Earthing a 12 V inverter

Calahonda52 · 27-03-2026 09:03AM #1

ESB power to the house I am refurbishing may need to be cut due to a 6 week wait of ESB to drop the cable.

Builder is staring next week but he has lots of work to do before here is anywhere near the

The problem that poses is that I have an electric gate.

I have a 2.1 kWh battery and a 12v inverter with an earth terminal on the front.

Recharging the battery will not be am issue

Just wonder is there safe way to earth the inverter.

Thanks as always

10-10-20 · 27-03-2026 10:23AM

https://www.boards.ie/discussion/2058436381/earthing-a-12-v-inverter

Hi Calahonda,

Clarifying question, or five: It's a 2.1kWh, 12v battery onto an inverter which converts to AC at 230v? Is the that right interpretation?

It's also a portable inverter, and not intended as a wall-mount inverter, right? What does the sticker say on the inverter say in terms of output voltage as I'm going to guess that it could be a simple type outputting 110v on both N and L.

Calahonda52 · 27-03-2026 05:03PM

https://www.boards.ie/discussion/comment/124344798#Comment_124344798

Thanks.

https://www.amazon.de/dp/B0BFB1JZJQ?ref=ppx_yo2ov_dt_b_fed_asin_title

This is one of them 1.5 kW so I think its a proper inverter

2nd one 2.5kW

https://eur.vevor.com/pure-sine-wave-inverter-c_10760/pure-sine-wave-inverterpower-inverter2500w-dc-12v-ac-230v-lcd-car-inverter-p_010436348686

10-10-20 · 27-03-2026 05:54PM

https://www.boards.ie/discussion/comment/124345693#Comment_124345693

I could be wrong here, but it's probably still a split-phase inverter, meaning that both "L" and "N" output terminals are 'live', but the voltage output from L is 120v AC and its phase is 180 degrees out from the AC voltage on N, meaning that the voltage read between L and N will be 240v AC, but will only be 120v from either phase to earth.

In that case it's like one of those 110v AC site transformers where there isn't an earth as it's fully decoupled from the mans 240v, but there is no path to earth for the 110v so the risk of electrocution is far lower. Normally those systems do not get grounded for that reason. And you also don't fit an RCD/RCBO (but an MCB may be advised) as there is no fault path to earth, so the RCD can't detect any leakage.

But I'm just some randomer off the internet, so take advice off a trusted sparks. 😁

https://powmr.com/blogs/news/what-is-split-phase-inverter?srsltid=AfmBOoquv2Z_rpMgLh23Tl_HQv8IZkh4R93BOmtAeAhKmZiBPsso5Eq0

Calahonda52 · 27-03-2026 06:46PM

Thanks for your help.

So from one randomer to another, if I put one prong of the voltmeter in one of the output terminals and the other to the house earth, then it will read either c 110 or 240 or so?

Having said that both have earth terminals at the back

10-10-20 · 27-03-2026 08:17PM

https://www.boards.ie/discussion/comment/124345911#Comment_124345911

No, try between E an L, then E and N on the output of the device. That's my understanding of the theory anyway.

29-03-2026 02:58PM

https://www.boards.ie/discussion/comment/124346089#Comment_124346089

Agreed as it will have no reference to earth.

whizbang · 30-03-2026 12:59AM

Most of these inverters are 'transformerless' i.e. theres no output transformer, and absolutely no thought whatsoever of earthing..

But if there's an earth terminal, I would be concerned that it may have issues if the battery has an earth reference somewhere..

10-10-20 · 30-03-2026 09:49AM

https://www.boards.ie/discussion/comment/124350104#Comment_124350104

Are they still double phase like i suggested?

The Continental Op · 30-03-2026 11:41AM

My first thought on reading the thread was has anyone looked at the gate motor to see what voltage it is?

Would be a bit daft using an inverter if the motor turned out to be 12V DC? Well 12V DC might be wishful thinking but I know some gate motors are 24V DC. It would take a bit of jury rigging but if you can cut out the inverter and the 220V AC it might be safer and no worries about earthing?

10-10-20 · 30-03-2026 11:44AM

https://www.boards.ie/discussion/comment/124350568#Comment_124350568

Applying logic eh?

Calahonda52 · 30-03-2026 01:05PM

It's mains, as I had to lay the 2.5 sq for it and its plugged into a socket.

Looking at it another way, what if I connect the earth from the gate to an earth rod and ignore earthing the inverter

10-10-20 · 30-03-2026 01:24PM

https://www.boards.ie/discussion/comment/124350729#Comment_124350729

But that's not creating a circuit, it's creating a gate which is bonded to earth, but the inverter has no path to earth, so it's an open circuit and provides no protection against earth leakage.

Did you happen to measure the voltages on the output of the inverter?

I think that the answer to your question is to look for similar examples in the off-grid mobile-home groups, but you have to know whether your inverter has an internal N-E bond first (which I think it will not have).

zg3409 · 30-03-2026 01:26PM

I would recommend leaving live things to an electrician, like if you have to ask ..

Make sure whatever you do is waterproof especially with sideways and upward rain.

The Continental Op · 30-03-2026 01:32PM

https://www.boards.ie/discussion/comment/124350729#Comment_124350729

They all have a mains controller box but that often puts out 24V to the gate.

Calahonda52 · 30-03-2026 06:13PM

https://www.boards.ie/discussion/comment/124350788#Comment_124350788

OK, missed that subtlety in your first post, of course what's new😀

Keep well and enjoy that view

Calahonda52 · 30-03-2026 06:17PM

https://www.boards.ie/discussion/comment/124350777#Comment_124350777

In cased you missed it: this is what I asked:

Just wonder is there a safe way to earth the inverter.

Calahonda52 · 30-03-2026 06:22PM

https://www.boards.ie/discussion/comment/124350771#Comment_124350771

Not yet as am snowed with the day job.

I have two so I will try both when I get a chance.

Thank you very much for your inputs, I appreciate them even if I don't fully understand them

Lenar3556 · 06-04-2026 08:13PM

https://www.boards.ie/discussion/comment/124351553#Comment_124351553

The inverter is a very different affair to the 230v entering you house and the principles of earthing that apply in a house don’t apply to the inverter - because it’s isolated from earth in the first instance.

For the application you describe, whereby the inverter is providing a connection to a single appliance (the gate controller), you can usually just plug it in to the 13A socket without any additional earthing consideration.

If you were using the inverter to power a fixed installation, there may be additional considerations.

Earthing a 12 V inverter

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