Problem diagnosis · Sofar Solar

Sofar ME3000SP EPS Mode Fault — Neutral-Earth Bond & Backup Power Fix

Your ME3000SP has battery storage but doesn't provide backup power when the grid goes down. The most common cause on UK installations is a missing neutral-earth bond on the EPS circuit — the unit detects an earth fault and refuses to energise. This guide walks through the full diagnostic path.

Free remote diagnostic · pay only if we fix it — from £75 if remediable remotely

Start diagnosis

AC-coupled BESS (2016–2021 installs)
Neutral-earth bond specialist
Uses SolarMan monitoring

ME3000SP not backing up?

We diagnose whether the issue is configuration, neutral-earth bond, changeover relay, or battery SoC — then tell you exactly what needs fixing.

Book your free remote diagnostic Back to Sofar hub

Independent — not affiliated with Sofar Solar.

5.0

Rated 5.0 on Google Read all 48 reviews

Massively massively recommended. We had a big battery array (49kW across three phases) put in four years ago. c £35k cost. It’s been a total nightmare for many reasons, not least 1. our installer being totally useless and unresponsive and 2. Givenergy, our battery supplier, going bust. Long story short it had never worked anywhere near properly despite countless hours on phones and emails; the best we’d achieved was one third of the batteries working. Rather than write it off, I asked a PM friend to try to source someone who could come on site and review and revive the system. He found Solar Tech Support and Ron. Ron assured us he was the man to get it going again. After so many years of pain, I was not convinced but, true to his word, five hours later it was up and running. Lovely chap, super knowledgeable with a support team to lean on who are also clearly super technical. I honestly didn’t think there was much chance of getting this array going ever again so was absolutely delighted when Ron and team pulled it off. Bravo!

Will Wynne · Jun 2026 Google

Our 3 year old GivEnergy batteries froze. They were showing 0% on the app, but they were fully charged. Some how Ron took over our inverter and remotely cured the problem. We live in King’s Lynn, he is in Leeds I believe. Very grateful.

David Lewin · Jul 2026 Google

Amazing support, went out of his way to help try and get us back up and running

Paul Smith · May 2026

A really big thank you to Ron and his team, he has vast amounts of knowledge and got my system back up and running, also good to get on with. I was absolutely lost as to know what to do, no help from installer and somehow came across Ron and am I glad I did. I would definitely definitely recommend him to anyone who has faults with there solar system, any make I would say. Thanks again Ron a pleasure meeting you.

D R · Jun 2026 Google

I can’t praise this firm enough. After hearing my solar panels rattling in very windy conditions, I contacted Solar Tech (as my installers no longer trade). Ronald was fantastic at explaining what he thought the issue was likely to be. Communication was great throughout keeping me fully updated. The team worked really hard on the day to carry out the necessary work. I can now sleep soundly at night without worrying about the solar panels on my roof. I would thoroughly recommend this firm. Thank you for sorting the problem out.

Carolyn Addison · Jun 2026 Google

Contacted Solar Tech Support when trying to understand what my Givenergy inverter problem might be and what might be my options. Received good/honest advise which backed up my thoughts.

Hugh Speirs · Apr 2026

Will Wynne · Jun 2026 Google

D R · Jun 2026 Google

Carolyn Addison · Jun 2026 Google

ME3000SP EPS fault Grid disconnection Sofar hub →

Safety: The ME3000SP EPS circuit involves mains-voltage wiring and earthing. Neutral-earth bond installation and changeover relay work must be carried out by a qualified electrician. Do not modify consumer unit wiring yourself.

Diagnostics

5-step ME3000SP EPS mode diagnosis

The ME3000SP can provide backup power during grid outages, but only if three conditions are met: EPS mode is enabled, a changeover relay is installed, and the neutral-earth bond is present. Most failures trace back to one of these three.

Check EPS mode is enabled in the ME3000SP settings

EPS mode is a configurable option — it is not active by default. Navigate the ME3000SP LCD menu to the EPS settings screen, or check in SolarMan under device configuration.

• EPS enabled = On: The unit will attempt backup power when the grid drops

• EPS enabled = Off: The unit ignores grid outages entirely — no backup attempt

Many ME3000SP installations were commissioned without EPS enabled because the changeover relay wiring was never completed. If your installer went bust before finishing the EPS circuit, this is the most likely state.

Verify the changeover relay or transfer switch is installed

The ME3000SP requires an external changeover device to isolate backed-up circuits from the grid during an outage. Without it, EPS mode cannot function safely.

• Check the consumer unit for a changeover relay between the grid supply and the backed-up circuits

• Some installations use a manual transfer switch instead of an automatic relay

• If no changeover device is present, EPS cannot work — regardless of the ME3000SP settings

The changeover relay ensures the ME3000SP never back-feeds the grid during an outage — this is a G98/G99 safety requirement.

