Carrerahill

Based on 6A on a 48V system, the volt drop would be about 2.2V at 10m of 1mm² (0.0185 Ohms)- at 25m it would be 5.55V. You would want to use about 3.0mm² (0.00615 Ohms) wire for anything up to 26m run, 4.0mm² (0.00471 Ohms) for up to 34m and so on. If it was 24V it would be even worse - around a 8.5mm² cable for 6A at 34m. I think (know) the whole thing could be done by an individual with a lot of time on their hands and a real passion for DIY systems but it's not going mainstream. 240V supplies are becoming safer and safer and I just don't see an issue with using 240V throughout and using SELV power supplies at source. We are now doing warehouses with HV (11kV) distribution within them to cut down on cable sizes and site transformers around the warehouse as needed - so things are sort of going to opposite way. You talk about making your own lights, assume you will make an LED luminaire? Then its SELV anyway and you are running it from a driver/transformer anyway.

Yes, we wanted to increase the overhang of our roof and we just nailed pieces of 2x5's onto the side at the end of all the rafters, stung a line along them and recut the tail. Job done.

I spray MDF with satin 2k paint. Did the under stair drawer units, alcove units, skirtings and window sills like this. Tough as nails (its what they put on vehicles) - you need to be setup to spray this though or find a paint shop who will do it for you. Water based is never as tough. You really need to paint prior to fixing then just touch-up though as you cant be spraying 2k in the house.

He mentions flats roofs, different pitches, on separate inverters. I accept that of the existing overall it’s still a 40% increase, however, in practise this is only a 750W increase in generation.

Agreed - my mistake, I do forget I have an unorthodox setup (I am not using it for payments of any sort, just global export monitoring).

Use the sunshine solar system builder. I would allow about £500-1000 for the inverter (depending on functions you want), £50 for cabling, £50 for the 2 isolators. Not sure how many panels you are talking but say £300 for rails and mounting - that is about you. Break the system into easy components. Roof rails, PV panels, DC cables, DC isolator, invertor, AC isolator, generation meter if you want then consumer unit connection. Plenty of companies sell the rails, rails, splice kit, mounting brackets and roof mounting brackets. To work out the rail requirement you just need to know the panel size (usually width) for mounting requirements. For the inverter its fairly simple, size it to your array, a few technical details to consider but its pretty easy. If you are going for a 4.92kW system then I would size the inverter about 4.5kW - you may struggle to get one bang on so I would see if I could go up in power density to a panels that gave me about 5.5kW then use a 5kW inverter. If you can get the roof bit done, get a friendly, imaginative spark in to do the rest - they do exist, I know of about 5.

You get very excited about PV matters! Maybe on paper - in real life? Lets be realistic. Even if there was a noticeable 20% (750W) hike in generation, it could quite easily be attributed to the removal of a immersion heater or other electricity hungry appliance - if you think someone is going to notice a theoretical 40% increase where the overall numbers are less than 10kW then you are giving the system far far more credit than it is due. 3 ways he can do it: Firstly - adds it to his system and everyone stops getting so very excited, or second, he just adds the system to his house for self consumption and any that gets exported is his loss, thirdly he calls them up and asks them what will happen if he renews his panels with more efficient ones, if they accept, he declares his new peak generation capacity (I would go this route rather than trying to tell them I am adding a new system as it's more clear-cut). The OP's annual export figures would be worth reviewing first.

Focal point is the fire, don't ruin it with a TV.

Why don't you just add them, the meter will register more generation you get higher payments. 4 panels won't raise in eyebrows. I had the roofer fit the rails and panels, he connected them up as per my instruction and left me two DC tails which I dealt with from there. I also have an array on the garage and shed. I fully DIYed them. My advice: Just get on with it.

I think it was this sort of order they are trying to stop to be fair. They started this a year or two ago. It is a bummer if you only want a £5 of stuff but I can see it from their side too. I always felt guilty buying £3-4 of stuff and would usually find some other things to buy, but the fact you could buy a 60p strip of resistors and it would come Parcelforce the following day was a bit mad, if not brilliant at the same time.

