Mini Setup. Is is feasable?

...Ghost...

I want to get solar this year. Most likely 9 panels with battery on south facing roof.

First I would like to do a little DIY setup on my small shed roof. The roof is on a slight incline maybe 10 degrees and faces north. I should be able to fit 3 panels on it and am I right in thinking if I use a micro-inverter, I can basically just plug the panels into a socket in the shed, which is fed from the house CU?

The shed houses pond equipment which uses less than 200W. I would like the panels to run the equipment when the sun shines and the extra generation to go to the house.

Am I looking at this the right way and can anyone recommend a kit for this?

slave1

I don't think anyone on Boards can advice you to do that (plug the panels into a socket), it's possible but sketchy

...Ghost...

https://www.boards.ie/discussion/comment/120344962#Comment_120344962

If there is a sub-CU/panel in the shed, connecting the panels via the micro-inverter to the sub-CU would be the usual way to do this? Or of course directly to the main CU....

Deagol

And electrocute the first person who turns off the main switch in the CU not realising you're backfeeding 230vac into the circuit....

Please don't DIY it, potentially you'll end up with a dead family member / friend / contractor - and you'd be both civilly and criminally liable I think!

graememk

https://www.boards.ie/discussion/comment/120346101#Comment_120346101

Grid tied Microinverters are exactly the same as normal inverters with anti islanding, they shutdown if there is no grid detected. (As they have to match the phase of the grid to operate)

Also anyone touching the electrics should be doing safe isolating and proving dead before even touching anything as a matter of course.

...Ghost...

https://www.boards.ie/discussion/comment/120346101#Comment_120346101

Wouldn't it be a simple case of labelling on the main CU that there is a secondary solar source that needs to be isolated too? I thought the micro-inverter only works if the CU is powered on.

I was hoping to be pointed in the right direction on the best setup and recommended equipment. I'm not some white collar worker who's never held a tool. I've carried out competent electrical work at home on several projects. I'm a mechanical engineer and work with very high voltages every day. Because this is my first dive into solar, I preferred advice from those more familiar.

...Ghost...

https://www.boards.ie/discussion/comment/120346706#Comment_120346706

Thanks. That's helpful. I was under the impression that a micro-inverter with a small number of panels was a relatively safe way to begin my solar journey and build on my understanding. If the CU is powered down, the micro-inverter also powers down as it is on the consumer side and won't run unless it detects voltage from the CU vie the grid, correct?

Deagol

https://www.boards.ie/discussion/comment/120346706#Comment_120346706

Wasn't aware of that. But I'm assuming that shouldn't be the only protection on the circuit? i.e. should have the switch too? And your other point I'd say, sun is in when CU switch is off.. no ac from solar... prove dead. Sun comes out / sun rises.. power comes on?

graememk

No grid = no power from a grid tied Microinverter, sun or no sun

But yes to have an isolator on the solar side.

Shed CU, should be fine as long as the supply to it is good enough.

Labeling in the consumer unit is important too.

I think midsummer have the hoymiles microinverters.

2011

A few important points:

1) This work must be carried out by a Registered Electrical Contrator. It is a criminal offence for anyone else to "have a go at this".

Link: https://www.cru.ie/consumer-information/home-safety/electrical-works/

and

https://www.cru.ie/regulations-policy/safety/safety-compliance-and-enforcement/

"It is an offence to carry out restricted electrical or gas works while not registered or to falsely portray oneself to be registered. The penalties for both offences are set out in the Electricity Regulation Act 1999 (as amended). This includes a fine of up to €15,000 and/or imprisonment for up to 3 years."

2) People don't always do what they "should do".

A little knowlage is a dangerour thing.

bullit_dodger

https://www.boards.ie/discussion/comment/120346101#Comment_120346101

Actually that wouldn't likely happen. Most (all?) microinverters are powered by the AC not the DC side. So if you pull the power on the main consumer unit, then the microinverters would no longer be producing power irrespective of if the sun was shining or not. So no back feeding. It's the safety process that they have to stop that very scenario.

That said it's not like wiring a plug for a kettle here. You can do it safely, but you shouldn't be "a have a go hero" unless you have a good understanding of electrics. You'd need to also know the guage of the wire going back from your sub board to the main board or you could run the risk of overloading that wire. 5-6 Panels on the shed should be fine though (in general)

Afterthought: You'll still need a qualified spark to sign off on it as in theory you'll need a NC6 form submitted with ESB networks that your a microgeneration location.

...Ghost...

https://www.boards.ie/discussion/comment/120348079#Comment_120348079

That's good to know. I would only have 2 or 3 panels on the shed and production would be sub-optimal due to orientation. I have standard T&E running from the CU to the shed in conduit. I would likely swap this out for 4mm^2 armour, as I would later add 3 or 4 panels on the flat roof extension. I would only do that after upgrading my tails and CU and that's definitely a job for the sparks. I could do it, but I know when to stop and leave it to the professionals.

slave1

If going 4mmSWA may as well go 6 for future proofing, I can't remember the price difference

...Ghost...

https://www.boards.ie/discussion/comment/120350739#Comment_120350739

Very little price difference. 4mm is just easier to work with and I would be unable to get more than 6 panels on the shed and extension. So, that would be what....2-2.5kWp on the shared part of that circuit? The only benefit I can see of the bigger core would be lower resistance. The panels planned for the main roof would be on a separate run. Unless I am missing something?

slave1

4mm is fine so, I ran 4 and 6 for my arrays to cover any possible future endeavour e.g. ground mount