GUIDE · FOR UK SOLAR INSTALLERS · 9 MIN READ

MCS Installations Database (MID): Registering a Job and Issuing the Certificate

The short answer

The MCS Installations Database (MID) is where an MCS certified installer registers every in-scope job and creates the customer's MCS certificate. Only the contractor that holds the customer contract can do it, once the system is fully commissioned. Under the current scheme MCS's guidance says within 10 working days of commissioning; the redeveloped scheme allows 30 days. A certificate costs £30 plus VAT. For solar PV the scheme stops at 50kWp.

Every rule, deadline and fee below comes from MCS's and Ofgem's own documents, listed at the end. Where MCS's documents disagree with each other, we say so.

What the MID is

MCS describes the MID as holding the information of every MCS certified small-scale, low-carbon installation in the UK. Its own documents give different start years, 2008 in one place and 2010 in another. It also holds the records of current and former MCS certified installers and products. MCS says DESNZ and Ofgem use the data, and the aggregate figures feed MCS's public Data Dashboard.

For you, it is the system that turns a finished installation into an MCS certificate. Individual certificates aren't publicly searchable: a system owner checks one exists by calling MCS.

Who can register, and how you get access

Your certification body grants your MID login. If you are suspended or removed from the scheme, access is revoked. Getting certified in the first place is covered in our MCS certification guide.
Only the contracting installer registers. MCS: "The registration shall only be done by the MCS certified contractor who entered into the contract with the customer." A subcontractor doesn't register a job they fitted for you.
Only after commissioning. Registration happens "when the installation is fully complete and commissioned, and not before."

The deadline

The clock starts at the commissioning date, not the end of the contract. MCS's own documents don't quite agree on the length:

Source	What it says
MCS installer MID guidance	Within 10 working days of the commissioning date. MID won't accept a commissioning date more than 10 working days back without a late reason.
MID's late-certificate prompt	Within 14 days from commissioning.
Redeveloped installer scheme	Certificate creation windows of 30 days instead of 14. The Installer Operating Requirements say 30 calendar days.

The safe habit is to treat 10 working days as the limit until you are on the redeveloped scheme. A late certificate can still be created, but you pick a reason from a list and MCS records every late submission, so it shows up when you're assessed.

What you enter for a solar PV job

From MCS's step-by-step guide for Solar PV, Wind and Micro CHP. Have these ready at commissioning and the certificate takes minutes:

Contract and cost

Domestic or commercial contract (commercial also asks for a project type), technology, any government incentive, and the overall cost including VAT. The cost has a £1,000 floor and a £150,000 cap, and you can't edit it yourself afterwards.

Customer

Customer email (optional, and it lets MID email the certificate to them) and your own project reference (optional).

Commissioning

The commissioning date, and whether the array is on a pitched roof (above roof or in roof). A pitched-roof install needs an MCS certified pitched-roof kit added as a product.

Products

Every product installed, picked from the MCS Product Directory by certificate number or model, with the quantity of each.

Site

The installation address and the 13-digit MPAN (an 11-digit MPRN in Northern Ireland).

System

Total installed capacity in kW, estimated annual generation in kWh, how planning was complied with and how Building Regulations were notified, the grid connection method, and the Declared Net Capacity (no higher than the installed capacity).

Metering

Generation meter serial number, make, model and the reading at commissioning.

Guarantee, declaration, payment

Insurance-backed guarantee provider (domestic jobs only, and mandatory there), your declaration, then the certificate fee.

The estimated annual generation should match the performance estimate you gave the customer before the sale. MIS 3002 sets how that estimate is worked out and worded.

The certificate fee

MCS's step-by-step guide says the certificate price defaults to £30 excluding VAT. You pay with MID credits or add it to a basket. Build it into your job costing alongside the rest of your scheme costs.

What the customer gets, and why it matters

MCS calls the certificate proof that an installation "has been designed, installed and commissioned to the highest standard using only MCS certified products by an MCS certified installer". It goes in the handover pack, and MID can email it to the customer if you entered their email.

The main reason customers chase it is the Smart Export Guarantee. Ofgem's guidance says that for PV up to 50kW, applicants must show that both the installation and the installer are suitably certified. That can be an MCS certificate, or an equivalent scheme. Without it, an export supplier isn't obliged to pay. A late certificate means a customer waiting on their export payments, and that call comes to you.

Batteries

Battery storage is registered on MID as well, with its own certificate creation guidance, and MIS 3012 is the battery installation standard. On a PV plus battery job, follow the battery guidance for the storage as well as the PV guide for the array. Remember the battery also counts towards the DNO limit: see G98 explained.

Commercial jobs and the 50kW limit

MIS 3002 covers solar PV on permanent buildings up to a maximum DC output of 50kWp. MID lets you mark a contract as commercial, so smaller commercial roofs are registered the same way as homes, minus the insurance-backed guarantee step.

