How the solar cuts out in a power cut

graememk

https://www.boards.ie/discussion/comment/121618074#Comment_121618074

Then you have the grid tie at source.. or bring the 3 phase to where you want to go.

_Brian

https://www.boards.ie/discussion/comment/121618148#Comment_121618148

Ok.

So in theory I’d have a grid tie inverter at the generation site and it would have the capacity to react and cut power if the mains was off.

graememk

https://www.boards.ie/discussion/comment/121618197#Comment_121618197

Yeah, no issue at all. It's electricity after all,

https://www.boards.ie/discussion/comment/121618197#Comment_121618197

Building regs would suggest that a fireman switch is also required. It doesn't matter if the power entering the building is Ac or Dc. I have microinverters which convert the Dc from the panels to Ac pretty much at source, so I have Ac entering the building and by right it seems I should have a fireman switch.

graememk

https://www.boards.ie/discussion/comment/121615966#Comment_121615966

I don't have IS10101.

Is that quote from the seai (because it mentions "under this scheme" or is it from IS10101 /part B directly?

There was a change in policy around the fireman switch/battery backups in the seai in 2022 ish

I have no issues with seai requiring what they want. Their grant their rules.

https://www.boards.ie/discussion/comment/121618417#Comment_121618417

I don't have access to my copy at the moment but I think I remember reading about it being a requirement, not 100% on that.

"Through these requirements of Part B of the building regulations and I.S. 10101" My reading of that is that they're the requirements of IS10101 and Part B and as such need to be adhered to "under this scheme".

I think it benefit the forum to get confirmation about this because I often see it repeated that the shunt can be removed after the grant is paid.

con747

https://www.boards.ie/discussion/comment/121618755#Comment_121618755

Ignorance is the best defence! I just had to 😂

https://www.boards.ie/discussion/comment/121619426#Comment_121619426

😁 I'm lead to believe it's also bliss.

con747

https://www.boards.ie/discussion/comment/121619473#Comment_121619473

In fairness you are right though, we need some clarification on the rule with the fireman switches because I was under the impression it was just a requirement for the grant like most SEAI red tape box ticking requirements. I had a quick look but couldn't find anything 100% on it.

Buffman

https://www.boards.ie/discussion/comment/121613314#Comment_121613314

Basically it's a safety issue and done to prevent 'Islanding', which is where if your solar power was still on it could be sent back down the power line and become a safety risk for the ESBN staff working to fix the problem on a line they believe is off.

on_the_roots

There must be another reason for Islanding prevention other than "protect ESB staff". How come a professional electrician will touch a public electric grid in a power cut assuming 100% sure there will be nothing on the line in the first place?

You only assume that when working in an installation you can physically see and verify there is nothing feeding the wires.

Even if you enforce PV systems to automatically disconnect from the grid there is nothing preventing someone connecting a generator to their mains...

graememk

https://www.boards.ie/discussion/comment/121630082#Comment_121630082

Its just good practice, Yes they will ground lines if they are working on them (see bobsdecline on youtube) And othertimes they do work "hot" as the canadian puts it.

Yes nothing stopping people from doing dangerous stuff like that ( and it will often overload whatever generator you connect, A 3kw jenny wont power a street of houses!) but in the interest of everyone its important that every precaution is taken.

Besides a grid tied inverter needs the [a] grid to work, and cant work without it. [ as a grid tied inverter, a battery one can work as a off grid inverter on its own, and even create a micro grid)

on_the_roots

https://www.boards.ie/discussion/comment/121630318#Comment_121630318

In my case I have a Projoy Safety switch wired in such a way that without grid power it automatically disconnects the panels from the hybrid inverter. So I would have an off-grid inverter but powered by the battery alone, no panels.

https://www.boards.ie/discussion/comment/121619558#Comment_121619558

https://www.boards.ie/discussion/comment/121618417#Comment_121618417

See below.

graememk

https://www.boards.ie/discussion/comment/121630767#Comment_121630767

That's as clear as it can be.

What I do take from it is.

It's just for PV (although micro wind and micro hydro is tiny)

If a house is totally off grid, I suppose it doesn't fall under is10101?. Or that it's main ac supply is the inverter. By turning that off it will isolate the AC supply.

It doesn't specifically say like the seai, that it can't be powered in off grid mode, and running through a changeover sorta makes it off grid.. kinda? 😂

(Measured the power of my fireman switch today, 3w!)

