MCS - and how to move forward

[Robin Loft]

Dear Talk Electrician Forum. Having read with interest and learned from you much about the operational aspects of PV panels, inverters, diverters, car chargers I am encouraged to write to you about my intended system which is still in the planning phase.

I have the cash and desire to install a 23-26 panel system with a 8-9kW inverter, a diverter to a car charge point/battery 10-20kWh battery bank/ immersion element within a large thermal heat store (500ltr), plus of course our own domestic use and SEG. Depending upon calculations I might even go for something like Octopus’ agile or night rate scheme – wintertime especially. We are 2 persons living in a bungalow.

I am competent to fit the panels onto two adjacent new purpose-built ManCave extension roofs sloping at around 9degrees - but not so the remaining equipment. The roofs face south-west and are of fibreglass on strong OSB + joists. I am happy to accept panels at the same angle as the roof rather than mount them on cradles – I appreciate a small loss is likely in output. No shading.

My issue is with using solar companies and the stranglehold MCS appears to have on certification. My long-standing NICEIC electrician won’t do roof work and is not MCS registered. My local Council – York (building control) aren’t concerned as long as the electrician is qualified but my current power company EDF will only accept MCS certification for SEG.

I can get up to 15ppkWh from SEG but the added costs of MCS contractors leaves me sore – being an adopted Yorkshireman. I would much rather sit down with a qualified person (paid), design the system with her/him in its entirety, buy all the equipment, fit the roof panels myself, leaving the rest to a qualified electrician for fitting & commissioning.

The certification aspect seems to be the constraining issue.

My ask to the Forum is what suggestions would you have for me to move forward please?

Thank you – Robin from York



The not-essential-at-the-moment-matter is I wish to replace my 5 year old combi with an ASHP working within the thermal heat store system for both CH & Hot Water utilising cheaper rate electricity from the battery bank. But there is no urgency in this as yet.

 

[binky]

I am competent to fit the panels onto two adjacent new purpose-built ManCave extension roofs sloping at around 9degrees - but not so the remaining equipment. The roofs face south-west and are of fibreglass on strong OSB + joists. I am happy to accept panels at the same angle as the roof rather than mount them on cradles – I appreciate a small loss is likely in output. No shading.

There is no roof mounting system designed for this type of roof and cradles are only intended for upto 5deg pitch if I remember correctly, so you will have to get inventive on those roofs. The last time I encountered this problem, we firbreglassed over timber blocks so that we had something to screw into, then used standard roof hooks and rails and sealed over the screws/ roof hooks with sikaflex to prevent any water ingress into the wood.

My issue is with using solar companies and the stranglehold MCS appears to have on certification. My long-standing NICEIC electrician won’t do roof work and is not MCS registered. My local Council – York (building control) aren’t concerned as long as the electrician is qualified but my current power company EDF will only accept MCS certification for SEG.

if you do the roof, your sparky can do the rest, it's not that hard.

I can get up to 15ppkWh from SEG but the added costs of MCS contractors leaves me sore – being an adopted Yorkshireman. I would much rather sit down with a qualified person (paid), design the system with her/him in its entirety, buy all the equipment, fit the roof panels myself, leaving the rest to a qualified electrician for fitting & commissioning.

Ok you may lose the SEG from not getting MCS cert, but as energy is being charged at 40p per kWh (obviously not the off peak rate) do you really want it anyway? The £ks charged for MCS adds up to a lot of SEG payments.

The certification aspect seems to be the constraining issue.

My ask to the Forum is what suggestions would you have for me to move forward please?

do it yourself with your sparky

 

[Robin Loft]

There is no roof mounting system designed for this type of roof and cradles are only intended for upto 5deg pitch if I remember correctly, so you will have to get inventive on those roofs. The last time I encountered this problem, we firbreglassed over timber blocks so that we had something to screw into, then used standard roof hooks and rails and sealed over the screws/ roof hooks with sikaflex to prevent any water ingress into the wood.

if you do the roof, your sparky can do the rest, it's not that hard.

Ok you may lose the SEG from not getting MCS cert, but as energy is being charged at 40p per kWh (obviously not the off peak rate) do you really want it anyway? The £ks charged for MCS adds up to a lot of SEG payments.

do it yourself with your sparky

Thank you Binky. Our specialist roofing chappie did suggest as much so as not to pierce the main roofs.
As far as the SEG is concerned I see your point. From my Yorksher perspective I'd rather advertise to our neighbours come and get free electric for your car when we have surpluses in summer!
Take care, Robin

 

[binky]

Thank you Binky. Our specialist roofing chappie did suggest as much so as not to pierce the main roofs.
As far as the SEG is concerned I see your point. From my Yorksher perspective I'd rather advertise to our neighbours come and get free electric for your car when we have surpluses in summer!
Take care, Robin

nothing to stop you selling them spare leccy

 

[bladerunnerpv]

Hi Robin
Can't comment on MCS, but the inverter size feels a bit small for the no. of panels.
How many kwh pa are you using, it feels like a big installation for 2 ppl?

 

[Robin Loft]

Thank you for responding Blade runner. Yes it is a large installation for just the two of us in a very well insulated semi-detached bungalow.
However, I've looked at the future proofing aspects. Namely CH from the thermal store and for when we get an EV& ASHP; both within 2 years. In midwinter we won't produce sufficient power to run everything, yet in summer we'll have an abundance of juice - hence the SEG.
The issue as I understand it is the certification; is there an alternative to using MCS accredited fitting firms?
Cheers, Robin

 

[Robin Loft]

Thank you for responding Blade runner. Yes it is a large installation for just the two of us in a very well insulated semi-detached bungalow.
However, I've looked at the future proofing aspects. Namely CH from the thermal store and for when we get an EV& ASHP; both within 2 years. In midwinter we won't produce sufficient power to run everything, yet in summer we'll have an abundance of juice - hence the SEG.
The issue as I understand it is the certification; is there an alternative to using MCS accredited fitting firms?
Cheers, Robin

I'll relook at the inverter sizing too.

 

[bladerunnerpv]

Hi, sorry, can't comment on MCS, other than to say from reading forum that it seems essential if exporting to grid.

If you're intending to export a lot you'd be wise to contact your DNO in advance and check how much they will let u export.

All have to allow 16A/3.6kW, more than that is by your DNOs agreement, which may not be given, depends on what ur installing. Recommend you look up G99 G100 etc and poss give them a call or email to enquire, explain what you're aiming to do.

It can take several months apparently after submitting Gxx paperwork for a Y/N answer.

 

[gustaff]

You can use these for attaching the rails although you do need to know where the joists are.
https://www.solartradesales.co.uk/schletter-fixing-kit-corr-roofs-10x200-klicktop?cat=9597
Locked to prevent being resurrected (again)