Guide
G98 and G99 forms explained, form by form
The ENA publishes a set of forms with Engineering Recommendations G98 and G99. Here's what each one is for, when you need it, where to download it, and how CircuitHQ fills them in from the job.
- G98 Forms A, B, C and D
- G99 fast track: A1-2, A3-2 and A3-3
- G99 Type A: A1-1, A1-3, A2-4, A3-1 and A3-4
- Where to download the current forms
Doing your own system? The Homeowner DNO Pack (£100 incl VAT, Great Britain only) fills in a G98 or G99 pack for you to send. It covers Type A systems only (under 17kW single phase and under 50kW), and DNO fees aren't included.
Homeowner DNO PackWhere to download G98 and G99 forms
- The ENA keeps all the G98 and G99 forms on its Engineering Database. They're listed as "EREC G98 Application Forms" and "EREC G99 Forms", and they're free to download
- Most DNOs also publish the forms on their own websites, and some have their own versions or online application tools. Check your DNO's site before you start, as they may prefer their own
- Forms change when the standards are updated, so download a fresh copy and check the current issue with your DNO
We link to the ENA rather than hosting copies, so you always get the current version.
G98 forms (up to 16A per phase, fully type tested)
G98 is for fully type-tested micro-generators up to and including 16A per phase. Check the current issue of the G98 forms with your DNO.
G98 Form A: application for multiple premises
Used before you install when you're putting micro-generators on several premises in the same close area. The DNO assesses it first, and you can only connect once it's approved. CircuitHQ fills it in.
G98 Form B: Installation Document
The notification for a single premises, sent to the DNO no later than 28 days after commissioning, counting the day of commissioning. On a multiple-premises job you send one Form B for each premises. CircuitHQ fills it in.
G98 Form C: Type Test Verification Report
The manufacturer's type test evidence. You don't usually need it if the device has a manufacturer's reference number on the ENA type test register. CircuitHQ doesn't fill this one in.
G98 Form D: decommissioning confirmation
Used when a micro-generator is permanently taken out of service. CircuitHQ fills it in.
G99 fast track forms (small, fully type-tested systems)
G99 has three Small Generation Installation (SGI) procedures for small installations where everything is connected through fully type-tested inverters. Which one applies depends on the ratings, and SGI-2 and SGI-3 can need a G100 export limitation scheme. CircuitHQ fills in all three of these forms.
G99 Form A1-2: fast track application
Application for connection of Fully Type Tested Generation under the Small Generation Installation Procedures, used for SGI-2 or SGI-3. It includes the manufacturer's reference number from the ENA type test register. The planned commissioning date has to be between 10 working days and 3 months after you apply.
G99 Form A3-2: SGI-2 and SGI-3 notification
The installation notification sent after commissioning under SGI-2 or SGI-3, no later than 28 days after commissioning, with any G100 commissioning sheets.
G99 Form A3-3: SGI-1 notification
SGI-1 is notification only, for installations within its limits. You install and commission, then notify the DNO on Form A3-3.
G99 Type A forms
For anything that doesn't fit G98 or a fast track procedure, you apply to the DNO before installing and wait for their answer.
G99 Form A1-1: application
Application for connection of power generating modules with a total aggregate capacity under 50kW three phase or 17kW single phase. It's the form most people mean by "G99 application" on a domestic or small commercial job. CircuitHQ fills it in.
G99 Form A1-3: shared output application
The A1-1 equivalent where the output is shared between two or more customers. CircuitHQ fills it in.
G99 Form A3-1: Installation Document
The installation document for Type A power generating modules, completed once the installation is commissioned. A3-4 is the version where the output is shared between two or more customers. CircuitHQ fills in both.
G99 Form A2-4: site commissioning tests
The site compliance and commissioning test requirements for Type A modules, including the interface protection tests. CircuitHQ fills it in.
G99 Forms A2-1, A2-2 and A2-3: compliance verification reports
A2-1 and A2-2 are for synchronous and asynchronous (non-inverter) modules, up to and over 50kW. A2-3 is for Type A inverter-connected modules and comes from the manufacturer. CircuitHQ doesn't fill these in: where a device isn't on the ENA register, it asks you to attach the manufacturer's A2-3.
Standard Application Form (Type A, 50kW or more)
For Type A installations of 50kW or more three phase, or 17kW or more single phase, the DNO's Standard Application Form is used. CircuitHQ prepares the data for Parts 1 to 3, up to 1MW.
