MCS vs G98 vs Part P: What UK Solar Battery Owners Need to Know

If you are comparing solar panel or battery installation quotes, the paperwork can be confusing. One installer may talk about MCS, another may mention a G98 notification, and a third may focus on Part P sign-off. They sound similar, but they are not interchangeable.

MCS vs G98 vs Part P is best understood as three separate compliance areas. MCS relates mainly to installation quality and access to many export tariffs. G98 and G99 relate to connecting generation equipment to the electricity network. Part P is part of the Building Regulations in England and Wales, covering the safety requirements for domestic electrical installations.

Alt: MCS vs G98 vs Part P

What is the difference between MCS, G98 and Part P?

MCS certifies renewable installation quality. G98 or G99 covers the requirements for connecting solar or battery systems to the local electricity grid through the DNO. Part P is the UK home electrical safety rule for notifiable domestic electrical work.

Quick comparison at a glance

In short, the MCS vs G98 vs Part P comparison is not about choosing one. A single installation may need two or all three, depending on system design, export plans and electrical work.

Simple rule for homeowners

• MCS: Covers installation standards, consumer protection and eligibility for some export schemes.
• G98/G99: Covers notification or approval for connecting generation systems to the grid.
• Part P: Covers domestic electrical safety and Building Regulations compliance.
• Before payment: Confirm responsibilities and request all certificates after commissioning.

MCS certification and export payment eligibility

MCS certification is a quality assurance scheme for low-carbon technologies, not a grid connection approval and not a Building Regulations certificate. It tells you the installer and installation should meet recognised standards, but it does not replace DNO notification or electrical safety sign-off.

The role of MCS in renewable installations

MCS means Microgeneration Certification Scheme. For homeowners, it mainly relates to solar PV. An MCS-certified installer follows scheme standards, uses approved products where needed, and provides an MCS certificate. This helps with installation evidence, home sales, warranties, and export tariffs, but does not confirm grid connection approval.

MCS and the Smart Export Guarantee

The Smart Export Guarantee (SEG) lets licensed suppliers pay eligible customers for exported renewable electricity. Many suppliers require an MCS certificate or equivalent. Before counting SEG income, check tariff rules, meter, system size, and certification requirements. If important, ask the installer to confirm the system meets your chosen supplier’ s evidence rules.

Do you need G98 or G99 for a solar or battery system?

G98/G99 requirements may apply when solar PV, battery systems or other generation equipment connect to the public grid, depending on the system design and export capability. These are DNO safety and connection rules. They do not confirm MCS certification or Part P compliance.

• G98 for small systems: Applies to generation equipment up to 16A per phase. It is usually a notification process, with the installer informing the DNO after commissioning.
• G99 for larger or complex systems: Applies to systems above G98 limits, higher export capacity, or more complex setups. DNO approval is usually required before connection.

Key difference: G98 suits smaller installations, while G99 involves more detailed network assessment and approval.

DNO notification and approval responsibilities

Before installation, confirm whether your system requires G98 notification or G99 approval:

• Check inverter rating, battery setup and export limits.
• Confirm the correct DNO process.
• Ensure the installer handles paperwork and provides evidence.
• Keep DNO responses with your handover documents.

Part P and domestic electrical safety

Part P covers electrical safety in homes in England and Wales. For solar PV and battery systems, fixed wiring, consumer unit work, or new circuits usually require certified installation and Building Regulations approval.

Notifiable electrical work in homes

Not all electrical work must be notified. In England and Wales, new circuits, consumer unit work, may fall under Part P when they involve notifiable electrical work. Rules differ in Scotland and Northern Ireland, so ask your installer which local certification applies.

Electrical Installation Certificate and Building Regulations sign-off

The main electrical safety document is usually an Electrical Installation Certificate, confirming the work was designed, installed, inspected, and tested to wiring regulations. In England and Wales, notifiable work also needs Building Regulations compliance proof, via NICEIC, NAPIT, or local authority building control.

Do Solar Batteries Need MCS, G98 and Part P?

Solar or battery systems may need several compliance documents. MCS confirms recognised installation standards, G98/G99 shows the grid connection is approved, and Part P confirms domestic electrical work is safe, compliant, and properly certified.

