To sell a house with DIY solar panels you need to hand the buyer an evidence folder: the electrical sign-off for the panels, which is an Electrical Installation Certificate (EIC) plus Building Regulations evidence for the consumer-unit work; your Distribution Network Operator (DNO) connection letter under G98 or G99; any export or Smart Export Guarantee (SEG) agreement; and a component list with warranties. A self-built system cannot be MCS-certified, so this folder is what stands in for the MCS certificate a buyer’s solicitor would otherwise ask for.
I built and wired my own system and filed the DNO paperwork myself, so this is the folder I would hand a buyer. One thing to be clear about first: I am an engineer, not a solicitor or a conveyancer. A buyer’s solicitor and their mortgage lender decide what they will accept. A complete folder lets you answer their enquiries in a day instead of a fortnight; it does not overrule their judgment. This guide covers England and Wales. Scotland and Northern Ireland run different building-standards and conveyancing systems, so a Scottish seller needs a Building Standards completion certificate rather than Part P sign-off.
Jump to the part you need:
- The DIY solar sale folder
- Why a non-MCS system is a different case
- The electrical sign-off buyers care about most
- If the electrics were never signed off
- DNO connection and export paperwork
- Who actually decides: the conveyancer and lender
The DIY solar sale folder: what to gather
Assemble these before you list. Each document answers one question a buyer’s solicitor will raise about the installation. The table is the whole checklist; the sections below explain the two that cause most of the delay.
| Document | What it proves | Where it comes from |
|---|---|---|
| Electrical Installation Certificate (EIC) | The AC wiring meets BS 7671, the wiring standard | A registered electrician who made or verifies the consumer-unit connection, or the Building Control or third-party certification route |
| Building Regulations evidence | The notifiable electrical work was signed off under Part P | A competent-person scheme certificate (for example NICEIC or NAPIT), or a Building Control completion certificate |
| DNO connection letter | The network approved or was notified of your generation | Your DNO, under G98 (notify) or G99 (pre-approval) |
| Export or SEG agreement | You are paid for exported energy, and on what terms | Your export supplier, for example Octopus Outgoing on its non-MCS route |
| Component list and as-built diagram | What is on the roof and how it is wired and isolated | Your own build records |
| Product warranties | Panel, inverter and battery cover and its remaining term | Manufacturers or the retailers you bought from |
| MCS certificate | Not available: a self-build cannot be MCS-certified | None. The rows above are what substitutes for it |
If you can put your hand on the EIC and the Building Regulations evidence, most of the risk in a solar sale is already gone. The rest of the folder is quick to collect and rarely blocks anything on its own.
Why a DIY, non-MCS system is a different case
Most guidance on selling a house with solar assumes one of two things: an installer fitted the panels under MCS, or a company owns them and leases your roof. A DIY system is neither. You own the panels outright, and no MCS certificate exists, because MCS certifies registered installers and their work, not a homeowner build.
This surfaces on the standard conveyancing form. From 30 March 2026 the Law Society’s TA6 Property Information Form (6th edition) is the version conveyancers accredited under the Conveyancing Quality Scheme must use for new instructions, so on a normal sale you should expect it, and question 5.6 asks about solar panels: whether they are owned outright or leased, and, at 5.6(g), asks you to attach any Feed-in Tariff or SEG agreement together with an energy bill. For a DIY system you answer “owned outright”, which is the simple case for the buyer’s lender. What you cannot supply is an MCS number, so the buyer’s solicitor will ask for the electrical and DNO evidence instead.
The trap is letting a conveyancer treat your DIY build as if it were a leased or MCS installation, chasing an MCS certificate that can never exist while the documents that do exist sit unmentioned. Hand over the folder above up front and you set the terms of the enquiry.
The electrical sign-off buyers care about most
Connecting a solar inverter means adding a new circuit at your consumer unit. In England and Wales that is notifiable electrical work under Part P of the Building Regulations, so one of two things has to have happened at install time: a registered electrician on a competent-person scheme did the connection and self-certified it, or you notified your local authority Building Control before the work and they inspected and signed it off.
The competent-person route produces a Building Regulations compliance certificate, usually posted within about 30 days of the work. The Building Control route produces a completion certificate. Either one, paired with the EIC that shows the wiring meets Approved Document P’s safety requirement, is what a buyer’s solicitor is really after. It is the document that speaks to safety, and it is the one a lender’s valuer and a home insurer will care about too.
If the certificate is missing, treat it as a fixable compliance gap rather than a disaster, but do not assume it carries no legal weight. BS 7671 is a wiring standard, not an Act of Parliament, so wiring that falls short of it is not in itself a criminal offence. Part P is different, because it sits inside the Building Regulations: carrying out notifiable work without the required notification or certification is a breach the local authority can enforce, up to requiring the work to be altered and prosecuting under the Building Act 1984. In practice councils rarely pursue a homeowner who puts the paperwork right, and it is far cheaper to fix before you list than to discover mid-chain.
What to do if the electrics were never signed off
This is the real sticking point for DIY sellers. If you made the AC connection yourself and never notified it, and no registered electrician ever certified it, you have three routes. They trade off cost, time, and how completely they resolve the problem. Take one before you go on the market, not after a buyer’s solicitor finds the hole.
- Get the work certified now. A registered electrician can inspect and test the installation, put right anything that fails, and issue an Electrical Installation Certificate (EIC) for the work they carry out. An EIC is not the same as an Electrical Installation Condition Report (EICR): an EICR only records the condition of an existing installation on the day, so on its own it is not Part P sign-off. What clears the Building Regulations point is an electrician on a competent-person scheme certifying the notifiable work, or, in England, a registered third party assessing already-completed notifiable work. Aim to come away with an EIC plus Building Regulations evidence. Budget for around a day of an electrician’s time and get a quote first, because the cost varies by area and by how much of the cabling has to be exposed or retested. This is the cleanest fix because it settles whether the work is actually safe, not just insured.