Decommissioning, bigger systems and export limitation
- G99 Form D1: power generating module decommissioning confirmation. CircuitHQ fills it in, as it does G98 Form D
- G100: CircuitHQ fills in the export limitation scheme application details, and the Appendix B commissioning tests where the capacity is over 3.68kW
- Type B (Forms B2-1, B2-2 and B3) and Type C and D (Forms C2-1, C2-2 and C3) are for much larger modules. CircuitHQ doesn't prepare these
- At 1MW or more, CircuitHQ shows Refer to DNO. Talk to the DNO early
How CircuitHQ sends them
Fills them from the job
The customer, site, devices and commissioning details come from the job and your device library. It flags anything missing, and works out the DNO from the MPAN, which you can change.
Looks up the ENA register
It searches the ENA register for inverters, batteries and other generation devices, and fills in the ENA reference, compliance status, kW, phases and G98/G99 type-test status where the field is blank, for you to check.
Submits eligible applications
For G98 and G99 solar and battery applications where every device is on the ENA device register, including export-limited (G100) setups, and EV chargers, under 17kW per phase, you review the application and press Submit to send it to ENA Connect Direct from the app, including G100 export-limited setups. You can amend a solar or battery application under the same ENA reference, and send the commissioning details when ENA is ready for them.
Emails the rest from the job
For 17kW or more per phase, Standard Application Form jobs, non-domestic installs and decommissioning (Form D and D1, which ENA Connect Direct doesn't cover), you can email the DNO pack to the DNO from the job, after checking the email, or send it yourself. Nothing is emailed until you press Send.
Always a PDF pack
The same forms are always available as a prepared PDF DNO pack, whichever way you send them.
Tracks every application
DNO applications have their own menu with a dated history. ENA applications have their status checked about every 4 hours, with a Refresh status button. The countdowns are a guide, not official DNO deadlines.
Your customer can e-sign the DNO Letter of Authority on their phone, and the signed PDF goes into the DNO pack. CircuitHQ prepares the forms in the ENA layout, but they aren't ENA documents, and the DNO decides whether to accept a connection.
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Questions
Where can I download the G99 forms?+
The ENA publishes all the G98 and G99 forms on the ENA Engineering Database at ena-eng.org, free of charge. Most DNOs also link to them, and some have their own versions or online tools, so check your DNO's website too.
What is G99 Form A1-1?+
Form A1-1 is the G99 application for connection of power generating modules with a total aggregate capacity under 50kW three phase or 17kW single phase. You send it to the DNO and wait for their answer before installing.
What is G99 Form A1-2?+
Form A1-2 is the fast track application for fully type-tested generation under the Small Generation Installation procedures SGI-2 and SGI-3. All the generating units, including batteries, have to be connected through fully type-tested inverters, and SGI-2 and SGI-3 can need a G100 export limitation scheme.
What is G99 Form A3-1?+
Form A3-1 is the Installation Document for Type A power generating modules, completed after commissioning on a standard G99 connection. On the fast track, the notification after commissioning is Form A3-2 instead.
What's the difference between a G98 notification and a G99 application?+
Under G98 you notify the DNO on Form B within 28 days of commissioning, for fully type-tested kit up to 16A per phase. Under G99 you apply first, on Form A1-1 or the fast track Form A1-2, and wait before installing. Our G98 vs G99 guide explains which applies.
Do I need G98 Form C?+
Usually not, if the device has a manufacturer's reference number on the ENA type test register. Form C is the type test verification report, provided where that reference isn't available. CircuitHQ doesn't fill in Form C.
Which forms does CircuitHQ fill in?+
G98 Forms A, B and D; G99 Forms A1-1, A1-2, A1-3, A2-4, A3-1, A3-2, A3-3, A3-4 and D1; the data for the Standard Application Form Parts 1 to 3 on Type A jobs up to 1MW; the G100 export limitation details and Appendix B tests; and the Letter of Authority. It doesn't fill in G98 Form C, G99 A2-1, A2-2 or A2-3, or anything for Type B, C or D.
Is there DNO application software that fills in G98 and G99 forms?+
CircuitHQ prepares G98, G99 and G100 forms from the job. For G98 and G99 solar and battery applications where every device is on the ENA device register, including export-limited (G100) setups, and EV chargers, under 17kW per phase, you review the application and press Submit to send it to ENA Connect Direct. Anything else, including 17kW or more per phase and decommissioning, can be emailed to the DNO from the job after you check the email, or sent yourself. It's included on every plan.
More from CircuitHQ
Sources, checked 4 Nov 2026 (CircuitHQ form coverage confirmed 5 Nov 2026): ENA's All G98 and G99 forms page and the ENA Engineering Database; EREC G98 (check the current issue with your DNO); the SP Energy Networks application forms page; National Grid Electricity Distribution's fast track (G99) page and Form A1-2. G98, G99, G100 and ENA Connect Direct are Energy Networks Association documents and services. CircuitHQ isn't endorsed by the IET, NICEIC, NAPIT, MCS, the ENA or any DNO.