Above 50kWp there's no MCS certificate. For the Smart Export Guarantee, Ofgem's guidance says PV over 50kW and up to 5MW needs the installation certified but not the installer, so agree with the customer early which certification their export supplier will accept. Larger roofs also mean a G99 application and, for most businesses, a conversation about capital allowances on solar panels.

Mistakes, amendments and withdrawals

Most fields: edit the certificate in MID and choose "Finish making updates". That overwrites the previous version. Give the customer the updated certificate.
Fields only the MCS Helpdesk can change: date contract signed, address, government incentive, cost, technology type, project type and Technical Supervisor.
Commissioning date: request the change through MID. Once it's approved you have 24 hours to make it.
Cancelling a certificate: the MCS Compliance team handles withdrawal requests.

When a customer loses their certificate

Customers lose certificates, usually when they sell the building or sign up for export payments. MCS tells them to contact the original installer first, so keep your records and re-send it. MCS only issues a copy itself if the installer is no longer MCS certified or no longer trading. It charges £30 plus VAT for a copy, and only the current system owner or their legal representative can ask, with proof of address.

Common mistakes

Registering before the job is finished

MCS says registration happens only when the installation is fully complete and commissioned, and not before.

Getting the cost wrong

Cost is one of the fields you can't change yourself. A wrong figure means a request to the MCS Helpdesk.

Missing the window

MID won't take a commissioning date too far in the past without a late reason, and every late submission is recorded. That record is what your certification body sees.

Forgetting the roof kit

A pitched-roof install needs the MCS certified pitched-roof kit added to the products, or the certificate is incomplete.

Letting a subcontractor register

Only the MCS certified contractor that holds the contract with the customer may register the installation.

A commissioning-day checklist for MID

Commissioning date, meter make, model, serial and reading
Product certificate numbers and quantities, roof kit included
MPAN, full address and the customer's email
Installed capacity, Declared Net Capacity and the annual generation estimate from the quote
Planning and Building Regulations route, grid connection method
The contract's overall cost including VAT, checked before you submit

Paperwork done right keeps your certification healthy. Keeping the diary full is the other half. Solar Surveys UK books qualified commercial solar survey appointments with business owners for UK installers. You pay per booked appointment, with no retainer. Our commercial solar survey checklist covers what to capture on the first visit.

MCS Installations Database: FAQ

What is the MCS Installations Database?

The MCS Installations Database (MID) is MCS's central database of every MCS certified small-scale, low-carbon installation in the UK. Installers create MCS certificates in it, and MCS says DESNZ and Ofgem use its data.

Who can register an installation on the MID?

Only the MCS certified contractor that entered into the contract with the customer, and only once the installation is fully complete and commissioned. Your certification body grants your MID login, and it is revoked if you are suspended or removed.

How long do I have to register an MCS certificate?

Under the current scheme, MCS's installer guidance says within 10 working days of the commissioning date, although MID's own late-certificate prompt says 14 days. Under the redeveloped scheme the window is 30 days. Late registration is still possible, but you must give a reason and it is recorded.

How much does an MCS certificate cost to register?

MCS's step-by-step guide says the certificate price defaults to £30 excluding VAT, paid with MID credits or through the basket.

How do I change an MCS certificate after it's issued?

Edit it in MID and finish the updates, which overwrites the earlier version, then give the customer the new one. Some fields, including the address, cost, technology, project type, date the contract was signed, government incentive and Technical Supervisor, need the MCS Helpdesk. A commissioning date change is requested through MID.

Do batteries need an MCS certificate?

Battery storage is registered on MID too, with its own certificate creation guidance, and MIS 3012 is the battery standard.

Do commercial systems over 50kW go on the MID?

No. MIS 3002 covers solar PV up to a maximum DC output of 50kWp, so MCS certificates are for systems up to that size. For the Smart Export Guarantee, Ofgem says PV over 50kW and up to 5MW needs the installation certified but not the installer.

My customer has lost their MCS certificate. What do they do?

They should ask you first, as the installer. MCS only issues a copy if the installer is no longer MCS certified or no longer trading. Its fee is £30 plus VAT, and only the current system owner or their legal representative can ask, with proof of address.

Sources

Checked 13 Oct 2026. MCS's own guidance, standards and step-by-step guides, and Ofgem's Smart Export Guarantee guidance. MCS updates MID regularly, so check the current guides in your MID account.

MCS certification for solar installers
How to get and keep MCS: standards, certification bodies, costs.
MIS 3002 explained for solar PV installers
The MCS solar PV standard, from design to handover.
G98 explained for installers
The 16A-per-phase limit and DNO notification.
G99 application for commercial solar
The forms, the DNO steps and timescales.
How to become a solar installer in the UK
Qualifications, training routes and MCS.
Solar panels and capital allowances
What to tell commercial customers about tax relief.
Commercial solar survey checklist
What to confirm before, during and after the site visit.
Commercial solar leads
Booked survey appointments with business owners.
All installer guides
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