Off grid array - legals & safety

[Solarexploits]

Ok, so I already have several off grid panels myself operating satisfactorily with a lead acid battery bank, this has been used as a temporary installation & test bed, it is far from a "formal" installation, mine mainly runs via a couple of extension leads apart from the lighting which has been removed from the consumer unit & runs via a separate RCD

 

A friend has now asked me to help him with a similar off grid installation, but this is definitely going to be permanent & become a fixture within his house. We are obviously somewhat more concerned with legal/insurance/electrical regs The inverter will be a 48V hybrid unit, only connection to the mains will be for occasional charging if batteries have got too low

 

What is required in terms of switching/fuses between battery bank & inverter? & what is required from the inverter to the mains circuits, he's already assumed he'll need a 2nd consumer unit/RCD's for any circuits he wants to transfer from existing. What is needed in terms of isolation in either case - as this is all off grid, is there any requirement to notify authorities/insurers etc.

 

If you mention specific types of switches/isolaters etc then any links would be useful to ensure we're looking at the right equipment

[Dillsue]

At the time you "occasionally" connect to the grid to charge flat batteries/deal with a failed inverter, its a grid connected system so needs G98/G99 compliance.

 

I think the wiring regs apply to surprisingly low voltages which would include your off grid PV output if its series wired. Youve stated theres an occaisional grid connection so any of that wiring falls under the regs

 

TBH its one thing installing stuff for yourself when theres a bit of uncertainty, but doing it for someone else is a different kettle of fish.

 

 

[Solarexploits]

On 20/07/2022 at 18:55, Dillsue said:

At the time you "occasionally" connect to the grid to charge flat batteries/deal with a failed inverter, its a grid connected system so needs G98/G99 compliance.

 

I think the wiring regs apply to surprisingly low voltages which would include your off grid PV output if its series wired. Youve stated theres an occaisional grid connection so any of that wiring falls under the regs

 

TBH its one thing installing stuff for yourself when theres a bit of uncertainty, but doing it for someone else is a different kettle of fish.

 

Had a quick look at G98/99, so far as I can see it only refers to grid tied systems - charging a battery doesn't in any way connect the off grid system to the grid any more than using a battery charger to charge batteries would surely?

[Nickfromwales]

52 minutes ago, Solarexploits said:

 

Had a quick look at G98/99, so far as I can see it only refers to grid tied systems - charging a battery doesn't in any way connect the off grid system to the grid any more than using a battery charger to charge batteries would surely?

It’s the event ( albeit unlikely ) of equipment failure that were supposed to factor in, which is where / why these kinds of regs reside. 
I’d argue that you’re correct, eg if the battery charger has crocodile clips vs crimped eyelets which are bolted permanently to the batteries then it’s no worse than charging a vehicle. 
 

The fact that there’s a 13a plug on these domestic chargers with exposed metal ( male ) connections means there is absolutely zero chance of connecting to a battery snd getting 230VAC back out the other side. Would never get certified if so. Simples. 

Edited July 21, 2022 by Nickfromwales

[Nickfromwales]

Just fit grid-tied hybrid inverters and dial them down to zero export. Declare and forget. 

[Dillsue]

13 hours ago, Solarexploits said:

 

Had a quick look at G98/99, so far as I can see it only refers to grid tied systems - charging a battery doesn't in any way connect the off grid system to the grid any more than using a battery charger to charge batteries would surely?

I know virtually zilch about battery charging systems so Ill take your word for that. Whats the plan for a failed inverter?

If your mate is going to keep a grid connection for battery charging and pay the standing charge then why have the system off grid? You might have to pay a G99 fee to do things legit but its a one off payment thats probably quite small in relation to what hes likely to pay for his PV just now.

[Solarexploits]

14 minutes ago, Dillsue said:

I know virtually zilch about battery charging systems so Ill take your word for that. Whats the plan for a failed inverter?

If your mate is going to keep a grid connection for battery charging and pay the standing charge then why have the system off grid? You might have to pay a G99 fee to do things legit but its a one off payment thats probably quite small in relation to what hes likely to pay for his PV just now.

Sorry, perhaps I didn't make it clear in the original post, he has no intention anymore than I do of being completely off grid, in the UK I really don't think it works unless you're building or modifying a place from scratch with that as the aim, even then if you want what we've come to expect as normal living, you'd need a huge array & battery bank & probably wind & a generator as backup, costs would be huge

 

No idea how much a G99 fee is, but you then get into the whole business of  electrician's inspections & sign offs, local authority notification, MCS if it's a full supplier install etc etc & with no FIT payments & the alternative being pitifully low, just doesn't seem worth all the hassle of being tied to the grid with associated formalities

 

What I've done & what he's looking at are SH panels, we have 20 on the way, some of which top my system up & the rest for him, a relatively cheap hybrid inverter 4000/5000W & I have access to SH lead acid solar batteries dated only last year at very sensible money, I set my system up (currently 10 x 310W panels, but room for more) for around £1400, he'll be looking at a little more for his, but with the way energy prices are going that should pay back within a couple of years or so

 

We're perfectly capable of doing the work, but don't have the formal qualifications, just don't want to do something that would come back to bite him

[kommando]

As long as the system eg the panels and the batteries are used within a circuit completely separate from the grid connected circuits then you do not need G98/G99 application/approval. However as soon a any part feeds wiring that is also connected to the grid even if temporarily then depending on the size of the generation you will need G98/G99.

