solar pv quote

asturdy2

just had a quote for solar pv




12 lg300n1c panels
power one pvi3.6 inverter


£5995 for 3.6kw system


thought id be able to get 16 panels on but surveyor says to stick to the mcs regs you have to leave a 50 cm gap from the edge of the roof. Similar properties have 16 panels on but he says they are against the regs.


Any thoughts please ?


Iam getting another quote tomorrow.

tunnel

asturdy2 wrote: »

just had a quote for solar pv




12 lg300n1c panels
power one pvi3.6 inverter


£5995 for 3.6kw system


thought id be able to get 16 panels on but surveyor says to stick to the mcs regs you have to leave a 50 cm gap from the edge of the roof. Similar properties have 16 panels on but he says they are against the regs.


Any thoughts please ?


Iam getting another quote tomorrow.

The surveyor is wrong, you should leave a 30cm gap from the edges and if you were pushed for room you could always go for sunpower or benQ panels at 327W, 12 of these would give you a 3.92kWp system.


Do as you say, get some more quotes


By the way, the price isn't far off, you should be looking at that price for a 4kWp system though.


Just post back on here with your quotes if you're unsure


Tunnel

asturdy2

The roof is 7.5 metres long, I thought I would get 16 at a push but looking from ground level he thought 14, Anyway he went away to do the quote and came back with 12 !

tunnel

As a rule of thumb most panels are 1.6m x 1m. Could they not go on in landscape(horizontal) rather than portrait(vertical). You'd need your roof to be 4.6m long for that though(16 panels).
Really do need to have someone to measure it up rather than look from the ground to get exact measurements

asturdy2

just got this off the mcs website :


Unless specifically designed to do so, systems should be kept away from the roof perimeter. For a






domestic roof, a suitable minimum clearance zone is around 40-50cm.


The requirement to keep an arrays away from a the edge of a roof is suggested because: wind loads


are higher in the edge zones; keeping edge zones clear facilitates better access for maintenance


and fire services; taking arrays close to the roof edge may adversely affect rain drainage routes; and


when retrofitting systems, there is the potential for damage to ridge, hip, valley or eaves details.




Note – on many roofs a 50cm gap from the edge will still mean that PV modules are fitted in the


“Edge Zone” as defined in BS EN 1991-1 where higher pressure coefficients need to be implemented




due to the higher imposed wind loads.


guess the surveyor knows his stuff

tunnel

Maybe, maybe not. I'm only going on what my installer went on which at the time was 30cm. Its quite possible that the regs have been changed.


Even so, putting your panels in landscape would still mean 4 side by side, although they may not be as aesthetically pleasing, would still depend on the depth of your roof

asturdy2

also the generation figures were a tad optimistic,


3200 units generatated on a 3.6kw system on a 130 degree south west facing roof in Lancashire. PVGIS calculator gives between 2800 and 2900 depending on what you put in.

tunnel

I've just got 3200 for SW in Liverpool but without your location, pitch and Azimuth(SW is 45 deg) then no-one can be sure only you.


Ps Tried again for blackpool with SW and 45 Deg pitch and get 3330


Are you saying your just the wrong side of SW at 130 deg?

Martyn1981

'just for a laugh', I stuck a few pins in the PVGIS map too. Wasn't sure what 130 degree south west meant, so tried SW (+45d) and ~SE 130d from north (-50d), and also got figures of around 2,900 to 3,300 ....... until I got near the Blackburn, Burnley, Rochdale areas, and gen dropped to 2,800 or so.

So as tunnel says, it's really down to your specific location, as generation in that area is obviously quite variable.

Regarding panel sizes, 7.5m is a tight number. If you allow 20mm gap between panels, then 7 1,000mm panels will need 7.12m. That would still leave 200mm on each side, which is probably the minimum, and as you've found, maybe 500mm desired if wind lift is a concern. Distance from the top is particularly important, as the panels sit proud of the roof, perhaps 150mm in total, and may therefore be higher than the ridgeline, which would (I think) require planning permission. So usually leave about 300mm from the bottom edge of the ridge tiles.

So without being pedantic, you need to get an exact measure of your roof to see if you have any play room or not. Also panels vary a bit, eg LG's may be 1,000mm, whilst YingLi's may be 990mm (different models (as well as makes) will vary) and those 10mm*7 might make a difference. Some of mine are 1,050mm.

Mart.

asturdy2

we are in burnley, 130 degrees is the compass measurement i.e 50 degrees from south, my quick measurements of the roof from ground level is 7.5m by 5m. Pitch on the quote is down as 30 degrees. Got 2 more installers coming today, if we could get 14 lg 300 panels on making 4.2kw would that be ok as we are not dead on due south and would not generate that much. We also have a metal chimney on the south side of the house which would give some shading early morning especially this time of year, he thought it wasn't worth mitigating it with micro inverters.

EricMears

asturdy2 wrote: »

just got this off the mcs website :


Unless specifically designed to do so, systems should be kept away from the roof perimeter. For a



guess the surveyor knows his stuff

No, if the customer wants to fill their roof with panels he should be "specifically designing" a fixing method that would allow that. Any halfwit could suggest abandoning the project; Customers need solutions not warnings !