G98 Explained: Requirements, Forms, G98 vs G99 and Plug-In Solar

G98 is the set of rules for connecting small generators, such as solar panels, to the public electricity network in Great Britain. Its formal name is Engineering Recommendation (EREC) G98. It’s published by the Energy Networks Association (ENA) and covers fully type-tested equipment up to 16 A per phase: 3.68 kW on a single-phase supply or 11.04 kW on three-phase. You fit the equipment, then tell your Distribution Network Operator (DNO), the company that runs the cables in your area, within 28 days. Anything bigger goes under G99, where you apply first.

Checked

8 October 2026

Source

The G98 Issue 2 Amendment 1 consultation draft; Ofgem's decision of 11 August 2026; IPS version 2; myplugin.solar; ENA Connect Direct; the G98 pages of the six GB network operators

Method

Each document read at source. The final Amendment 1 text needs an ENA catalogue login, so G98 wording is quoted from the draft.

What is G98?

Its full title is “Requirements for the connection of Fully Type Tested Micro-generators (up to and including 16 A per phase) in parallel with public Low Voltage Distribution Networks on or after 27 April 2019”. The current version is G98 Issue 2 Amendment 1, listed on the ENA document catalogue as August 2026. It amends Issue 2 of 10 March 2025, was approved by Ofgem on 11 August 2026, and took effect on 27 August 2026, the day SI 2026 No. 848 came into force.

G98 isn’t law in itself, but it carries weight. Ofgem describes it as “an Annex 1 document of the Distribution Code”, the code every network operator is licensed against, and the notification duty rests on an HSE exemption to the Electricity Safety, Quality and Continuity Regulations that G98 reproduces.

The scope, in G98’s own words and in plain terms:

• 16 A per phase, for the whole property. A Micro-generating Plant is “a single electrical installation that contains one or more Micro-generators” whose aggregate capacity “is no greater than 16 A per phase”. At 230 V that’s 3.68 kW single-phase or 11.04 kW three-phase. The limit is the total at the address, not per panel or per inverter.
• Fully type tested only. Ofgem: “the connection of non-type tested Micro-generators is not permitted.”
• Storage counts when it exports. G98 also applies to electricity storage, including an electric vehicle that can run in vehicle-to-grid mode, “when operating in an export mode”.
• Great Britain only. Northern Ireland uses G98/NI, a separate document. See our Northern Ireland guide.

G98 and plug-in solar: the route since Amendment 1

Amendment 1 was written to let plug-in solar connect. It defines a Plug-in Micro-generator as one with “a Registered Capacity of 800 W or less, fitted by the Manufacturer with a plug complying with BS 1363 or BS EN IEC 60309, and designed to be connected only via the Manufacturer’s plug”. Three things follow for householders.

1. You can notify yourself. “For Plug-in Micro-generator(s), the Customer may take the role of Installer.” Ofgem says the change “requires and introduces a mechanism for customers to notify DNOs”.
2. One kit per home. “Only one Plug-in Micro-generator is permitted in any given Customer Installation”, which Ofgem glosses as “effectively one per household”. IPS version 2 allows one per final circuit, but its own note says the G98 limit applies until G98 is amended, so a household may connect one.
3. Five installer rules don’t apply. No cut-out photograph, no installation wiring and isolation section, no permanently wired labelling, no installer competency requirement and no functional check on loss of mains protection. The exemptions “do not remove any requirement for the Customer’s Installation to conform with BS 7671”.

In practice you register at myplugin.solar, a site operated by Energy Networks Association Limited. You verify your email, confirm your address, choose your kit from the list of compliant devices and submit, and ENA sends the notification to your DNO. Its FAQ says “Registering your plug-in solar device is a legal requirement.” Our myplugin.solar report goes through each step.

G98 requirements

Whether it’s a rooftop array or a plug-in kit, these are the conditions.

1. The equipment is type tested and registered

G98 applies to equipment “for which a Micro-generator Type Test Verification Report demonstrates that the Micro-generator design meets all the requirements”. Testing is the manufacturer’s job, and the maker registers the product on the ENA Type Test Register under a reference number. For plug-in solar the bar is higher. IPS version 2 requires makers to “obtain confirmation that the device has been assessed and identified as compliant prior to placing them on the market”, and adds that “a device being submitted for registration shall not, in itself, be regarded as demonstrating compliance”. The device means the whole kit, not the inverter alone. As at 13 November 2026, 145 plug-in solar devices were Compliant. Check the exact model on our register tracker, not the brand.

2. The property stays within 16 A per phase

Everything at the address counts. Ofgem’s summary: plug-in kits “are permitted to connect and operate alongside other permanently wired Micro-generators provided the aggregate Registered Capacity … do not exceed G98’s existing 16 A per phase limit. Above this limit, Engineering Recommendation G99 requirements apply.” Registered capacity is the inverter’s rated output, not the panel wattage.

3. The network operator is told within 28 days

G98 is fit and notify. The installer, or for a plug-in kit the customer, must make sure the DNO knows “before the time of commissioning or no later than 28 days (inclusive of the day of commissioning) after commissioning”. Amendment 1 adds that the details “may alternatively be submitted through the Connect Direct platform”. Each operator’s page puts it slightly differently:

SP Energy Networks is the odd one out at 30 days, and its page also asks to hear about the proposal “before or at the time of commissioning”. For a plug-in kit, ENA’s registration site gives no day count and says to register once you have the device and know where it’ll be installed.

