assed & lethal is a definite no no many here are part of a forum that existed since way back in the day (maybe pre 2004) a long time in terms of, solar efficiency, govt efficiencies via govt inadequacies, local & national legislation, many a conundrum posed, some even solved.

No question is dumb, unless it is asked without research as to pre-existing answers laid down before & in the open archive creating a rinse & repeat pattern of same question answered on 20 "bloody threads" ..resurrection of old threads is more fun & less disjointed.

I think there is often too much fuss made about laws, when in reality there is nothing wrong with DIY work as long as it meets the regs and is safe. In my limited experience, often a committed DIY'er will do a better job than some that call themselves professionals. I've seen some pretty poor "professional" work over the years.

Even if laws are broken, in this case just a failure to get building regs approval, then if the work is actually compliant and the only issue is the lack of a bit of paper, then it seems very unlikely that any legal action could be taken. Worst that might happen is a request to get retrospective building regs approval if for some reason building control got wind of work being done that they didn't know about (before the "statute of limitations" period expired).

Edited to add this link: https://www.planningportal.co.uk/applic ... egulations

Seems the local authority have up to two years to take action, after that you're pretty much home and dry (with the possible exception of when you come to sell the house):

Prosecution and enforcement notices

A local authority has a general duty to enforce the building regulations in its area and will seek to do so by informal means wherever possible. If informal enforcement does not achieve compliance with the regulations the local authority has two formal enforcement powers which it may use in appropriate cases.

First, if a person carrying out building work contravenes the Building Regulations, the local authority may prosecute them in the Magistrates' Court where an unlimited fine may be imposed (sections 35 and 35A of the Building Act 1984). Prosecution is possible up to two years after the completion of the offending work. This action will usually be taken against the person carrying out the work (builder, installer or main contractor).

Alternatively, or in addition, the local authority may serve an enforcement notice on the building owner requiring alteration or removal of work which contravenes the regulations (section 36 of the 1984 Act). If the owner does not comply with the notice the local authority has the power to undertake the work itself and recover the costs of doing so from the owner.

A section 36 enforcement notice cannot be served on you after the expiration of 12 months from the date of completion of the building work. A local authority also cannot take enforcement action under section 36 if the work which you have carried out is in accordance with your full plans application which the authority approved or failed to reject.

An appeal against a section 36 notice may be made to a Magistrates’ Court under section 102 of the Building Act.

Where an approved inspector is providing the building control service, the responsibility for checking that the building regulations are complied with during the course of your building work will lie with that inspector. They will usually do this by advising you.

However, approved inspectors do not have formal enforcement powers. In a situation where the inspector considers your building work does not comply with the building regulations and there is a refusal to bring it into compliance the inspector will cancel the initial notice. If no other approved inspector takes on the work, the building control function will automatically be taken on by your local authority. From this point on, your local authority will also have enforcement powers set out above where it considers this necessary.

Glancing at your opening solar thread, i dont think i saw direction, location of the proposed install ?

Many folk widh they'd gone bigger with their panel arrays, are you heavily limited by roof angles, neighbours shadowing potential, or do you have infill space ..such as solar pounding your driveway & superheating your cars? ...ie room for a solar lean to car-port assembly?

(giving you a heads up here, EV's have / need overheat protection, the interior can soon rise to 35c & beyond, tesla cut in is 40c ..& spends a lot of time warning us (3 of 4 seasons, & not just due to the glass roof)

I'm a big fan of planted shading (uk homes & driveways tend to be plant barren over time) so solar car ports offer multiple practicalities in terms of shade for car & home, wind buffer, potential for oversizing a solar set up & having energy feed potential to the grid or your car down the line.

Batteries are the expensive bit of kit previously held by that of solar panels, but whereas you can typically slot in another battery or two in a stack you got wired & ready for, it can be a different deal doing a smaller additional amount of solar panels second time round, so please scrutinise the property for opportunity that may future proof you in a variety of ways & help load any eventual battery stack along the way, losing spare self grown solar electrons to the grid may be annoying but a bunch more panels are cheap in the scale of things, & trying to match up with close specification that doesnt drag your initial kit down latterly.

& dont forget to insulate the hell out of the place!

Mr Gus wrote: ↑Mon Oct 17, 2022 11:07 am Glancing at your opening solar thread, i dont think i saw direction, location of the proposed install ?

