G98 is the lane most home solar has always used, and it is the only lane where the operator does not get a say before you install. Fit the system, switch it on, and tell the distribution network operator within 28 days. That simplicity has one condition, and the condition is a number: 16 A per phase.
This is part 1 of DNO applications by size. It covers what G98 includes, what you owe the operator, and the three things that quietly push a home out of G98 and into a G99 application.
The 16 A line, in kW
EREC G98 covers fully type tested micro-generators with a registered capacity up to and including 16 A per phase at 230 V. The standard does the conversion for you.
| Supply | 16 A per phase is |
|---|---|
| Single-phase | 3.68 kW |
| Three-phase | 11.04 kW |
The kW figure is worked at the nominal 230 V, whatever the voltage at the meter on the day. So a 3.6 kW inverter is G98 and a 3.68 kW inverter is G98. A 4 kW inverter is 17.4 A and is not, however small the array behind it.
Two points from the definition matter more than they look.
Fully type tested means the inverter is on the ENA Type Test Register with a G98 entry. The register is the operator's evidence that the unit's protection behaves. A unit that is not on the register cannot use G98, whatever its rating.
Per phase means the operator looks at each phase on its own. A three-phase inverter of 11.04 kW puts 16 A on each of three phases. A single-phase inverter of 3.68 kW on a three-phase supply puts 16 A on one phase and nothing on the other two. Both are G98.
One supply, one plant
Where a property has more than one inverter behind a single connection point, G98 treats the lot as one micro-generating plant. The test is the aggregate: the registered capacities added together, per phase, must stay at or under 16 A.
That is where batteries come in. A battery inverter is a generating unit, and its AC rating counts in the sum. A 3.68 kW solar inverter with a separate 3.68 kW battery inverter on the same phase is 32 A, and the property is no longer G98. It becomes an SGI lane, in part 2, or a G99 application.
Existing generation counts too. G98 says the operator will treat any additional micro-generator separately from kit commissioned under the old G83. But it also says that if the total on the supply goes past 16 A per phase, the G99 process applies and the operator must be consulted before the work is done. Ask about the old system on the survey. The feed-in tariff line on a bill and the aerial photo both give it away.
What you owe the operator
The single premises procedure is short.
- Install and commission the system. No application, no wait.
- Send the installation document, G98 Form B, within 28 days of commissioning. The 28 days include the day of commissioning. The ESQCR exemption that lets a micro-generator connect without prior consent hangs on this notice.
- Photograph the cut-out. G98 Issue 2 says an installer notifying through Connect Direct must supply a clear photograph of the cut-out so it can be checked for suitability.
Form B carries the customer's details, the MPAN, the installer's details, and a table of the micro-generators: manufacturer, model, the register reference, the registered capacity per phase, and the commissioning date. Most of it is already in your design record. The declaration is yours to sign.
The cut-out photo deserves care. It is the one input the automated route most often fails on, and a failed read costs you a second visit. We wrote about that in why Connect Direct escalates your G99 application. Take it square on, in focus, with the rating legible and a wider shot that shows where the cut-out sits.
Where the notice goes
Connect Direct is the ENA's single front door for home-sized jobs, used by every GB operator. It takes G98 and the domestic G99 lanes for properties under 17 kW per phase, and it handles the commissioning leg too. Some operators also keep their own routes: Northern Powergrid and Electricity North West take Form B by email, National Grid Electricity Distribution runs an online form, UK Power Networks has its Smart Connect portal. Any of them works. The obligation is the same: 28 days.
Northern Ireland is different. NIE Networks runs G98/NI, with its own forms and portal.
When one installer fits many
The single premises procedure stops applying when an installer plans other micro-generators within 28 days, before or after, in what G98 calls a close geographic region. That is the multiple premises procedure: a new housing estate, a street-by-street campaign, a housing association programme.
There you apply first, on G98 Form A, and connect only once the operator has approved the application and finished any network works it needs. The operator then answers on the same guaranteed-standards clock as any generation application. Each unit still gets its Form B within 28 days of commissioning. Skip this and the operator can disconnect the plant under the ESQCR, or find that a street of inverters trips on voltage rise.
What tips a home out of G98
Three things, and all three are common.
- A hybrid inverter over 3.68 kW. The 5 kW to 6 kW hybrid with a battery is the standard home sale now, and it is 22 A to 26 A on one phase. Set down to 16 A it can connect and notify on SGI-1. At full output it needs an application.
- A second system. Extra panels with their own inverter, or an AC-coupled battery added later, push the aggregate over the line even when each unit is under it.
- Generation already there. The old 4 kW array from 2012 and the new hybrid together are a G99 job, whoever fitted the first one.
The next part takes the first of those, the bigger home inverter, through the three small generation lanes.
Questions installers ask
Can I apply for 3.68 kW and fit 5 kW?
No. The declared capacity is a statement to the operator about what is connected to its network, and the installer who signs it carries it. Set the inverter to 16 A and declare the set-down, or apply for the full capacity. We covered the liability in estimated maximum demand and cut-out rating.
Does a three-phase home with three 3.68 kW inverters need an application?
Not if the inverters are on the register and each phase carries no more than 16 A. Put one unit on each phase and the site is 16 A per phase, which is G98. Put two on one phase and that phase is 32 A, which is not.
Is there a fee?
No. G98 is a notification, not a connection offer. There is nothing to quote for.
What if I forget the 28 days?
Send the Form B as soon as you notice. The operator can in principle disconnect an unnotified micro-generator under the ESQCR. In practice a late notice is far better than none, and the customer's export MPAN cannot be raised until the operator knows the system exists.
Solar Engine sizes the band from the design, not from the panel count. When the inverter, the battery and the declared existing generation add up to 16 A per phase or under, the DNO tab says G98, and the CRM's Connect Direct console files the notification from the same record.