Do you have a reference for this please because I've been asking about "loss of mains protection" on several electrician channels with a "what are you talking about" response. But this subject on national grid.co.uk includes the statement "the islanded network may become unearthed" and I noticed Oval on YouTube installing an earth rod in the garden of one of their latest battery installs.
UK Off-grid DNO advice
- Thread starter FlakBlag
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It will require DNO approval to be used legally.
One of the FAQs, says that German users need to register with their electricity provider, so the rule will be the same in the UK.
Of course, as a very small unit no doubt people will plug use it anyway.
The idea of having live pins to connect it though a socket gives me the willies, qv widow maker. Yes, no doubt it has an electronic interlock so doesn't produce AC when there is none present on the plug, but it's still a really dodgy design.
One of the FAQs, says that German users need to register with their electricity provider, so the rule will be the same in the UK.
Of course, as a very small unit no doubt people will plug use it anyway.
The idea of having live pins to connect it though a socket gives me the willies, qv widow maker. Yes, no doubt it has an electronic interlock so doesn't produce AC when there is none present on the plug, but it's still a really dodgy design.
and gals
...If it is under 16A output it will only require DNO notification, not prior approval. He mentions that the manufacturer is "getting" G98 and G99 certification at around the 11 minute point of the video.
That is only half of the equation though. DNO compliance is only there to protect the network, network engineers and other network users from faulty equipment. DNO compliance does not consider IET wiring or building regulations.
I am not a sparky, but understand that for a solar photovoltaic (PV) power supply system connection into an existing final circuit is not permitted under BS 7671. (regulation 712.411.3.2.1.1 apparently!).
This makes total sense as the ring circuit in which the unit would be connected is designed to trip with the 30A mcb supplying that ring. With an addition supply feeding into that ring, the current carrying capacity of the wiring could easily be exceeded if too many devices are plugged in or a fault occurs. This could cause a fire etc. within the house.
Avoid.
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Yeah, connection via the socket is dodgy indeed. What i can't understand is if you set 800W output from this thing and your house is using 200W, the rest will go back to the grid? Not sure about legality of it.
Thanks, it all makes perfect sense. I wonder how they deal with that as people will be buying this kit and plug that it. My understanding is that they use smart sockets to which are connected to the load and device will be outputting the power accordingly. I guess, if circuit consumption is monitored it shouldn't be a problem.and gals
If it is under 16A output it will only require DNO notification, not prior approval. He mentions that the manufacturer is "getting" G98 and G99 certification at around the 11 minute point of the video.
That is only half of the equation though. DNO compliance is only there to protect the network, network engineers and other network users from faulty equipment. DNO compliance does not consider IET wiring or building regulations.
I am not a sparky, but understand that for a solar photovoltaic (PV) power supply system connection into an existing final circuit is not permitted under BS 7671. (regulation 712.411.3.2.1.1 apparently!).
This makes total sense as the ring circuit in which the unit would be connected is designed to trip with the 30A mcb supplying that ring. With an addition supply feeding into that ring, the current carrying capacity of the wiring could easily be exceeded if too many devices are plugged in or a fault occurs. This could cause a fire etc. within the house.
Avoid.
I personally also interested if this can be DIY'ed because I already have solis hybrid, which is currently not grid tied, I wonder if i can offset some idle loads of the house by connecting it to the circuit the same way to supply ~200-400W of idle loads.
They don't deal with it... though if the comments on that youtube are correct, they have already removed it for sale in UK due to non-compliance. I guess there are many dodgy installations that don't meet BS7671 - and also houses going up in smoke due to those dodgy installations.
I disagree. If your house has a standard UK-spec 2.5mm2 T&E ring mains, that wire is protected by a 30A MCB = roughly 7000W. If you then connect a PV supply into that ring mains, via a 13A socket then - depending on the power of the PV/Battery - you could be adding a further 3000W into that wiring - meaning that a total of 10kW could be drawn before the MCB trips. That is not safe. Some will argue that the wire can carry more than the rated amount and/or that the MCB won't trip until a much larger current flow. That is probably true. But what is also true is huge number of ring-mains circuits that aren't... aren't rings I mean. It only takes one bad connection at one of the many 13A sockets around the house for the circuit to actually be two individually connected circuits. The huge disadvantage of the ring-mains is that such a fault can go undetected for years of even decades. Then you have a single 2.5mm2 wire taking all of the 30A. For those of you who have not fallen asleep yet, apparently the reason we in the UK adopted the 'ring' configuration was to save on copper when we were all poor after the war. i.e. we could run bigger loads by sharing the load across two wires.