- Apply for a regularisation certificate. Local Authority Building Control can retrospectively approve notifiable work completed after 11 November 1985. They will inspect, may require testing or exposing part of the work, and charge a fee. Fees are set by each council, usually a few hundred pounds, so check your local Building Control fee scale, and start early because turnaround depends on their inspection backlog. The authority is under no obligation to accept the application, and non-compliant work has to be put right before a certificate is issued.
- Buy legal indemnity insurance. This is the cheap route, and it is common in conveyancing: a one-off premium, often well under £100 for a risk of this size, usually arranged by your solicitor. It only covers the financial risk of enforcement. It does not make the work safe, and some lenders will not accept it where the compliance issue is unresolved. Treat it as a fallback, not the goal.
My honest read: the durable fix is proper sign-off, because it is the only one that also answers the safety question a buyer is entitled to ask. Indemnity insurance can get a sale over the line, but it leaves the next owner holding the same gap you did.
DNO connection and export paperwork
Keep the DNO letter that matches the capacity you actually connected. Under G98 you commission a system at or below 3.68 kW per phase and notify the DNO within 28 days; under G99 you apply and wait for approval above that threshold. A homeowner can file either without an installer. That letter proves the network knows about your generation; it is not an electrical certificate and it is not an export payment agreement, so keep it alongside the EIC rather than in place of it. The connection is registered against the installation at the property, so it stays with the house on a sale and the buyer does not re-notify the network.
If you are paid for export, keep that agreement too. Standard SEG tariffs expect an MCS number, so a DIY system usually reaches export through Octopus Outgoing’s non-MCS route. TA6 question 5.6(g) asks you to attach the export agreement and a supporting energy bill, so this doubles as sale paperwork. The export contract is between you and your supplier, so it does not transfer with the house: the buyer opens their own supplier account and applies for their own export tariff after completion, which is why they mainly want to see that the system is genuinely set up to export. Registering with the DNO and applying for a non-MCS export tariff are separate steps, so complete either one before you sell if you have not already.
Who actually decides: the conveyancer and lender
This folder makes the answer easy; it does not make the decision. The buyer’s solicitor raises the enquiries, the buyer’s lender decides what its valuer needs to see, and a surveyor may add their own questions. MCS matters most to lenders when a company leases the roof, because then there is a third party with rights over the property. For an owned self-build the concern is narrower: is the electrical work safe and signed off, and is the generation legitimately connected.
So do not read this checklist as a promise that any given buyer or lender will wave the sale through. Read it as the fastest way to turn a red flag into a five-minute enquiry. A complete, tidy folder handed over at the start is worth more than any single certificate produced under pressure halfway through the chain.
Frequently asked questions
Can you sell a house with non-MCS solar panels?
Yes. No law requires an MCS certificate to sell a house with solar. A DIY system cannot have one anyway. What the buyer’s solicitor wants instead is evidence the electrical work was certified under Part P and the generation was registered with the DNO, plus any export agreement. Assemble that folder and most sales proceed without the MCS chase that derails DIY installs.
Do you need an MCS certificate to sell a house with solar?
No. MCS is not a legal requirement for selling. It is the usual requirement for standard SEG export payments, but it is not what sets the 0% VAT rate: that relief applies to a qualifying installation carried out by a VAT-registered installer, not to a DIY goods-only purchase, and it is not an MCS rule. Some lenders prefer to see MCS, mainly on leased rent-a-roof systems. For an owned self-build, the electrical certificates and the DNO letter are what carries the enquiry.
Will a missing electrical certificate stop the sale?
Not automatically, but it commonly causes delay, renegotiation, or a demand for indemnity insurance. The reliable fix is to have a registered electrician inspect and certify the work, or to apply to Building Control for a regularisation certificate, before you go on the market.
Do solar panels need Building Regulations approval?
Two separate regimes apply here, and it helps to keep them apart. Planning permission is usually not needed, because most roof panels fall under permitted development, but that is a planning rule and not a Building Regulations one. Under the Building Regulations, the roof still has to carry the added load of the panels and mounting safely, and the electrical connection to the consumer unit is notifiable work under Part P that must be certified by a competent person, signed off by Building Control, or, in England, certified by a registered third party after the work is done.
Sources and first-hand context
Primary references checked while preparing this guide:
- The Law Society, TA6 Property Information Form (6th edition), which Conveyancing Quality Scheme firms must use for new instructions from 30 March 2026, question 5.6 on solar panels.
- UK Government, Approved Document P: electrical safety (Building Regulations, England and Wales).
- IET, Part P frequently asked questions on notifiable work and competent-person self-certification.
- UK Government, Building regulations approval, on applying for approval, regularising work carried out without it, and the enforcement and prosecution risk of non-compliance.
- MCS, certification scheme, which confirms that certification requires a registered installer and is not available for a homeowner build.
My first-hand contribution is a self-built, self-wired system with the DNO paperwork filed by me, and the folder I would hand a buyer from it. I am not a conveyancer, and this is not legal advice. Confirm what your buyer’s solicitor and their lender require for your specific sale.
The next move
Open a single folder today and drop in the EIC, the Building Regulations certificate, the DNO letter, your export agreement and a one-page component list with the warranty dates. If the electrical sign-off is the piece you cannot find, book an electrician or start a regularisation application now, while there is no buyer waiting on it. Do that and a DIY solar system stops being a question mark on your sale and becomes a line the buyer’s solicitor ticks in an afternoon.
