So my g99 application was refused, (im in the Uk) they said i can only connect 3.6kw onto my single phase line and i can only have a 4kw battery installed which must be set to zero export. 4kw? What a joke thst wont power my house for more than 2 hours!
They did however say i can connect the multiplus II 10kva inverter to the grid if i get a 3 phase upgrade.
So i asked if i would need 3 inverters, and they said no, i would only need to connect the inverter onto one of the 3 phases, and they said if i use my current single phase supply with the multiplus, theres a risk the voltage could rise and cause fires. I said i wasnt planning to export anything anyway, but that didnt matter to them.
I tried questioning how using a single phase from my utility pole can cause voltage rises while using a single phase from a 3 phase installation is safe, even though the two other phases are unused. Is this not electrically the same as my current single phase line?
They never answered that last question.
Im on a 60A head fuse right now, and i have been given the 3phase quotation, and it states i would be getting 3 x 60A fuses, so it has nothing to do with the supply cable or current.
Sorry to hear mate the issue is your looped supply, I know some distros are un-looping customers at the distros own expense so this could be a route that you use to un-loop the other property, is this an option? But your tenant will have to pay standing charges after.
I know it’s not what you want but go back to them and ask them if it’s in-looped can you install it on the single phase line hope this can help you get it sorted.
They dont know that its a looped supply, no one has come to inspect the current wiring, it not on any documents either as i wired the whole property myself. They seem to say its because the invert could cause voltsge to rise on a single phase, but now im thinking it could be that they want me to connect the victrom onto one of the proposed 3 phases and the 3.6kw array on another, but if i did that, the 3.6kw array cant charge my batteries as it does when connected to ac1 out of the multiplus.
Oh wow the network must be in a state if a new single phase isn’t going to sort it my guess is that the load is going to cause a voltage drop in turn the sub generator will ramp up and depending where you are on the line ie person closest to the sub generator will get massive spikes which if over 256volts the DNO has to rectify at there own cost. Oh so did you link the properties I thought it was the DNO.
So they only letting you export 3odd kW per phase if you had 3phase? Only one system that I can think of comes to mind but really doesn’t help you with all that you have spent already, getting the solar DC into the system rather thank AC may get you additional capacity not sure worth asking though so you are not shelling out for a new product.
Their reasonings are sounding for like a money making excuse now. I have just had another email from the dno, with a lame reason why i need 3 phase, this is it:
“It is the single phase cable that would be the issue, the new 3 phase cable is a thicker and bigger cable that is capable of taking the extra load. We would provide you with 3 x 60amp fuses providing you a capacity of 41.4KVA and you would need to have a 3 phase meter installed. Additional you would need your electrician to upgrade your consumer unit to a 3 phase unit.”
So basically the reason is needing a “thicker cable”
But each cable will have a 60 amp fuse, so whats wrong with my existing cable that also has a 60 amp fuse fitted ? Isnt it the fuse rating that matters here, not the cable thickness?
They continue to say i need a 3 phase consumer unit, so if thats the case, by loads would be split between the 3 phases, so if the inverter is connected to only one phase, ill only be able to run a third of my loads for free while the loads on the other two phases would run up a bill! This is not what i want, i want all loads running off the inverter to avoid using grid power as much as possible.
So this proposal would not work in my favor not to mention a probable £3k cost for this to be installed.
I think you may misunderstand. The DNO probably refers to the max inverter size attached to the storage propsed 4kW + 3.68kW existing PV making a total 7.68kW of power generators they will safely allow on a small 60A supply in your case. What you asked for is 8kW + 3.68kW. They will also be taking into accout future capacity for EV chargers and heat pumps in the bigger scheme of things and impact on the local transformers when making decisions. Maybe propose to set a G98 code, which should turn the system into a compliant 3.68kW unit. PS - Feeding in excess to the DNO supply should also not be confused with getting power from PV and batteries to you household loads, which is done through synchronizing feeding in.
In all fairness to DNOs, a G99 application and their feedback / approval should always preceed any equipment purchase as you just discovered he hard way.
@ejrossouw has a point the application factors existing PV, as said ask them if you get rid of the PV ie taking it DC you are only technically asking for 4.32kW which may allow the inverter to be installed.
That will require additional equipment but a lot less expensive than 3 phase, issue by doing this is you lose 3.68kW AC capacity but gain efficiency of DC to DC ask the question if the AC solar goes would you then have the capacity to install the inve
The whole idea was to reduce my enery bill to a bare minimum, youd think this should be supported in our energy crisis and "green"agenda, also the idea is to do it cheaply to make it worh while, or else theres no point in having done this project if it bately decreases my energy bills.
What i dont understand is, why would i need 3 phase, with only one inverter. Im on a 60A fuse which means i have 13kw of grid power, but if thats the issue, why cant they simply upgrade the single phase cable and give me a 100A fuse giving me 23kw, surely that would be enough.
Many people have the same ambitions, but the UK infrastructure is just not in place and will still take years to catch up. My last advice is to engage directly, via phonecall, with the DNO decision maker (engineer) dealing with your application as it definitely made a difference for my DIY customers when they got stuck.
Tbh this is getting too stressful gor me and knowing ill be facing a 4 figure bill, which would take even longer for breaking even, i just cant be doing with it.
Im going to keep the inverter off grid with a manual change over switch as it currently is, its working just fine that way. Given the sunny days weve had recently, i havnt used any grid power for nearly 2 weeks.