Solar PV connected to a home consumer unit

A home rooftop solar PV system may involve all three: MCS for quality/export eligibility, G98 or G99 for grid connection, and Part P for connection to the home’ s fixed wiring. So,“MCS included” alone is incomplete; the quote should also cover DNO procedures and electrical certification.

Solar panels with battery storage

Solar panels with battery storage can add extra complexity, as battery inverters, hybrid inverters and backup circuits may affect whether a system falls under G98 or G99 requirements. Safe electrical design, manufacturer instructions and suitable protection should always be considered before installation.

For homeowners looking for a flexible storage option, the Anker SOLIX Solarbank 4 E5000 Pro is designed to adapt to different solar setups. Its key features include:

• 4 MPPT channels: Supports 4–12 solar panels, allowing the system to expand with changing energy needs.
• 2,500W bidirectional charging: Enables flexible energy management between solar generation, storage and household use.
• 800W grid-tied output: Helps provide power for everyday household consumption.
• Plug-and-play design: Simplifies setup for compatible installations.

Before installation, users should confirm how the battery system connects to the home electrical system and whether any DNO requirements apply.

Off-grid and zero-export setups

Off-grid systems usually do not require a standard grid connection application if they are completely isolated from the public grid. However, safety regulations still apply, and proper design and certification are required.

Zero-export systems differ: if connected to the grid, the DNO may still require notification or approval.“Zero export” does not always mean no paperwork.

Documents to request from your installer

The best time to discuss solar installation certificates UK homeowners should receive is before you accept a quote. A proper handover pack helps prove compliance, supports warranty claims, and avoids problems when switching export tariffs or selling the property.

• Compliance certificates: MCS certificate (if applicable), DNO G98/G99 evidence, Electrical Installation Certificate and Building Regulations certificate.
• System records: Inverter commissioning results, export settings and metering details.
• Product information: Warranties, manuals, app details and shutdown instructions.

Before completion: Ask the installer to explain any missing documents in writing.

What should you check before accepting a quote?

Before accepting a solar or battery quote, check the installer’ s credentials, the proposed system size, export plans, DNO process and Part P responsibilities. These details can affect payment eligibility, installation timescales and the documents you receive after commissioning.

• Installer credentials: Verify MCS certification, electrician qualifications and certificate details.
• System size and export plans: Confirm expected generation, export limits and whether G98/G99 requirements apply.
• Responsibilities and paperwork: Ensure the quote clearly states who handles DNO applications, Building Regulations compliance and final documents.

Summary

MCS vs G98 vs Part P is easiest to understand as a three-part compliance picture. MCS supports installation quality and many export tariff applications. G98 or G99 deals with the local electricity network. Part P deals with safe domestic electrical work and Building Regulations evidence in England and Wales.

Before you proceed, confirm your system size, export plans and battery configuration. Ask whether the project falls under G98 or G99, whether the installer is MCS-certified where needed, and how the electrical work will be signed off. Request a written list of completion documents before accepting a solar or battery quote, so you know exactly what you will receive when the work is finished.

FAQ

Is MCS legally required for solar panels in the UK?

No, MCS is not generally a legal requirement for installing solar panels in the UK. However, MCS certification is often required by export tariff providers and can provide useful evidence of installation standards. You may still need DNO notification and electrical safety certification even if MCS is not used.

Who submits the G98 notification to the DNO?

The installer or electrical contractor normally submits the G98 notification to the Distribution Network Operator. For small compliant systems, this is often done after commissioning within the required deadline. Ask for written confirmation and a copy of the acknowledgement for your records.

Is Part P required for solar PV and battery storage?

Part P may be required where solar PV or battery storage involves notifiable electrical work in a domestic property in England or Wales. This can include new circuits or consumer unit work. A registered competent person can usually certify the work and issue Building Regulations compliance evidence.

Can I install solar panels without an MCS installer?

Yes, it is possible to install solar panels without an MCS installer, but it may limit access to SEG payments and make documentation harder. You must still consider DNO requirements and electrical safety certification. For most homeowners, using properly accredited professionals reduces compliance and handover risks.