Check the neutral-earth bond on the EPS circuit

This is the single most common cause of ME3000SP EPS failure on UK installations. The mechanism is straightforward:

Why the neutral-earth bond matters

Normal operation: The neutral-earth reference comes from the electricity supply point (DNO transformer or your incoming supply)

During power cut: The grid disconnects — the neutral-earth reference is lost

Without local bond: The ME3000SP detects an earth fault condition and shuts down for safety

With local bond: A neutral-earth link on the EPS side of the changeover relay restores the reference — EPS works

This is particularly common on TT earthing systems (common in rural UK areas). A qualified electrician must install the neutral-earth bond link so that it is only active when the changeover relay has switched to EPS mode.

Confirm the battery has sufficient charge for EPS

The ME3000SP will not enter EPS mode if the battery State of Charge is below the configured EPS minimum threshold:

• Check current battery SoC on the unit display or in SolarMan

• Check the EPS minimum SoC setting — this should be higher than the normal discharge minimum

• If the discharge schedule drained the battery before the power cut, EPS will not activate

Set the EPS reserve SoC to at least 20% to ensure some backup capacity is always available. This means the normal discharge schedule should stop at 20% rather than draining the battery to the minimum.

Test EPS mode with a simulated grid outage

Once the above checks are complete, simulate a power cut to confirm EPS works end-to-end:

1. Ensure battery has charge — at least 30% SoC

2. Turn off main grid supply at the consumer unit

3. Wait 5–10 seconds — the changeover relay should switch

4. Check backed-up circuits — lights and sockets on the EPS circuit should have power

If the relay switches but the ME3000SP doesn't energise: The neutral-earth bond is the most likely cause. If the relay doesn't switch at all: The relay wiring or the relay itself needs checking.

The ME3000SP EPS problem — why it's so common

The Sofar ME3000SP was one of the most widely installed AC-coupled battery systems in the UK between 2016 and 2021. It was popular because it retro-fitted to existing solar installations without replacing the solar inverter. Many were installed under government incentive schemes by companies that have since closed.

The EPS (Emergency Power Supply) feature was a selling point, but in practice many installations were never fully commissioned for backup power. The changeover relay was not always installed, the neutral-earth bond was frequently omitted, and EPS mode was left disabled in the settings. Owners only discovered the problem during their first real power cut — sometimes years after installation.

The neutral-earth bond issue is specific to the UK because of the prevalence of TT earthing systems, particularly in rural areas. In countries with TN-C-S earthing, the neutral-earth reference is maintained differently and the problem doesn't arise in the same way. This means manufacturer documentation from China doesn't always cover the UK-specific earthing requirement, and installers unfamiliar with EPS wiring on TT systems missed the step.

ME3000SP EPS mode — common questions

Why does my Sofar ME3000SP not provide backup power during a power cut?

The three most common causes are: EPS mode was never enabled, the changeover relay was not installed, or the neutral-earth bond is missing on the EPS circuit. On UK TT earthing systems, the loss of neutral-earth reference when the grid disconnects causes the ME3000SP to detect an earth fault and refuse to energise. A local neutral-earth bond on the EPS side of the changeover relay resolves this.

What is a neutral-earth bond and why does the ME3000SP need one?

A neutral-earth bond connects neutral to earth at a defined point. Normally this exists at the supply point. During a power cut, the grid disconnects and the reference is lost. The ME3000SP detects this as an earth fault and shuts down. Installing a local bond on the EPS side of the changeover relay restores the reference and allows backup power to work.

How do I check if EPS mode is enabled on my ME3000SP?

Navigate the ME3000SP LCD menu to EPS settings, or check in SolarMan under device configuration. EPS mode shows as enabled or disabled. If it was never turned on during installation, the unit will not attempt backup power. Enabling it also requires the changeover relay to be installed and wired.

Can STS fix my ME3000SP EPS problem remotely?

We can remotely diagnose whether the issue is configuration, SoC thresholds, or hardware. If the fault is a missing neutral-earth bond or changeover relay, on-site work by a qualified electrician is needed. We provide a clear diagnosis and specification so you or your electrician know exactly what to do. Many EPS issues turn out to be configuration rather than hardware.

What is the difference between EPS mode and normal operation on the ME3000SP?

In normal operation, the ME3000SP charges and discharges alongside the grid — importing cheap rate energy and supplementing solar self-consumption. In EPS mode, it operates as an island — the changeover relay disconnects from the grid and the ME3000SP powers the backed-up circuits directly from the battery. EPS only activates when the grid fails and the battery has sufficient charge above the EPS reserve threshold.

Book

ME3000SP not backing up during power cuts?

We diagnose EPS configuration, neutral-earth bond, changeover relay, and battery SoC remotely. Clear diagnosis, clear specification for any on-site work needed.

No fix, no fee
ME3000SP EPS specialist
Clear spec for your electrician if on-site work needed

Call 07944 877 329 Book free diagnostic