 

As an example I have a small generator for use during power cuts, it has a dedicated input feeding a 3 position rotary isolation switch Grid/Off/Generator on the main feed between the meter out and into the consumer unit. As the middle position is Off there is no possibility of the generator feeding the grid whilst moving the switch from Grid to Gen or back. The local DNO changed a Transformer recently and inspected the setup and allowed me to run the generator for the 2 days they cut me off.

[joe90]

On 20/07/2022 at 18:03, Solarexploits said:

only connection to the mains will be for occasional charging if batteries have got too low

Will that be by connecting crocodile clips as per @Nickfromwales point above? 
 

14 hours ago, Nickfromwales said:

The fact that there’s a 13a plug on these domestic chargers with exposed metal ( male ) connections means there is absolutely zero chance of connecting to a battery snd getting 230VAC back out the other side. Would never get certified if so.

 

20 minutes ago, kommando said:

a dedicated input feeding a 3 position rotary isolation switch Grid/Off/Generator

Change to. Battery charger/off/PV

[SteamyTea]

If, for arguements sake, this off grid supplies a circuit or two in the house i.e. lights and DHW.

There needs to be clears signs saying which circuits could be live, even when the main consumer unit is off.

There are probably regulations for this already.

 

[TonyT]

you get labels saying this equipment is fed from 2 supplies etc.

stick it with the consumer unit with the other labels that are ignored such as testing rcd's etc

[Dillsue]

3 hours ago, Solarexploits said:

No idea how much a G99 fee is, but you then get into the whole business of  electrician's inspections & sign offs, local authority notification, MCS if it's a full supplier install etc etc & with no FIT payments & the alternative being pitifully low, just doesn't seem worth all the hassle of being tied to the grid with associated formalities

Technically youll likely need an electrical inspection even If off grid- see previous comments. For grid tie theres-No local authority involvement unless you want it. No MCS unless you want it.  Unless you want something else the only additional formality for grid tie is G99 at circa £300. Im sure someone posted that their DNO processed a G99 for free??

[kommando]

A G99 Fastrack is possibly free as its just a G98 with extra detail to cover the battery bank as a generator and how the system ensures even with full sun and a full bank of batteries only 3.68kw can be exported.

[Ronski]

I've just had a G99 DNO approval for additional 5kW PV & 4.4(0)kW Battery, no fee required, DNO is UK Power Networks.

 

 

[Solarexploits]

On 26/07/2022 at 08:25, Ronski said:

I've just had a G99 DNO approval for additional 5kW PV & 4.4(0)kW Battery, no fee required, DNO is UK Power Networks.

 

 

So what inspections/certification are carried out for the G99 approval - sorry, I know zero about this, my off grid system is completely off grid, can never feed back to the mains, my grid tie system was an old MCS install back in 2011, so I had no involvement in anything other than paying for it.

If he decided to go grid tied, but not bother with getting anything back for anything exported does that make the process simpler & is there any reason he can't use the second hand panels we already have?

Are ther any specific mounting requirements for the panels as most of it would go on 2 separate (different heights) flat rooves & we were intending to make our own mounts?

[Dillsue]

1 hour ago, Solarexploits said:

So what inspections/certification are carried out for the G99 approval

You tell the DNO what you want to export to the grid, and what equipment your going to use to limit the export to what youre applying for, the DNO then says yeah or yeah but upgrades are required. Once youve got approval and done the work send the DNO the completed commissioning form and a simple drawing showing how things are connected.

 

If youre mate keeps export under 16amp then he just notifies the DNO via a G98 notification.

 

Getting paid for export is a differnt set of certification/approvals from getting permission to connect to the grid.

[Solarexploits]

3 hours ago, Dillsue said:

You tell the DNO what you want to export to the grid, and what equipment your going to use to limit the export to what youre applying for, the DNO then says yeah or yeah but upgrades are required. Once youve got approval and done the work send the DNO the completed commissioning form and a simple drawing showing how things are connected.

 

If youre mate keeps export under 16amp then he just notifies the DNO via a G98 notification.

 

Getting paid for export is a differnt set of certification/approvals from getting permission to connect to the grid.

