Dillsue

Whatever export limit the DNO sets you can always have a much bigger inverter and array and just export limit via G99+G100.

The battery wouldn't care if the inverter is 5 or 100m away but your wallet would when you buy the connecting cable. Our battery comes with 50mm2 cables for a 1.5m run

When we added a second set of PV a few years ago the plan was to have generation all day long by spreading the panels from SE to NW as we didn't have a battery. The NW array does virtually nothing in the winter but does keep the generation going to cook tea for maybe 6 months of the year. Now we have a battery charged off cheap overnight eleccy we let all the PV run to the grid and grab the Octopus export payments. Without a battery you'd need quite a sizeable array correctly orientated to power you through early morning and evening without drawing much from the grid, even in summer. PVGIS gives your hourly generation forecasts so you can have a play and model the panels you could install versus the house load through the day. Or get a battery.

Not sure if all inverters have them but I'm pretty sure Solaredge inverters have a built in RCD so even with a faulty grid loss shutdown the in built RCD should take care of anyone zapping themselves.

If it's an armoured cable and you have a route along a fence, why not clip it to the fence rails or tywrap it to a strand of fencing wire.

The 2 arrays don't have to be operating near maximum. With the figures I posted one array can be near max and the other at 50% for the inverter to start clipping output. I dont know the difference in price between a single and dual MPPT inverter but would guess its not much. Going for a dual input removes this issue entirely and would then avoid clipping for the life of the system

If your getting around 4p/unit with octopus it's SEG. If your talking about the 12p/unit deal that's a power purchase agreement. The former is gov regulated but the latter is an unregulated contract between you and whoever wants to buy your export.

I don't think the network map has to be green to get an export consent. SPENs "heat map" for our area is all red but we had no problem getting a 7.5kw limit. I think the capacity shown on their heat maps might be for larger generator connections....maybe a solar farm or an AD plant. Don't let it put you off if its red!

Just re read it and understand how they've split the arrays....as you say. I'm not sure how valid that paper is with today's kit. The paper seems to be from 2013 when panels were a fraction of the wattage/current than they are today. For a single inverter/MPPT system they say the E/W arrays must be wired in parallel which will significantly increase the current over that of a single E or W array. Back in 2013 the combined current would still be quite low and likely manageable by a single inverter/MPPT. With modern panels the current is significantly higher than those from 2013. Put 2 modern arrays in parallel and you could go over a single inverter/MPPT limit?? With figures plucked off the Web you've got a max 15A DC input for a solis 5kw inverter and Longi 450watt panels with a max 11A output. Put 2 longi strings in parallel and I'd be pretty sure your going to exceed the inverters 15A input limit??

Maybe Im missing something but the Fronious write up is comparing output of 2 E-W arrays each with different panels, mounted at differing inclinations and facing different directions?? Hard to see how you'd get a meaningful comparison of them wired to a single inverter VS 2 separate inverters??

We run ours on Octopus Go currently 5 hours at 8.5p and the rest at 32p. The whole official drive to heat pumps is utter bollocks. We've just had our EPC redone pre sale and the asessor told me that heat pumps can be less efficient than a gas boiler and our EPC reflects this. Apparently within SAP if you enter the heating as a heat pump with radiators it defaults to 55 degree flow temp with drops the HP efficiency. Having explained our over sized radiators and max 34 degree flow temp he just shrugged his shoulders! The EPC came through with an estimated 28000 kwh needed for heating versus the actual 3800 we used last winter to keep the house at 20/21 degrees! It's bonkers

Does the HP always start up in heating mode before it switches to cooling so at the start of every cycle they'll be a short period of heating.....circulating pump running to establish flow is always done in heating mode??

Don't think you were napping....... MIs were an option til Simon mentioned connecting to an inverter

If you're looking to hook up panels to the inverters second MPPT dont use micro inverters as they push out AC whereas your inverter is needing a DC input. Optimisers is what you want if you're connecting to the MPPT input. I don't know how much Tigo optimisers are but I beleive you can use solaredge optimisers with any inverter if you turn off the safe shutdown function with a Solaredge optimiser Key. You can pick up SE optimisers off eBay very cheaply if youre prepared to wait. Last time I looked the Key is about £80

Does a mounting system need to be MCS certified? The only thing listed on our MCS cert from a 2015 FIT system is the panels themselves, not even the inverter is listed let alone any mounting.

I think there's lots of inverters that allow 100% over sizing of the DC input compared to the inverter rating....our Solaredge certainly does. If you're looking to max out year round generation then maybe look for inverters that will allow more than 46% oversizing??

Anyone can put a G99 application in...you, designer, installer.

That's my understanding of how the DNOs operate. Our second system, sat in parallel to an older FIT system, had 8.5kw of panels but SPEN were only interested in the additional inverters rating that was much lower than the panels rating.

The inverter is what connects to the grid so DNOs would want to and do regulate inverters and any generator connected to their system. Where have you heard DNOs are interested in panel capacity??

If you've got 2 single phase supplies to the HP then you can use a single 4 pole isolator. I ran our data/control cables through the wall tie wrapped out of sight to the outside of the return pipe insulation. The mains supply came via a surface mounted SWA cable

How is any other cabling being routed in and around the insulation??

Standard leakage current trip is 30mA so what have you increased it to?

Be conscious that you can have existing leakage current that's below the trip threshold so the protection doesnt trip and it's only a very minor change in the fault, or a small additional fault, that cause the protection to trip. If it only happens with the unit warmer than usual then a breakdown of insulation within cabling/components is quite plausible but difficult to find!! Maybe start with close visual inspection of all the mains cabling and components for any build up of dust/dirt/moisture. If you've got access to working spares then you could try swapping out components but having a spares kit is a bit of a rarity. Therma Vs come up on ebay from time to time for peanuts so that maybe a source but you need to know and trust the reason they are being sold

Don't forget that earth leakage detection and tripping is a secondary safety feature and if Joe bloggs is plugging into system that isn't safe it's not because he doesn't have bi directional earth leakage detection.

The article doesn't really comment on specific safety concerns it just says that PIS doesn't comply with current regs and needs to be safe.