MCS is the UK quality mark for small scale renewable energy. It sets the standards that solar and battery installations are built to, and it certifies the businesses that build them.
When your system is finished, your installer raises one certificate for your installation and gives it to you. That document is what an energy supplier asks for when you apply to be paid for the power you export.
MCS is clear that it is not the law. Its own words are that an MCS certificate is not a mandatory or legal requirement for system installation. It is the evidence other people ask for. This guide covers what it contains, when you get it, why export tariffs want it, and what to do if you cannot find yours.
Key Points
- Three separate things are certified: the installer business, the products used (on a solar job that means the panels and the mounting kit), and your individual installation.
- Solar PV work is covered by MIS 3002:2025. Battery storage is a separate technology with its own standard, MIS 3012:2025, read alongside the IET Code of Practice for Electrical Energy Storage Systems.
- Installer certification is granted by an independent certification body, not by MCS itself. MCS publishes the list of bodies and the technologies each covers.
- Every MCS installation must be registered on the MCS Installations Database, the MID, and the certificate is generated from it.
- MCS requires the certificate to reach the customer within 10 working days of the commissioning date. Under the redeveloped installer scheme the window is 30 days.
- A certificate can only exist where the work was commissioned by an MCS certified installer, used an MCS certified product, and has a commissioning date after 15 July 2009.
- Ofgem's Smart Export Guarantee guidance says an eligible installation must show that the installation and installer are suitably certified, must have an export meter, and must have an export MPAN.
Common Misconceptions
"MCS certification is the law." It is not. MCS says an MCS certificate is not a mandatory or legal requirement for system installation.
"Without MCS you can never be paid for export." Not quite. Ofgem recognises equivalent schemes, and says a supplier that cannot see certification is not obliged to pay but may choose to.
"MCS only certifies the panels." It covers the installer business, the products and the individual installation.
"The installer can add MCS afterwards." No. MCS says an installation cannot be certified retrospectively, and that where a certificate was never issued it cannot raise a new one.
"The certificate is a guarantee of the system." It is not. MCS states it will not be held liable for issues with your system, and that a certificate is no guarantee of access to any government incentive scheme.
Real-World Advice
Our published 17 panel installation in Hailsham is a 7.99 kWp array with a 10 kWh battery. See the Hailsham case study. The customer wrote that the job took six weeks from first contact to finish, and that Lee came back the day after the install to check everything was as they wished.
The certificate belongs at the end of those six weeks, not the middle. It is raised once the system is commissioned, because the commissioning date is a field on it.
Eastbourne Energy is MCS certified. Our installer certificate number is NAP67611, held with NAPIT.
What the certificate says
| On the certificate | What it tells a supplier |
|---|---|
| The type and model of the installed technology | The equipment is a certified product |
| The installation company and its certification details | A certified business did the work |
| Confirmation that the system complies with MCS standards | The work was checked against a published standard |
UK-Specific Considerations
Why an export tariff asks for it
Ofgem's guidance for Smart Export Guarantee generators says that for solar PV up to 50 kW, both installation certification and installer certification are required. It says the certificate may be a Microgeneration Certification Scheme certificate, but that the SEG also recognises that other schemes may be equivalent to MCS.
That is the whole of "MCS or equivalent". Where there is no MCS certificate, Ofgem says the installation and installer should be accredited in accordance with EN 45011 or EN ISO/IEC 17065:2012, and that you should ask your chosen supplier what it needs. If you cannot show any of it, Ofgem says a supplier is not obliged to offer payments, but can pay if it wishes. So this is an eligibility condition applied by suppliers, not a ban written into law. The steps are covered in the SEG tariff application process.
Where else it gets asked for
MCS says certification is required for several government incentives, including the Boiler Upgrade Scheme, the Home Energy Scotland Grant and Loan and the Warm Homes: Local Grant. It also says many insurers require MCS for renewable technologies at a policyholder's address, that finance companies may require it for their best lending rates, and that building control and some planning authorities may ask for a certificate. One further line matters: an installation cannot be certified retrospectively.
It is separate from the grid paperwork
Telling the network operator about your system is a different job. MIS 3002 requires the MCS contractor to notify the Distribution Network Operator under EREC G98 or G99, the route described in the G98 application process. Neither document replaces the other.
When This Isn't Right For You
MCS does not cover everything. Installer certification for electrical technologies runs up to 50 kW, and MIS 3002 covers solar PV up to a maximum DC output of 50 kWp. Above that there is no MCS certificate. Ofgem's table reflects this: for solar PV above 50 kW and up to 5 MW, installation certification is required but installer certification is not, and the supplier decides how it satisfies itself.
It also does not help after the fact. If your system was installed and no certificate was ever raised, MCS says it cannot raise a new one.
Before You Spend Money
Check the installer is MCS certified for the exact technology you are buying. Solar PV and battery storage are separate certifications, so a business certified for one is not automatically certified for the other. MCS publishes a find an installer register.
Ask which certification body holds their certification, and ask when the certificate will be raised and how it will reach you. MCS allows installers to send it electronically straight from the database. Get both answers in writing.
Check the details the day it arrives. Address, postcode, MPAN, commissioning date and product details are all fields a supplier will read. Errors can be corrected, but each amendment needs evidence. Then keep it with the rest of your handover pack, because you will need it for an export tariff and possibly again for insurance or a future sale. Our own survey, install and handover process is on solar installation.
Frequently Asked Questions
Q: Is an MCS certificate a legal requirement?
A: No. MCS says an MCS certificate is not a mandatory or legal requirement for system installation. It matters because export tariff suppliers and several grant schemes ask for it.
Q: When should my certificate arrive?
A: MCS requires it to be obtained from the MCS Installations Database and provided to the customer within 10 working days of the commissioning date. Under the redeveloped installer scheme the window is 30 days.
Q: What does "MCS or equivalent" actually mean?
A: Ofgem's SEG guidance says other schemes may be equivalent to MCS, and that where there is no MCS certificate the installation and installer should be accredited in accordance with EN 45011 or EN ISO/IEC 17065:2012. Your chosen supplier decides what it will accept.
Q: I have lost my certificate. What now?
A: Contact your original installer first. MCS will only produce a copy itself if that installer is no longer MCS certified or no longer trading, and only for the current system owner or their legal representative. Proof of address and an admin fee are required.
Q: I bought a house that already has solar. Can I get the certificate?
A: The same route applies, and copies go only to the current system owner or their legal representative. You can also ring the MCS helpdesk to check whether a certificate exists at all, giving the technology type and the full address including postcode, plus proof that you live there.
Summary
MCS certifies three things: the business, the products and your particular installation. Your installer registers the job on the MCS Installations Database and hands you the certificate, within 10 working days of commissioning. It is not a legal requirement for having solar fitted, and MCS says so plainly. It matters because Ofgem's export tariff rules require an eligible installation to show that the installation and installer are suitably certified, and because insurers, lenders and some grant schemes ask for it too. If it is missing, start with your installer. MCS can only step in when that installer has stopped trading or stopped being certified, and it cannot create a certificate that was never raised.