Step 6 of 6
Certificates and sign-off
DIY solar is legal in the UK, and we can get the electrical sign-off you need to connect safely. But be aware: getting an MCS certificate — the thing that unlocks Smart Export Guarantee payments — usually is not possible for a system you have fully bought and fitted yourself. Read on to see why, and what your options are.
Part P Building Regulations (electrical sign-off)
The consumer unit connection — connecting the inverter's AC output to your home's electrical system — falls under Part P of the Building Regulations. This work must be carried out by a Part P-registered electrician, or notified to your local authority building control before connection. We can handle this: our installer is Part P-registered and will make the final AC connection and submit the Building Regulations notification as part of the sign-off service.
DNO notification (grid connection)
If your system is over 3.68 kW (per G98 grid connection standard) single-phase, you must notify your DNO (your Distribution Network Operator) before connecting to the grid. For systems under 3.68 kW, connection is permitted under G98 rules — your inverter must be G98/G99 certified (all modern UK-sold string inverters are). We handle DNO notification as part of the sign-off visit.
MCS certificate (for SEG payments) — the catch with a full DIY install
To receive Smart Export Guarantee payments from your energy supplier, your installation must hold an MCS certificate. The MCS installation standard (MIS 3002) does not just require an inspection — it defines MCS certification as covering the supply, design, installation, and commissioning of the system by the certified installer. In practice, that means an MCS installer generally cannot inspect a system you have already bought and fitted yourself and issue a certificate for it after the fact — because they did not design, supply, or commission it. This is a rule from the certification standard itself, not just installer caution.
What we can actually offer
If you go fully DIY — sourcing your own panels, inverter, and battery, and fitting them yourself — we can still arrange the AC consumer unit connection, Part P notification, and DNO registration, so your system is safe and legally connected. What we generally cannot do afterwards is issue an MCS certificate, which means no SEG export payments.
If SEG eligibility matters to you, talk to us before you order any equipment. Some installers will treat the job as their own from the start — reviewing and approving (or supplying) the equipment and being involved in the design before installation — which keeps the MCS certificate possible. That is a different, more involved arrangement than pure self-install-then-sign-off, so it is worth confirming directly with whichever installer you use rather than assuming it is available.
Timing
If you want to keep the MCS/SEG route open, get in touch before you order panels — our installer will want to review (and possibly help source) your equipment list before agreeing to bring the job under their MCS number. If SEG payments are not a priority for you, you are free to buy and fit everything yourself and just use our Part P/DNO sign-off service.
Summary checklist
- G98/G99-certified inverter (✓ all products in this guide)
- Final AC connection and Part P sign-off — we handle this, DIY or not
- DNO (your Distribution Network Operator) notification — we handle this, DIY or not
- MCS certificate (needed for SEG) — only achievable if an MCS installer designs/supplies/commissions the job as their own; not available as an after-the-fact sign-off for a fully self-installed system — talk to us before ordering equipment if this matters to you
- MID-certified generation meter fitted (see Step 5)
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