Many folk widh they'd gone bigger with their panel arrays, are you heavily limited by roof angles, neighbours shadowing potential, or do you have infill space ..such as solar pounding your driveway & superheating your cars? ...ie room for a solar lean to car-port assembly?

Thanks for the feedback ... at this point I'm more concerned about the practicalities of wiring in the inverter and batteries, rather than the panels.

However, to answer your questions, my house has a south facing (about 200 degrees) roof which is 4.2x5.8 metres. I think I can get a 3x3 array of panels up there. Say the panels are 1.2 x 1.7 that's 3.6 x 5.1 total occupied by panels. Most of the inverters I've looked at have 2 solar MPPT inputs, so I assume that gives me capacity to add another string of panels in the future? I could panel my garage roof but it faces E/W and is in the shade of the house a lot of the time, so not a prime location.

That would give me 3.6kW peak of PV (assuming 400W panels) and our daily usage is approx 5.2kWh.

The house is quite small and already well insulated, although I am looking in to adding more in the loft space.

dangermouse wrote: ↑Mon Oct 17, 2022 11:38 am Thanks for the feedback ... at this point I'm more concerned about the practicalities of wiring in the inverter and batteries, rather than the panels.

There's no reason why you can't mount the inverter and batteries and do all the battery side wiring yourself. You aren't in breach of any rules by doing this bit.

The only wiring that is covered by a law (only in England and Wales I believe) is the mains side from the consumer unit to the inverter. I'm pretty sure that you are fine doing the panel installation and DC wiring as well, the only possible point that may fall under the building regs with that bit may be the physical mounting of the panels. If a standard panel mounting system is used for the type of roofing you have, and the guidance as to how to install it is followed, then I doubt there are any issues at all with this bit, either.

I've heard of some people agreeing with an electrician to do all the physical stuff, like mounting bits and bobs and running and fixing cables, then getting the electrician to do the final connecting up and testing. Not sure how easy it is to find an electrician to agree to something like this, though. I've always thought it was something that probably only works OK if you happen to know a friendly electrician.

Just been there, done that!

We had a Tesla Powerwall installed by approved installer and had the inverter wired into the Tesla gateway (effectively consumer unit) by qualified leccy. He also tested all three strings and wired in the DC side breakers. I ran all cables before he came to save time. He also insisted on earth spike as we have installed on purpose built new steel clad "shed"

Interestingly, and I await a response, Scottish Power Energy Networks allowed me to apply by G98 application. I explained to them my inverter is G100 compliant and that I will export limit to 3.6Kw by means of inverter CT. We shall see how well that goes down but application went in a week ago and nothing heard to date

Welcome!

Mr Gus wrote: ↑Mon Oct 17, 2022 10:33 am No question is dumb, unless it is asked without research as to pre-existing answers laid down before & in the open archive creating a rinse & repeat pattern of same question answered on 20 "bloody threads" ..resurrection of old threads is more fun & less disjointed.

.

Reading yr initial post I am prompted to recommend this link viewtopic.php?f=14&t=1401
and this one viewtopic.php?f=14&t=1290 as there is a lot of explanation there of various aspects of inverter installation, you can't just "splice in" to the meter tails as you suggest.

You will certainly need various RCDs and mcbs and very likely a second consumer unit to house them, especially if you want to use the UPS capability of the battery inverter, and this would probably involve some re-arrangement of your existing house circuits. As well as the "REC isolator" in the meter tails you might consider installing a Surge Protection Device at the same time.

There is a link in the above (and elsewhere more recently) to the IET guidance on earthing which you also need to know about.

Here is a more detailed list of questions which might help with sizing etc:

What is your incoming supply (phases, amps)
Have you got an earth rod (TT supply) or do you use the supplier's earth (TN-C-S/PME)?
Annual consumption peak (kWh)/off-peak (kWh)

What is the typical load profile in kW (a) at night (fridge, freezer, computers, TV on standby etc) (b) peak - probably while cooking supper with many lights on if you cook with electricity (c) any electric heating (d) how is the water heated

What is your present/proposed PV setup (panel and inverter type and rating) and annual yield (kWh)
Do you want it to work during a power cut

Do you want the batteries to supply the loads in a power cut and for how long
(a) all of them (?kW) (b) only part (?kW) (c) if so will it be reasonably easy to split them into two groups of circuits at your consumer unit (d) no/none/don't care

Anything out of the ordinary for a normal domestic setting

Enjoy!

Thank you very much, I shall read the links you posted and report back with answers!