A word of warning before installing solar in older house

Wyldwood · 22-03-2026 08:27PM #1

We recently had a 12 panel 5.7kWh solar system installed and the day the electricians finished they informed us we needed to upgrade the tails from meter box to fuseboard as they were only 10mm² and we now apparently need 16. This is going to cost a significant amount extra that we hadn't factored into the initial costings. I'm very upset that this wasn't flagged before work started, as we probably wouldn't have gone ahead. What's more annoying is that the company sales rep (with several renewable energy qualifications) looked into the meter box but didn't mention anything about the tails.

The electrician switched the system on and it is working well and the install is very neatly done but he said he could only do this as a temporary measure as we don't have an electric shower, heat pump or EV charger, and with no intention of getting them at this stage in our lives, but the upgrade will need to be done asap.

So, if you live in an older house make sure to ask if the tails to your fusebox are big enough to take the extra load and don't get caught for this extra expense afterwards.

17larsson · 22-03-2026 09:48PM

If you don't have an EV charger, heat pump, or electric shower then 10sq is fine

10-10-20 · 22-03-2026 09:51PM

Highly unprofessional of them. It should be a key part of their initial evaluation or site survey.

I'd be putting significant pressure on them to admit their mistake and looking for some financial support to have the tails upgraded. I'd be seeing a solicitor if the noises in return were not favourable.

Do you mind me asking how much the tails upgrade was estimated or quoted to be? I'm thinking it's north of 4k?

paulpd · 22-03-2026 09:56PM

We got upgraded from 10sq to 20sq recently. New earth rod chamber, earth bonding and inspection and RCCI cert totalled additional 7k on the renovation.

Fann Linn · 22-03-2026 10:00PM

https://www.boards.ie/discussion/2058436196/a-word-of-warning-before-installing-solar-in-older-house

What do you mean by older house? 10/15/20/50 years old?

graememk · 22-03-2026 10:10PM

Mine had 10mm2 built 1980.

Parents house, when they moved the ESB meter in the early 80's is 16mm2.

Likely 45+ years old.

Would say to op about the fusebox, how recent is it? Mine was still screw in fuses without RCD protection before I upgraded it.

Wyldwood · 22-03-2026 10:13PM

10-10-20, we have no definite price yet as the whole house will have to be checked out before final cert is issued and don't know what that will throw up but a figure of €2k was mentioned.

Fann linn, house is 40 years old.

Wyldwood · 22-03-2026 10:19PM

https://www.boards.ie/discussion/comment/124333416#Comment_124333416

Our fusebox is original to house, 1985 but has RCDs. There was talk of having to get new fusebox too, the whole thing has turned into a can of worms.

17larsson · 22-03-2026 10:19PM

You said you have no heavy loads currently so 10sq is fine for a solar install.

https://safeelectric.ie/contractors/tech-information/a-focus-on-relevant-clauses-for-solar-photovoltaic-pv-systems-and-the-use-of-automatic-changeover-switches/

Sleamhain · 22-03-2026 10:47PM

You don't need your tails upgraded for Solar PV. There is no harm in doing it, but not necessary.

The electrician is talking waffle

If they have turned it in as a temporary measure....what does that even mean? If it's on, its on. If it couldn't be switched on for safety.....then you wouldn't just say, ah we will turn it on for a little bit.

Pay them for what they have done, and don't bother with the rest of you don't want it.

Unless they have found something warranting a safety issue, but they haven't issued any notice of potential hazard?

Wyldwood · 22-03-2026 11:24PM

Thank you all for the helpful comments. We haven't been issued with a notice of potential hazard. We will go back and ask for more information from the installer about why they told us to get the tails upgraded before we go any further.

ted1 · 22-03-2026 11:35PM

https://www.boards.ie/discussion/comment/124333372#Comment_124333372

we got a while house rewired 167sq m. 4 bedroom, out house , car charger , outdoor lights etc. for 17k including tails upgrade from 6mm to 16mm

7k sounds mental .

geographica · 22-03-2026 11:52PM

tails? Help those that don’t know

graememk · 23-03-2026 12:11AM

The wires from the ESB meter to the fusebox (also the wires from the ESB fuse to the meter too)

geographica · 23-03-2026 12:14AM

cheers

10-10-20 · 23-03-2026 09:57AM

Just as a follow-up, the question which should be asked here is: What were the qualifications of the individual who made the determination that the tails needed to be upgraded. Because that's what matters here. In my response I was taking it at face-value that the person who said it was suitably qualified to do so, but that's not always the way with some of these one-stop shops.

graememk · 23-03-2026 12:16PM

And the house is 40 years old, original fuse board, etc is not inherently unsafe but would be at end of it's life. Possibly something to keep in mind.

magicbastarder · 27-03-2026 10:17AM

would the SEAI be interested to know that a (presumably) SEAI approved installer made a basic error like this?

daheff · 27-03-2026 10:26AM

have you gotten independent advice from another electrician yet? I suggest you do that before you commit to any costly works.

Solar electrician could just be erring on the side of caution and suggesting an upgrade is needed rather that required. Covering his arse in case something goes wrong

TheWonderLlama · 27-03-2026 10:35AM

we don't have an electric shower, heat pump or EV charger,

Most people, after getting solar, install one or more of these , so it may be that the electrician assumed this and would then be correct in saying the tails need to be upgraded. If you are not intending to get any of them installed and the system is up and running, then leave well enough alone.

micks_address · 31-03-2026 04:24PM

i would say if anyone is upgrading tails - make sure they put in 25mm2 tails… i had mine upgraded for the ev charger only couple of years ago to 16mm2 - but now im interested in upgrading the house supply from standard 12kva to 20kva tails need to be changed again… better be done with it once!

A word of warning before installing solar in older house

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