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Yes, that is irritating with the SMA inverters. There is no reason in principle the firmware could not limit the current as well as the power. It would be useful in this country as de facto we are mostly at 240V rather than 230V. A 4kW power limit (FIT) combined with a 16A current limit (G83) would be ideal. Any manufacturers listening?
 
Absolutely. FITs are based on TIC which totally depends on output from the inverter instead of the amount of panels fitted on the roof.

Isn't it the other way around -

TIC = Total Installed Capacity which would be the total capacity of the installed solar panels
DNC = Declared Net Capacity which would be the maximum output of the inverter

The FITs are based on TIC, the need for prior DNO approval is based on the DNC
 
If FiT's are based on TIC then why does the British Gas FiT form I filled in lack TIC and only asks for DNC?
As it happens, mine was entered as 4kWp as that's what my MCS certificate said for DNC. My system is 16 x 250W panels and a 3.68kW inverter.
 
If FiT's are based on TIC then why does the British Gas FiT form I filled in lack TIC and only asks for DNC?

I don't know but if you look at the legal document TedM posted the link to earlier (http://www.decc.gov.uk/assets/decc/...tions-of-electricity-supply-licences-2011.pdf), which is the official document on the matter it says (page 5):

"Solar photovoltaic with total installed capacity of 4kW or less, where attached to or wired to provide electricity to a building which is already occupied"
 
We have been here before. TIC has a statutory definition, for example here:
http://www.decc.gov.uk/assets/decc/...0100331172153_e_@@_fitlicencemodification.pdf

“Total Installed Capacity” means the maximum capacity at which an Eligible
Installation could be operated for a sustained period
without causing damage to it (assuming the Eligible Lowcarbon
Energy Source was available to it without
interruption), a declaration of which is submitted as part
of the processes of ROO-FIT Accreditation and MCScertified
Registration;

Translating and simplifying, it means TIC = the maximum continuous output of the inverter, or if the kWp of the panels is less than the maximum continuous output of the inverter then TIC = the kWp of the panels installed (assuming they could all receive maximum sun at once).

If the British Gas form only asks for DNC then it is because they are dozy. However in almost 100% of cases for simple solar pv then TIC = DNC so in effect it is not an issue.

And incidentally, although the statutory definition in the legislation says we submit TIC as part of MCS registration, it is only via telepathy, because the MCS registration process asks for DNC!

Regards
Bruce
 
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So can I install 15x245w= 3.67 kw on a sma 4000 or 4kw of panels on a sma 3.6tl..???
 
Yes, although I would advise caution how you present it because there are many in the business on all sides who would not recognise the legislation if they tripped over it.
 
The unfortunate position is that OFGEM drafted legislation using terms (TIC and DNC) that apply to (and make sense in) much larger power generating scenarios but which are rather meaningless for microgeneration without further clarification.

But TIC and DNC are now pretty much obsolete terms for large power stations and have been replaced with others, such as RC, TEC and CEC.

Most of this is explained here: National Grid - SYS 2006 - Generation - Generation Terminology

I've tried in the past to get OFGEM to produce more sensible definitions for TIC and DNC, that can be directly applied to PV and other microgeneration systems, but they have simply refused.
 
Yes, that is irritating with the SMA inverters. There is no reason in principle the firmware could not limit the current as well as the power. It would be useful in this country as de facto we are mostly at 240V rather than 230V. A 4kW power limit (FIT) combined with a 16A current limit (G83) would be ideal. Any manufacturers listening?

To comment on my own post, I note that the Solar Edge SE4000 16A version does just that: max output 4kW, max current 16A.
 
I'd be interested to hear how you get on with that.

Installing more than 4kWp of panels has always bothered me for this very reason. Is it something that you have done a lot?
no worries, I shall be reporting back, and probably discussing it in the pub shortly.

We've installed a fair number of these systems, probably around 15-20 of them, so if the company doesn't alter it's position we won't be taking their decision at face value and will be pursuing it through the courts if needed.

I took our professional indemnity insurance last year after I realised how many of these installations we were doing, so we ought to be covered by that if the worst happened, which I believe ought to also mean that it would end up being the electricty company vs both us and our insurers in court which ought to help with any legal costs if it comes to that.

TBH, I've always thought this would end up with someone having to take this to court at some stage to get a binding legal precedent set since OFGEM seemed reluctant to issue guidance on it. I think OFGEM probably realise they're in a pretty difficult position here legally, and any advice they issued could come back to bite them if a court disagreed with them.

Still, hopefully they'll just back down tomorrow after my email.

I also notice Scottish Power have started asking specifically for the details of the panels, number of panels etc which is a little suspicious.
 

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