BTW: I since found the wording of BS7671 regulation 712.411.3.2.1.1... it states "The PV Supply cable (on the AC side) shall be connected to the supply side of the protective device for automatic disconnection of circuits supplying current-using equipment."
Out of interest, what is the reason for not having your Solis grid-tied?
Agree, there is a chance of ring being overloaded due to this kind of setup, however, it can easily worked around by replacing MCBs with lower rate, also there are cases, even in the UK when sockets are on a dedicated circuit. I have some for my panel heater for example. In this case it is arguably safe to do. Also, I'd say that having 31a MCB for a ring circuit is not safe in general, since during the lifespan of the properly ring can be broken and not noticed for a very long time. It is much safer to have 16A on a ring IMO.
PS. Being from Europe I'm shocked a bit by this ring design, in country where I'm originally from people try to put everything on a separate circuit and run wires in metal conduits in wooden structures.
In my case, personally, I don't want to pay for G99 and thousands for installation when I don't really need to export anything.
SenileOldGit
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Thanks for completely derailing this thread, and that also applies to all the people who replied to you, thus contributing to the thread derailment. Every post since your post has not been about the OP's specific question.
Why didn't you just start a new thread? That way, people who want to read about your query can do so, without having to come across it by accident. And everybody else doesn't have to waste their time reading post after post, hoping to see ones that are still actually on topic.
SenileOldGit
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Not for the same length of time as a heat pump, and it isn't a safety issue, and who is going to be using the grid to charge their batteries instead of using their own solar to do it? What happens when an elderly person keeps a 3kW heater on for 16 hours a day during the Winter? Do they need to ask their DNO for permission first? I think you're really reaching here.
SenileOldGit
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Not wishing to sound rude, but what part of "off grid" being the opposite of "grid-tied" don't you understand? God help newcomers who come here looking for advice when there are constant posts which completely ignore what the OP is talking about.
I'm merely giving you the rules. You are required to inform the DNO if you install a heat pump or a 7kW EV charger. I suspect that the reason is so that they can ensure that the grid is capable of maintaining supply, rather than any issue of safety.
As to charging batteries from mains, yes some people do it. If you are on a time of day tariff it can be financially viable to charge your batteries during low cost periods. There are quite a few people doing this, some even have batteries and no PV capability. And the sun doesn't always shine. Were I to charge my batteries from the mains they would consume more than 7kW and charging for the full Economy 7 off peak time may still not fully charge them, so they would be presenting a larger than typical domestic load for a long time.
We certainly do do this, especially in winter when we get little PV. Last winter I was on a tariff which had 10.23p/kWh between 02:00 and 06:00, and 43.99p/kWh the rest of the day. I've only got 4.8kWh of battery but a full overnight charge would last me until the evening, longer with a bit of good sun. I'm not sure I can get the same one this winter, but I'll do something similar. One day I'll double my batteries so I can easily get through the full day on a charge.
SenileOldGit
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The reason I criticised your response is because your first response to the OP (who is obviously not very knowledgeable about these things, which is why he is asking questions here) was:
"You do not need distribution network operator ( DNO ) permission if your system is below 3.6kwp per phase. However in all cases you are required to inform them within 28 days of any solar infrastructure that is grid tied
If you have battery systems, doing grid feedback , or have islanding facilities you must seek prior approval ."
None of that was relevant AT ALL because the OP is getting an OFF GRID inverter. So having battery systems is irrelevant, because his inverter is off grid. Doing grid feedback is irrevelant, because his inverter is OFF GRID. Having islanding facilities is irrelevant for the same reason. He doesn't need DNO permission even if he has 20kwp per phase, since his inverter is off grid and cannot export anything back to the grid.
Imagine coming here with your first question and getting an answer that completely confuses you because it ignores the most basic facts about your setup...
I recently joined this forum for pretty much exactly this requirement, and have been dismayed at the misinformation (here and on the wider internet) about installing an off grid system in the UK. It's incomprehensible why people are saying things like this. Are they deliberately trying to confuse us? Are they paid by the electricity companies to spread misinformation?
After spending days researching this, I have concluded that I should not get DNO permission, and I should just buy a battery charger (such as the EG4 chargeverter) on a timer to top up the batteries in winter with Economy7, as the battery charger is just an appliance, similar to the 3kW heater the previous poster mentioned.
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