Is it worth going thro' the extra hassle to export, I believe you get paid peanuts now for anything going back to the grid?

Where do I get the G98 application from & can the commissioning be confirmed by any properly qualified sparky?

[Dillsue]

3 hours ago, Solarexploits said:

Is it worth going thro' the extra hassle to export, I believe you get paid peanuts now for anything going back to the grid?

Where do I get the G98 application from & can the commissioning be confirmed by any properly qualified sparky?

If your mate wants to be grid tied then its no problem exporting if he keeps export under 16amp/3.68kw. Any export just goes into the grid for someone else to use. If you want paying for any export you need a professionally installed system almost certainly using new parts and costing ££££££

G98 is a notification not an application form, if your max export is 16amp or less. You notify with a G98 and apply for permission with a G99 application. Work out who your DNO is and Google G98+their name to get the form.

A spark can sign off the install

Edited July 28, 2022 by Dillsue

[Solarexploits]

19 hours ago, Dillsue said:

If your mate wants to be grid tied then its no problem exporting if he keeps export under 16amp/3.68kw. Any export just goes into the grid for someone else to use. If you want paying for any export you need a professionally installed system almost certainly using new parts and costing ££££££

G98 is a notification not an application form, if your max export is 16amp or less. You notify with a G98 and apply for permission with a G99 application. Work out who your DNO is and Google G98+their name to get the form.

A spark can sign off the install

Ok, I think for him, that is going to be the safest & most cost effective option (might also save me a load of unpaid work!)

 

So, just to clarify, he's with UK Power Networks, so I google to get the G98 form, we fill it out & send it in once we're ready, when do we send in the G99 & do we have to wait for approval? & once ready for operation a sparky signs it off (I have someone for that) & as long as he won't export more than 16A (is that regarded as 3840W,4kW or what?) & that's it, no inspection of anything other than by the sparky? It just sounds far too simple, I thought being grid tied involved loads of paperwork???

[Dillsue]

No!!! He fills in either a G98 OR G99, not both.

 

If he keeps his export below 16amp/3.68kw and uses a G98 certified inverter, then he notifies UKPN that he has solar PV that has 16amp limited export. Its a G98 notification, not an application. The notification goes in after the system is connected to the grid

 

If he wants to export more than 16amps because he has more to export OR he doesnt use a G98 certified inverter, then he has to ask permission via a G99 application. The G99 goes in before the system is connected to the grid and you need approval before you connect to the grid

 

The spark signs off the install/test paperwork in either case. Unless theres extra complexitiy added to limit export via G100 theres not normally a DNO inspection, AFAIK

 

G98 is straight forward and G99 can be if you keep things simple and sensible, in my experience.

[Ferdinand]

On 28/07/2022 at 14:08, Solarexploits said:

Is it worth going thro' the extra hassle to export, I believe you get paid peanuts now for anything going back to the grid?

Where do I get the G98 application from & can the commissioning be confirmed by any properly qualified sparky?

 

Octopussy has at least one tariff that gives you around 8p.

 

And there may be one that gives you more.

 

If you have things like e-cars and house batteries.

[Ronski]

I've just done a G99 application with UK Power Networks, it was all very straight forward. I'm at work otherwise I'd attach the form.

 

If your only installing 3680w  of generation (inverter rating), then you only need to notify after installation within 30 days with G98. If more than 3.68kw then you need to fill in form G99 before you install, once approved you get six months to install, but you have to notify them within 30 days of commissioning.

 

The one thing that worries me is what's going to happen to export prices in the future, if they go up, which I think they will , then without an MCS install we could lose out. I already have an MCS install so wonder if I'd be OK when I self install another array.

[Dillsue]

If youve already got G99 approval then that export capacity is in the bag for life, so no worries on the DNO front.

 

MCS is a bit trickier. Someone posted recently that MCS arent the only accreditation scheme that qualify you for export payments?? I think that over time with a drive for greener generation you may find companies will be less picky as to which micro generators they buy from and it maybe that you pay a small inspection fee to check youve actually got PV/wind/water turbine and theyll buy your export??

 

Theres also at least one company advertising PV kits for self install that will do MCS commission and certification if you buy and install their kit. Way cheaper way of getting MCS accreditation.

[Ronski]

@SolarexploitsG99 form attached for UK Power Networks

 

@Dillsue Can you let me know which company that is please - I did  find one on Ebay advertising the option of MCS sign off for £345. I already have an MCS system installed some years ago, so wonder if I can get away with that when I add an additional array and batteries. I think the export payments will increase as the market matures - there's already rumblings in the main stream press regarding the low amount most are paid.

g99-form-a1.1.docx

[Dillsue]

29 minutes ago, Ronski said:

Can you let me know which company that is please - I did  find one on Ebay advertising the option of MCS sign off for £345.

Solar energy store on ebay