4. Several installations nearby need approval first

Fit and notify doesn’t apply where an installer plans, within the next 28 days, or has already installed, in the previous 28, other systems in a Close Geographic Region. Then the installer applies with Form A, and connection “is only allowed after the application for connection has been approved by the DNO”. A Close Geographic Region is the area fed by one low voltage feeder from one transformer, an area the DNO confirms, or premises that share a postcode once the last two letters are ignored or sit within 500 m of each other. The Amendment 1 draft adds a footnote that a landlord-led plug-in project across flats in one building is an example of this procedure, without creating new obligations on landlords.

5. The protection settings are left as made

“Fully Type Tested Micro-generators shall have protection settings set during manufacture”, and once commissioned they can only be changed “following written agreement between the DNO and the Customer or their agent”. The settings are in the next section.

G98 protection settings

G98 section 10.1, Table 2, sets the interface protection: the points at which the inverter must disconnect from the network. Values are at 230 V phase to neutral. Amendment 1 didn’t change them.

The total disconnection time is the delay setting with a tolerance of −0 s to +0.5 s. Other headline figures from section 9:

• Ride through a rate of change of frequency of up to 1.0 Hz/s, measured over 500 ms.
• Reduce output when frequency rises above 50.4 Hz, with a 10% droop.
• Reconnect only after voltage and frequency have been within the protection limits for at least 20 s.
• Power factor between 0.95 lagging and 0.95 leading.
• DC injection no more than 0.25% of the AC current rating per phase.
• Stay connected from 49.0 to 51.0 Hz indefinitely, for 90 minutes from 47.5 to 49.0 Hz or 51.0 to 51.5 Hz, for 15 minutes from 51.5 to 52.0 Hz, and for 20 s from 47.0 to 47.5 Hz.

Amendment 1 made one change in this area. Active loss of mains methods that measure impedance were previously “not considered to be suitable”. They’re now “only acceptable if they can demonstrate zero or minimal effect on harmonics and flicker”. IPS version 2 also points out that these protective functions “do not however refer to protection against electrical shock”, which is a matter for the product and the wiring.

The G98 forms: A, B1, B2, C, D1 and D2

Amendment 1 split the old Form B and Form D in two, adding simpler customer versions for plug-in kits.

The operators haven’t caught up. On 8 October 2026 SP Energy Networks and Northern Powergrid still listed the older Form A, B, C and D set, and none of the operator pages we checked offered a Form B2 or D2. For a plug-in kit, myplugin.solar does the job of Form B2. Our G98 form guide covers Form B1 field by field and what B2 asks.

G98 vs G99

G99 is the standard for anything over the G98 threshold. The practical difference is the order of events.

Electricity North West’s FAQ puts the G99 side plainly: “You will need to make a formal application for a generation connection using the ENA G99 application form”, and you “cannot operate in parallel until we have issue[d] the FON for the installation”. A plug-in kit on its own is nowhere near G99. It only becomes a G99 question when it would take a home with existing generation over 16 A per phase.

What is a G98 certificate?

G98 doesn’t contain a document called a G98 certificate. When someone asks for one, they usually mean one of three things.

1. The manufacturer’s Form C. The Type Test Verification Report, which some operator pages call a type test certificate. It carries the maker’s reference number, the technology, the capacity, a new tick box for “Plug-in Micro-generator”, the declaration “I certify that all products supplied by the company with the above Fully Type Tested reference number will be manufactured and tested to ensure that they perform as stated in this document”, and pages of test results.
2. The ENA Type Test Register entry. The product’s listing under a system reference, such as LEVOC/22218/V1/A5. Once a product is on the register, the installation document quotes the reference and Form C “does not need to be submitted”.
3. The DNO’s acknowledgement or acceptance letter. What an energy supplier usually wants for an export tariff. National Grid Electricity Distribution runs a request service for people whose supplier “has asked you to send them a DNO acceptance letter, but you don’t currently have one”.

For a plug-in kit, keep the register reference and your record of the myplugin.solar submission. Until the DNO side of Connect Direct is released, a reply from your operator is unlikely, so your own record is the evidence that you notified.

How to notify: step by step

A plug-in solar kit

1. Check the kit is Compliant on the register, by the model on its label.
2. If you already have solar, ask your DNO in writing before you plug in. Our which DNO am I with tool tells you who that is.
3. Register at myplugin.solar: email code, address, device, submit.
4. Keep a record of the submission, and register again if you move house.

A permanently wired installation

1. Your installer completes Form B1, or the operator’s online equivalent, with the equipment’s register reference.
2. They send it by your operator’s route within 28 days of commissioning (30 for SP Energy Networks). Several installations in one area need Form A first.
3. Keep the acknowledgement with your property papers. A supplier may ask for it.

G98 process by network operator

For wired installations each operator runs the process its own way. Pick yours for the form, the address and the deadline.

Northern Ireland is a separate regime. NIE Networks works to G98/NI, a different document regulated by the Utility Regulator, and the part of SI 2026 No. 848 that makes using a plug-in device lawful extends to Great Britain only. See our Northern Ireland guide.

Renters

The notification is made by whoever connects the device, so a tenant registers a plug-in kit in their own name, at the address they rent. Getting the landlord’s agreement to mount a kit is a separate question, covered in our renters’ guide.

Batteries

Amendment 1 names plug-in electricity storage, but only in anticipation of later rules. Ofgem is clear that such devices “will therefore remain prohibited from being sold, supplied, or used in the UK once DESNZ’s current proposals are implemented.” A kit with a battery built in isn’t on the plug-in route: it has to be installed conventionally by an electrician and notified like any wired system, under G98 or, if the total goes over 16 A per phase, G99. See plug-in solar and batteries.

Questions