TonyT Posted July 9, 2022 Share Posted July 9, 2022 25 minutes ago, Dillsue said: And immediately following that para it refers the reader to the MCS web site, yet theres absolutely no requirement to use MCS installers which the para infers is a requirement! As with the addition of any circuit to a domestic install, a new PV connection needs to be tested and inspected by a part P accreditted spark or get your local building control to test and inspect. no part P in scotland Link to comment Share on other sites More sharing options...
Radian Posted July 9, 2022 Share Posted July 9, 2022 23 minutes ago, joth said: That guide has other mcs issues Well, it is published as a "Guide" after all 😃 I went nuts trying to tie down the legal requirements for self-installers but a parallel search for cases where people were being prosecuted for not abiding by the "difficult to determine" regulations came up empty handed too - so draw your own conclusions. Part P is obviously a "must" for any new circuit though. 2 Link to comment Share on other sites More sharing options...
JohnMo Posted July 9, 2022 Share Posted July 9, 2022 Simple really Electrician installs the electrical side, he can then sign as the competent person on the G98 form. This cover part P and any equivalent in Scotland. G98 gives you permission to install PV and generate, as long as you retrospectively complete the required paperwork within a given timeframe. Anyone can physically install the panels, but you need the electrician who is signing the G98 form, to do all electrical connections also. 1 Link to comment Share on other sites More sharing options...
SteamyTea Posted July 9, 2022 Share Posted July 9, 2022 2 hours ago, JohnMo said: Anyone can physically install the panels, but you need the electrician who is signing the G98 form, to do all electrical connections also. Does that include the MC3, MC4, Helios H4, SolarLok and Radox DC side, or is that part of installing the modules. Maybe the final connection between the module strings and the inverters needs to be done by a qualified person. Link to comment Share on other sites More sharing options...
JohnMo Posted July 9, 2022 Share Posted July 9, 2022 I took the opinion, that if the electrician did it all and it went bang or something was not quite right, there was only a single person responsible, no he did, she did, not my fault governor. Link to comment Share on other sites More sharing options...
Dillsue Posted July 9, 2022 Share Posted July 9, 2022 1 hour ago, SteamyTea said: Does that include the MC3, MC4, Helios H4, SolarLok and Radox DC side, or is that part of installing the modules. Maybe the final connection between the module strings and the inverters needs to be done by a qualified person. AIUI any cable assembly that is factory made and tested can be installed by anyone ie kettle or computer lead. That principle would cover all the panel MC4 connectors connecting the panels together If the cables from the array to the inverter are prefabricated then the same principle applies. If the same cables are site assembled, as in cut to length and MC4 connectors crimped on, then they need a test and inspection. Unless youve got an inverter and consumer unit with plug in connectors and can buy a factory assembled and tested connecting lead, then the AC connection from inverter to CU always needs a test and inspection. Just my take on things and not a statement of fact!! Link to comment Share on other sites More sharing options...
SteamyTea Posted July 9, 2022 Share Posted July 9, 2022 2 minutes ago, Dillsue said: Just my take on things and not a statement of fact!! It is how I would understand it as well. It is the use of words like can, must, will etc that makes rules and regs hard to read and understand. Link to comment Share on other sites More sharing options...
Radian Posted July 9, 2022 Share Posted July 9, 2022 It's a funny old world. We're trusted not to plough both our C-Max's into each other at 60MPH thus releasing 1.1 megajoules of kinetic energy - yet even dumping a full 32A breaker into earth, in the unlikely event that it takes 1 second to blow, would involve just 1/143th of that. Mind you, now I've worked that out, I wouldn't want to be within 20m of either happening! Link to comment Share on other sites More sharing options...
SteamyTea Posted July 9, 2022 Share Posted July 9, 2022 6 hours ago, Radian said: We're trusted not to plough both our C-Max's into each other at 60MPH thus releasing 1.1 megajoules of kinetic energy Mine is the diesel, so 2 tonnes, 0.73 MJ at 27 m/s. About 7p of electricity. Link to comment Share on other sites More sharing options...