_ptashek_

https://www.boards.ie/discussion/comment/121615966#Comment_121615966

I'm looking to install PV next year, and looking at this... this is just daft! There is gear which can do anti-islanding safely, and fully automatically, so why force the PVs to disconnect on loss of mains? I get the idea of DC disconnect, but that could be just an externally accessible manual breaker. If emergency services need it, it's marked, it's accessible, they just flip it.

It's as paranoid as not allowing standard sockets in bathrooms "because it's a health and safety risk". Most of the world should be dead by now, if all that nonsense were true.

So, there goes my idea of powering the entire house from solar, with the grid taking more of a backup supply / side income role.

https://www.boards.ie/discussion/comment/121631003#Comment_121631003

Yes, specifically for Pv.

Agreed about off grid but building regs need to checked as it may be in that too.

Might be a bit of stretch with the changeover🤣

https://www.boards.ie/discussion/comment/121631270#Comment_121631270

I suppose the intention is that the isolation is automatic. A manual switch might not always be accessible depending on the fire/emergency.

tandcapply

I think that this is somewhat related to rhe original question.

Is there a way of having societs that will work in the event of a power cut?

Hybrid inverter but no battery.

Jonathan

https://www.boards.ie/discussion/comment/122050676#Comment_122050676

A hybrid inverter can do this, but you need a battery.

tandcapply

https://www.boards.ie/discussion/comment/122050704#Comment_122050704

Is installing a battery the only way of getting any solar power in the event of a power cut?

slave1

You won't have solar power, you'll have whatever power is in the battery (assuming fireman in operation)

Grumpypants

@con747 Was there a specific name for the switch that lets you charge the battery from panels? I have the change-over switch so can run the house from the battery and it's killing me to be without grid power now until Feb 5th and have panels sitting there doing nothing. Even 2kw would let me flush the toilet and turn on the heating.

I want to call the guys but don't want to sound like a dope asking for the wrong thing :)

con747

https://www.boards.ie/discussion/comment/123105338#Comment_123105338

No specific name, I just asked for a change over switch to be fitted and it has paid for itself over the weekend with no power the whole house was running off batteries and solar. Picture of the switches below, I just flick the AC switch and the brown change over switch down in power cuts. My fireman switches are bypassed during power cuts to allow the panels to charge the batteries.

graememk

https://www.boards.ie/discussion/comment/123105338#Comment_123105338

You need to power the fireman switch someway. It's usually tapped off the supply to the inverter so when you cut the power to the inverter, during the changeover process, so not too feed its own power to itself you also cut the power to the fireman switch.

con747

https://www.boards.ie/discussion/comment/123105338#Comment_123105338

Have a look at post #100 in the below thread.

https://www.boards.ie/discussion/2058333720/change-over-switch-grid-pv/p2

Grumpypants

Thanks, I have the changeover next to the consumer unit so sit ounds like it's just another changeover near the invertor to bypass that fireman switch.

He said he does them all the time once the grant is paid so I'm sure it's not a huge job.

ajarsm86

Sorry to be digging up a thread but with the extensive blackouts after Storm Eowyn this topic has raised it head for a number of my neighbor's.

My next door neighbor has a pretty sizable solar array and battery set up (they say large enough to run the house) just as mentioned before the shunt/inverter has shut off since we all lost power last Friday and they cant use the masses of energy stored in their batteries.

So if a Solar PV system is stalled as per the regs mentioned above how does one use the power from their batteries during a black out? (surely this is one of the main reasons for getting Solar PV with battery back up)? seems crazy the regs prevent you from using that power?

10000maniacs

A bit silly cutting out when you need them most. Like in a bloody power cut.

If they powered a little LCD television and one bar of an electric heater during a power cut in daylight, it would be the least to expect from solar panels. Or a ring of the cooker to boil a few eggs.

Back to the drawing board guys with your solar panels.

slave1

The answer is already here in multi threads. In Ireland all inverters are by law grid tied (unless the install is out in the woods off grid) so than when power is cut there is no PV/Battery power feeding back into the lines to protect people working on those lines.

Most inverters have an EPS function where you can wire in a 3pin socket and run essentials off that once within the power capabilities of your battery/inverter.

Alternatively at greater expense a changeover switch can be installed to take you "off grid" temporarily to utilise both your panels as well as battery storage.

The choice is there and no doubt will now be an option for new installs going forward but options is/was always there