the journal
news & guides
Product updates, playbooks and field notes for renewable installers quoting with Solar Engine.
DNO applications by size: the UK guide from G98 to Type D
Which DNO application a solar or battery job needs, by size. G98, the SGI lanes, Form A1-1, the Standard Application Form and Type B, in one table.
G98 explained: solar under 16 A per phase, connect and notify
What EREC G98 covers (3.68 kW single-phase, 11.04 kW three-phase), the 28-day notification, the Connect Direct cut-out photo, and what pushes a home into G99.
SGI-1, SGI-2 and SGI-3: G99 for bigger home inverters
The three Small Generation Installation lanes in EREC G99 Issue 2. Units up to 32 A, set down or export-limited, and when a 5 kW hybrid connects and notifies.
G99 Form A1-1: the short application under 50 kW
Who uses Form A1-1 (under 50 kW three-phase or 17 kW single-phase), what it asks for, the wait, and the Form A3-1 sign-off after commissioning.
50 kW to 1 MW: the G99 Standard Application Form
From 50 kW the short forms stop. What the SAF asks for (Parts 1 to 3), the offer clock, fees, witness tests, HV connections and the sign-off, up to 1 MW.
Above 1 MW: G99 Type B, C and D connections
What changes at 1 MW under G99. The Type B, C and D thresholds, the compliance document, witnessed tests, studies, SCADA and the 5 MW transmission step.
Before the DNO application: operator, MPAN and what counts
The facts every DNO application needs before the form. The operator, the MPAN, phases, the cut-out, batteries, existing solar, set-downs and headroom.
MCS's three new business roles, in plain English
What the Licensee, Main Contact and Technical Supervisor actually are, why the Technical Supervisor is now tied to each installation, and what to do next.
Why Connect Direct escalates your G99 application
On one platform's data, over 60% of Connect Direct applications escalate to manual review and 0.6% auto-approve — what triggers it, and what you control.
Do you still need RECC or HIES under the new MCS scheme?
Consumer Code membership becomes voluntary once you transition to the redeveloped MCS scheme. What that changes, what it doesn't, and what to check first.
Zero export, G100, and why the DNO still said no
An export limiter set to zero does not mean zero network impact. Why the intuition fails, and what to do when the reinforcement quote lands.
Estimated maximum demand and cut-out rating: two guessed fields
What the two DNO application fields actually ask for, why "just use the cut-out rating" is wrong, and what to do when nobody has published the method.
The performance estimate is now its own MCS standard
MCS has lifted system performance estimates into their own named standard family. What that changes about how you produce, evidence and store the number.
Roof loads, MCS, and when you need a structural engineer
Why installers keep asking if roof loads need a structural engineer, what a defensible record contains, and who can actually answer that question.
The 14-day MCS certificate rule and where the trail breaks
Why 14 days is generous when the commissioning data is captured on the day, and impossible when it is reconstructed three weeks later.
The clause 5.5.5 flat-roof deadline was 10 November, not August
MCS withdrew the clause 5.5.5 route for flat roofs. The deadline moved to 10 November 2025, not August — and what to check on every flat-roof quote now.
UK solar design software: what actually matters
Most solar design tools grew up in markets with different paperwork. What a UK installer should evaluate on instead, and the gap no tool yet spans.