MikeSharp01 Posted July 10, 2022 Share Posted July 10, 2022 15 hours ago, Radian said: thus releasing 1.1 megajoules of kinetic energy I hope it will enjoy its freedom. Link to comment Share on other sites More sharing options...
Radian Posted July 10, 2022 Share Posted July 10, 2022 9 hours ago, SteamyTea said: About 7p of electricity Can make a very loud bang. Link to comment Share on other sites More sharing options...
SteamyTea Posted July 10, 2022 Share Posted July 10, 2022 35 minutes ago, Radian said: Can make a very loud bang. Yes, could probably work out the dB of it know the energy and power it is delivered at. Link to comment Share on other sites More sharing options...
Omnibuswoman Posted July 10, 2022 Share Posted July 10, 2022 17 hours ago, SteamyTea said: It is how I would understand it as well. It is the use of words like can, must, will etc that makes rules and regs hard to read and understand. I was taught that must indicates a legal requirement that is enforceable, can indicates a guideline, and will is ambiguous, and usually deliberately so to lead people to think that something is a requirement when it is not... 2 Link to comment Share on other sites More sharing options...
SteamyTea Posted July 10, 2022 Share Posted July 10, 2022 1 hour ago, Omnibuswoman said: will is ambiguous As it is Sunday, thy will will be done. Link to comment Share on other sites More sharing options...
ProDave Posted July 10, 2022 Share Posted July 10, 2022 On 08/07/2022 at 18:13, Dillsue said: Thats not a correct comparison . We all cook at different times and individual cooker rings in all households will fire at differeing times giving a low diversified import load. If all households on a section of grid installed 16amp of PV export then first sunny day they will all export at exactly the same time and the local voltage could rocket. If the DNOs know in advance that those households have PV they can manage the grid in a timely way. The voltage drop when you draw 16A is tiny. So the voltage rise when you export 16A will also be tiny. If the local grid cannot cope with a few houses exporting 16A then it is going to collapse when everyone cooks their dinner at the same time. The DNO around here does not seem bothered about maintaining and upgrading the network apart from fixing faults when they happen. e.g. a few weeks back our power went off, it was windy so I suspected the usual tree branch brought a wire down. But no, it was the pole mounted 100KVA transformer at the top of our road that had failed. They appear to have replaced it with an even older second hand one, that appears if anything to be smaller than the one it replaced. I really wish the DNO would relax the restrictions on a PV / battery system that is designed not to export. Surely that should be allowed regardless? Link to comment Share on other sites More sharing options...
SteamyTea Posted July 10, 2022 Share Posted July 10, 2022 6 minutes ago, ProDave said: The DNO around here does not seem bothered about maintaining and upgrading the network You live in a rural area, so only a few tens of homes, and a milking parlour are affected. Not the same in even a small town where 1000 houses can be without power for several hours. There is a good chance that we will have energy rationing come this winter. The easy way to do it is via scheduled disconnection. Link to comment Share on other sites More sharing options...
Radian Posted July 10, 2022 Share Posted July 10, 2022 OFGEM even recognise the potential opportunities offered by Distributed Energy Resources (our solar and battery installations) to help them with "Black Starts" on the grid. Some seriously "joined up thinking" is required here. Link to comment Share on other sites More sharing options...
SteamyTea Posted July 10, 2022 Share Posted July 10, 2022 (edited) 17 minutes ago, Radian said: Some seriously "joined up thinking" is required here. I think the problem is not technical, but financial. I did a write up several years ago about adding small amounts of storage (sub 1 kWh) to each house to help grid fluctuations. One problem would be who owns that unit and who owns the energy in it. The decentralising fans would point to a blockchain solution, but that is just energy intensive, even using 'proof of work', fine for a few bearded hippies, not so good for 30m homes doing 540 transactions a day. Easier for a DNO to just plonk a shipping container with 100 kWh of storage next to a local substation. Then there is only one thing to worry about, not 100. Edited July 10, 2022 by SteamyTea Link to comment Share on other sites More sharing options...