This has begun I would say, I am in building services consultancy and we have had to jump through hoops and over a few hurdles over the past 18 months to get buildings to work, the steepest learning curve was getting buildings to comply with the London Environmental Strategy, once we solved that it was easy to make other buildings work up and down the country. We are recovering heat left right and centre and working with more and more onerous figures and thinking outside the box. No training though, as engineers we saw it as a problem to solve and we got on with it. Most of the "training" would be through CPD's which are usually delivered by manufacturers, always with a hidden sales pitch (CPD's are meant to be unbiased, and cannot directly involve a product/service they sell). But it is always then followed by, "Oh by the way, we can sell you these which complies with all of that". So they are not good forums for learning. The electrical regs had a shake up in September, you buy the book, digest it and design to that standard, very little is via training. I will give you a key example of "training" that caused issues. Gyproc went around architects, builders and building control departments and did a CPD on fire rating plasterboard walls. It was pretty common to use a double sheet of 12.5mm to achieve 1 hour fire rating. However, Gyproc wanted to sell fireboard so basically did a CPD and released a white paper which muddied the waters and clouded the BCO's better judgement, which was the dawn of fireboard and 12.5mm board to get your 1 hour! The only person who won was the manufacturer and maybe the sheeting contractor.

They are so blind, so unimaginative, so lacking in foresight and ignorant.

Bravo! I doff my cap!

Nonsense. What happened to pragmatism. Guy is doing a temp job on a house that is getting demoed. Approved contractor? Go over to the EV Charger thread just now and read the contempt for "approved" and "certified" "clubs" - you will get some poorly trained muppet with a pipe shooting beads into your wall regardless. I guarantee you that the majority of this forums members (clearly not all), would be more knowledgeable and competent than most of the people who come to install it and will understand how a building goes together far better. Most of us on this forum build buildings, all in compliance with regs and building standards, of course someone can buy the approved material and blast it into a cavity.

I would just apply for it, if you don't build it then fine. Just make sure it is not a condition of the application.

It will come. Someone will deem themselves an expert and form a club and get all the homeowners fearful if they don't use a "club" approved installer - of course, club approved just means paid up member. All a money making scam - which is partly why I treat most of these club like approval organisations with complete contempt. When I first worked in consultancy I had all my paid up professional memberships - then I decided not to pay any of them and see what happened - nothing happened, I just saved about £389 a year.

True, but there is a silly club for PV stuff and I have not followed any of that either. I am not anti-establishment, but very anti-pointless-moneymaking-scam-club. If, it served to ensure these guys were good, professional, safe, etc. and had true meaning, I wouldn't have an issue, but if you use them to complain about an installer, nothing happens.

Just make one. All an EV charger is, is a contactor and some electronic circuitry to switch it on/off. You can buy an EV charge control protocol module which takes the DC signal from the vehicle and switches the contactor on to start/end charging.

Yes, sounds very suspect. I am in a 1960's build with 2019 modern rear end extension, retrofitted insulation to original building, less than £5 a day and heating to about 18°. Makes me sick that people are conned out of their hard earned, assuming they will get a "good" build from these cowboy builders.

If it was me I would try and close the hole as best I could with bits of brick and mortar around the services, then use fire rated foam to seal the penetrations. I appreciate it may not be possible to brick it up, but even if I could shrink the hole with some bricks here and there to reduce the size a bit I would. You say the pipes are central and the wires go to the sides, could you fit 2 bricks in on end, one about 50mm from each side to create 3 rectangular openings? It also means you have smaller foam fills and if you can compartmentalise the services into smaller penetrations it would make the whole thing a lot neater.

I had this detail in my extension on a sloped section and I just scribed the PB with my knife at an angle several times in quite deep and it came off with a roughly mitred edge. The issue is the edge may be prone to cracking, there are options here. You could put a bit of dot & dab adhesive along the edge to get a good ridged joint.

I'd strip the roof and add box profile sheeting if doing it on a budget or upgrade structure and tile/slate if I wanted to do a really nice job of it. Inside I would insulate and PB to a new build house spec. or better.

The weekly struggle to find capacity for developments, the inability to get LV connections, the requirement for a substation in practically every development now, even a small block of flats, developments that have been shelved due to the LA planning rules stating, for example, min. 20% of car parking spaces must have EVC, apply to DNO, sorry, no capacity for 5 years in this area and £300,000 please. DNO's telling us HV ring mains are maxed out because so and so down the road just put another MW tranny on it... Local residential infrastructure was sized on an ADMD of 1.5-2.5kVA for gas heated homes, start adding EVC to each home... The situation is not good.

Check your figures! Hunterston B produced about 6000 GWh annually! 2021 isn't a realistic year to use. We need to see what 2023-2024 is, 2021 was depressed and will remain depressed due to a lot of Covid related shutdowns and low occupancy levels in buildings. Anyway, the UK uses about 250TWh annually!

Installed capacity (2020) is 75.8GW - that will include PV, wind etc. and plants which do not normally run and things like pumped hyrdo etc. We are pulling about 40.2GW as of 12:45 - OK great, heaps spare. However, when you go and ask for a connection and they tell you the local HV network is maxed out and you shall need to pay and wait for upstream network reinforcements, does it still comfort you knowing there is about 30GW spare capacity (it will be lower as said, includes sources that will not be available)?