Plug in solar

It's magic! lol

The answer is actually straightforward. If you grid is coming into your house (and to the microinverter) at say 230v, the micro-inverter will produce a voltage of a little bit higher….say 235v. This power goes back to your consumer board (fusebox) and devices hanging off that will take the electricity from the highest voltage first. Since in this case your Micro-inverters are giving out 235v, your fridge/TV/xbox/etc will take and use that first before the grid power. That's a little simplistic, but it's essentially what happens

Interesting… though I have Powerline Adapters for my network (i.e. using the internal electricity cables to act as ethernet), does the incoming power do anything funky to those?

It's not currently approved by who?

What specifically are ESB blocking or not approving?

I think the issue isnt that 1 of those 400w or 800w microinverters are the problem, but no way to control now many could be used and not just in the same property, but also possibly on the say circuit inside that property.

I asked our digital friend for a breakout of that thought:

Example 1: 20 A radial in 2.5 mm² twin-and-earth

Assume:

• a 20 A MCB protects a socket radial
• sockets are laid out CU → A → B → C
• someone plugs:
  • plug-in solar 1 into A = about 3.5 A
  • plug-in solar 2 into B = about 3.5 A
  • kettle into C = about 13 A

An 800 W microinverter at 230 V is about 3.48 A.

In that exact moment, the current in each section is roughly:

• B → C: kettle current minus Solar 2
  about 13 - 3.5 = 9.5 A
• A → B: kettle current minus both solar units
  about 13 - 7 = 6 A
• CU → A: again about 6 A

So in that one arrangement, nothing looks terrible.

But now change only one thing.

Same radial, but kettle at A and both solar units farther away

Now imagine:

• kettle at A = 13 A
• Solar 1 at B = 3.5 A
• Solar 2 at C = 3.5 A

Then:

• CU → A may only see the net import, around 6 A
• but the section A → B can have solar current flowing back toward A
• and B → C can have solar current flowing back toward B

That is where the IET concern comes in: the protective device at the consumer unit only sees the net current at the origin, not the current in every bit of the final circuit. Their March 2026 warning specifically highlighted risks of overload or backfeed on final circuits with plug-in solar.

Where Ireland gets uncomfortable

For ESB Networks, the issue is not just “can one kettle be partly fed by nearby solar.” Their microgeneration policy is built around a known generating installation with a declared total capacity. They explicitly assess aggregate generating capacity and, where multiple inverters exist on one site, the combined inverter rating matters.

So from an Irish network / compliance point of view, the red flags are:

• uncontrolled aggregation
  one 800 W unit becomes two, then three, without the site’s declared inverter total being clearly managed.
• final-circuit uncertainty
  nobody can trust that end users will keep the “good” arrangement you described instead of moving plugs around.
• non-designed connection method
  Irish electrical compliance is based around regulated electrical works and certification by a Registered Electrical Contractor for applicable works, not ad hoc generation plugged into random sockets.
• standards / anti-islanding / interface compliance
  ESB’s microgeneration rules also require compliant generating equipment operating in parallel with the public network.

Very practical Irish “bad day” example

Say a person has a normal socket circuit and thinks:

• “I’ll put one 800 W balcony solar in the kitchen”
• “another in the utility”
• “another in the box room”

Now somebody else in the house later plugs in:

• kettle
• toaster
• portable heater
• extension lead

Even if each plug-in solar unit is “small,” the house wiring is no longer being used the way it was designed or verified. The breaker may not necessarily trip in the way a layperson expects, because it is only seeing the net current at the board, while some local sections of circuit and some accessories can still be stressed. That is exactly the sort of uncontrolled scenario the IET is warning about, and it fits very neatly with why ESB Networks would prefer declared, fixed, assessed generation rather than casual plug-and-play additions.

So in plain English

What would ESB Networks likely dislike most?

Not being able to trust that:

• the total inverter capacity on the premises is known,
• the wiring arrangement is sensible,
• the generation is connected in a controlled way,
• and the user will not keep adding more units or moving them around.

That is why your instinct is good:
“What stops people going mad and plugging multiples into one radial?” is not the whole Irish objection, but it is absolutely in the middle of the practical problem.

Yes I watched him last week and now an ecoflow stream micro inverter is on it's way. A couple of panels from done deal and the whole setup could cost as little as €220. I'm going to get bifacial panels so I can do a bit of experimenting on placement but even at that the total cost should be circa €283.

Yep.

Including VAT

Just to go back to the question "Why would ESB networks be against it?" - well I think there's actually a number of reasons.

I'm of the personal opinion myself that 1x microinverter with 800w of panels (should) be a relatively safe operation. The issue that I would have with plug in solar ….is that "people being people" will do things which will make their installation unsafe, not to give the finger to the utilities, but because they don't know any better. Sometimes you need to save people from themselves. LOL

For example, the temptation is there that since they are good for reducing utility bills, that someone will plug 2 or 3 or more of these things into an extension cable down at the bottom of the garden and basically place loadings on cables which were never designed for it, with shoddy cabling etc insufficient breakers/fuses/etc

Currently a solar install in Ireland is completed by a spark, usually isolating the solar installation onto it's own (bi-directional) RCBO circuit breaker. Older houses in Ireland don't have these bi-directional devices as they were never a requirement originally.

I guess currently, we hope, there is some competence over-seeing the installations as opposed to random lunatics setting up adhoc installs thinking "it'll be grand" :-)

Again, I'd be a fan in general of plugin solar….

While what your saying is right, that being that ESB networks own the network and not the wiring…..unfortunately it's a little more complicated than that. One of the problems with solar on grids is the "balancing of phases" back at the substations. Your typical estate will have every third house on a separate phase. With NC6 connections, ESB networks gain an understanding of what's going on in an area. Opening that up to people doing as they will, you lose that insight and you could potentially create issues.

Now with the relatively modest generation capacity of say 800w on a plugin solar installation, that will basically be absorbed (mostly) by base load of the house in question or the next doors at most - but if a few people go "a bit nuts" and the phases get out of sync…..you could have some issues.

Again, I'm hoping that there's a good way forward here. I'd be a fan of getting as many people on a green path as we can. We need that. Maybe there could still be a way to do an "fit and inform" (similar to an NC6) so that a householder can install it, and voluntarily fill out the details on a website. Least there'd be some insight of what's happening, even if compliancy wasn't 100%

Ecoflow stream arrived. Bought 2 x 530W damaged panels for €20. Total cost €138.40.

Ecoflow is outputting 600W max. (capped for some reason - plenty of posts online).