Dillsue Posted July 10, 2022 Share Posted July 10, 2022 (edited) 39 minutes ago, ProDave said: The voltage drop when you draw 16A is tiny. So the voltage rise when you export 16A will also be tiny. If the local grid cannot cope with a few houses exporting 16A then it is going to collapse when everyone cooks their dinner at the same time. Not everyone cooks at the same time and even if they did not every element on every cooker would be on at the same time. Conversly, when the sun shines everyones PV will export at exactly the same time. Volt rise can be an issue....our house voltage rises to 255 when the sun shines with a single G98 system. If I connect up a second G98 system (for test purposes), one or other of the inverters will trip on grid overvoltage which is set at 262 volts. Grid limit is 253 volt. Hopefully, that will be resolved when our DNO upgrades our transformer, but you can hopelly see that uncontrolled connection of PV can easily lead to problems. Edited July 10, 2022 by Dillsue Link to comment Share on other sites More sharing options...
SteamyTea Posted July 10, 2022 Share Posted July 10, 2022 47 minutes ago, Dillsue said: Conversly, when the sun shines everyones PV will export at exactly the same time. No it don't, the UK spans nearly a 1 hour timezone, and we frequently have large difference in cloud cover as well. From an academic viewpoint, if we wanted to limit energy usage with the least disruption, we would place maximum generation at times of maximum usage i.e 7 AM for an hour and 4 PM for 4 hours. Hard on emissions, but better on stability as it is easier to coordinate 300 large generators than 70 million people. Link to comment Share on other sites More sharing options...
Dillsue Posted July 10, 2022 Share Posted July 10, 2022 1 hour ago, SteamyTea said: No it don't, the UK spans nearly a 1 hour timezone, and we frequently have large difference in cloud cover as well. For any particular section of the grid, say a large housing estate, the sun shines at the same time, save for the odd passing cloud on a sunny day. I dont think voltage rise nationally is problem as large generators can probably regulate that. The issue is if there was unregulated install of PV or no requirement to notify the DNO, then said section of the grid/housing estate could have problems Link to comment Share on other sites More sharing options...
Radian Posted July 10, 2022 Share Posted July 10, 2022 9 minutes ago, Dillsue said: The issue is if there was unregulated install of PV or no requirement to notify the DNO, then said section of the grid/housing estate could have problems Is it ever going to be a real problem I wonder? What kind of situation would lead to a large number of residents on an estate self-installing PV and not notifying the DNO? The only cases of disruptive behaviour that I can think of relate to low cost, unskilled activities like E-scooters, Drones, Laser Pointers and, many years ago, AM CB radios. Link to comment Share on other sites More sharing options...
Dillsue Posted July 10, 2022 Share Posted July 10, 2022 4 hours ago, Radian said: What kind of situation would lead to a large number of residents on an estate self-installing PV and not notifying the DNO? Those following the advice given on page 2 of this thread, hence the discussion!! Link to comment Share on other sites More sharing options...
ProDave Posted July 10, 2022 Share Posted July 10, 2022 My issue is a PV system with battery storage that is set to NEVER export and only supply the house needs should be allowed in any quantity without restriction. As batteries come down in price this is becoming much more normal. WHY do such systems still have to jump through all the hoops and be subject to power restrictions? THIS is where the DNO's need to modernise their thinking. I am starting to look at this aspect as I might one day want to add such a system and would prefer to do it legally. 1 Link to comment Share on other sites More sharing options...
SteamyTea Posted July 10, 2022 Share Posted July 10, 2022 1 minute ago, ProDave said: My issue is a PV system with battery storage that is set to NEVER export and only supply the house needs should be allowed in any quantity without restriction Short of a totally isolated system, the inverter/auto isolator needs to be if a minimum standard. I think it is reasonable that even if an approved isolating devise is fitted, the DNO still know which, in event of failure, houses to check out. Link to comment Share on other sites More sharing options...
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