18 September 2026
A photovoltaic system passes through five bodies: grid operator, building authority, inspection body, Pronovo and — from 50 kW — ESTI. Which notification is due when, what it presupposes and what it blocks if it is missing: connection request, installation notice, completion notice, safety certificate, acceptance inspection, certification, one-off remuneration.
A PV system is registered in this order: first the technical connection request (TAG, Technisches Anschlussgesuch) to the grid operator; once that is approved, the installation notice, and in parallel the notification to the building authority; then the system is built, with an initial verification during construction; after the final inspection, the completion notice, the meter order and the safety certificate go to the grid operator, which fits the meter and commissions the system; within six months comes the acceptance inspection by an independent inspection body; only the completed system can be registered with Pronovo for the one-off remuneration, and for that its system data must be certified. The grid operator reports systems from 50 kW to ESTI. Whatever is missing blocks the next step: no approved TAG, no installation permit; no safety certificate, no commissioning; no certification, no one-off remuneration.
The order does not come from a single set of rules but from four: the NIV (the Low-Voltage Installation Ordinance) and the ESTI directives for safety, the grid operators' technical connection rules (Werkvorschriften) for the grid connection, spatial planning law for the construction, and the Energy Promotion Ordinance for the one-off remuneration. Each body knows only its own part. The electrical contractor is the only one that sees all five — and in practice the one that fills in most of the forms, even if the owner signs them.
The steps, in the order in which each presupposes the last:
Technical connection request (TAG) to the grid operator. Before anything else. The form is the same throughout Switzerland (VSE, version 2023, on werkvorschriften.ch) and, for an energy generation system, asks for the manufacturer and type of the inverters, the AC output in kVA, the DC output in kWp and the "maximum power fed by the generation system into the distribution grid, including output already installed and any installed energy storage with feed-back". The grid operator checks whether its grid can take the feed-in and, where necessary, orders grid measures, which it quotes to the owner. The approved request "is valid for 1 year or as specified by the DSO".
Installation notice to the grid operator. Energy generation systems and energy storage are on the list of notifiable work in ESTI directive 221, regardless of output. The notice is submitted after the TAG has been approved — the form says so expressly: "The installation permit is granted with the approval of the installation notice submitted." Without an approved notice, work may not begin. What the notice is and who signs it is covered in the article "Installation notice".
Notification to the building authority. Solar systems on roofs that are "sufficiently adapted" are exempt from a permit under Art. 18a of the Spatial Planning Act and go only through the municipality's notification procedure; systems on cultural and natural monuments still need a building permit. This runs in parallel with the first two steps and is the owner's business.
Construction with initial verification during construction. Art. 24 para. 1 NIV requires a documented initial verification before commissioning; its content follows from chapter 6.1 of the NIN (the Swiss low-voltage installation standard). For PV systems, ESTI recommends the "Photovoltaic measurement and test report", which covers the DC side according to EN 62446-1 and is attached to the safety certificate.
Final inspection and safety certificate. Before handover, a qualified person or a person authorised to inspect carries out the final inspection and issues the safety certificate (Sicherheitsnachweis; Art. 24 paras. 2 and 4 NIV). Holders of a limited installation permit do not issue one; a Solarteur (a certified solar installer) who builds the DC side hands the owner the report of the initial verification.
Completion notice and meter order to the grid operator. Together with the safety certificate. The grid operator fits or replaces the meter, accepts the system and releases the feed-in — the first commissioning is carried out by the grid operator, not by the installer. Some grid operators carry out an on-site acceptance for this and then conclude the producer contract for the feed-in tariff.
Acceptance inspection within six months. For an energy generation system connected to the low-voltage distribution grid, the owner arranges "an acceptance inspection by an independent inspection body or an accredited inspection body within six months" and submits the safety certificate to the grid operator within that period (Art. 35 para. 3 NIV). This is the inspection many owners forget, because the system has long been running.
Notification to ESTI — by the grid operator. Since 1 July 2021, an energy generation system on the low-voltage grid no longer needs plan approval from ESTI. Instead, the grid operator reports the completion to ESTI "within 14 days of receipt of the safety certificates" (Art. 33 para. 1bis NIV), under directive 220 for systems with an active power from 50 kW or 55 kVA. ESTI then carries out spot checks. The contractor does nothing here, but needs to know that its system is on file with the Inspectorate.
Certification of the system data. A precondition for the one-off remuneration and for guarantees of origin. For PV systems under 100 kW, the grid operator, an inspection body or an accredited auditor may certify, provided the body is "not legally connected" to the operator; from 100 kW, only an accredited auditor. The certification "must be carried out at the location of the production system". Some grid operators certify only up to a limit of their own — Primeo Energie, for example, up to and including 30 kVA.
Application for one-off remuneration with Pronovo. For systems under 100 kW (KLEIV, the one-off remuneration for small systems) the rule is: "KLEIV applications can only be submitted once the system has been completed." Attached are the grid operator's acceptance report or, failing that, the safety certificate and the measurement and test report, a land register extract that is "not older than one year at the time of registration", the payment details and, for integrated systems, three photos. Systems from 100 kW (GREIV, the one-off remuneration for large systems) "can be submitted before completion". The application goes through the Pronovo customer portal, including by the installer — with the operator's written power of attorney. Why the 100 kW decide the timing is explained in the article "One-off remuneration: application before or after commissioning".
The order is not a recommendation but a chain of preconditions. Four dependencies cost the most time in practice:
On top of this comes a deadline that nobody blocks and that is therefore missed: the acceptance inspection within six months under Art. 35 para. 3 NIV. It belongs in the order, with a date, not in hope.
Legally, the owner is responsible for the grid connection, the safety certificate at handover and the acceptance inspection; the operator files the Pronovo application. In practice, the electrical contractor does the TAG, the installation notice, the initial verification, the final inspection, the safety certificate and the completion notice — and, with a power of attorney, the Pronovo application too. What does not fall to the contractor but still has to be organised: the building notification, the independent inspection body for the acceptance inspection, the certifying body, the land register extract.
Three things help keep the process on track:
Where the PV system meets a ZEV (a self-consumption community), a further step is added; it is described in the article "ZEV: self-consumption community".
Can the Pronovo application be filed before construction? For systems from 100 kW (GREIV) yes, for systems under 100 kW (KLEIV) no — these "can only be submitted once the system has been completed".
Does a PV system have to be reported to ESTI? Not by the contractor and not by the owner. Since 1 July 2021, plan approval is no longer required for energy generation systems on the low-voltage grid. Instead, the grid operator reports the completion of systems from 50 kW to ESTI within 14 days of receiving the safety certificate.
Who certifies a PV system? Under 100 kW, the grid operator, an inspection body or an accredited auditor, provided the body is not legally connected to the operator; from 100 kW, only an accredited auditor. The certification takes place at the location of the system.
Does the system still need an inspection after commissioning? Yes. For an energy generation system connected to the grid, the owner arranges an acceptance inspection by an independent inspection body or an accredited inspection body within six months and submits the safety certificate to the grid operator (Art. 35 para. 3 NIV).
Sources: Low-Voltage Installation Ordinance (NIV, SR 734.27), Arts. 24, 33 para. 1bis and 35 para. 3, as at 31 October 2025, fedlex.admin.ch. ESTI, directive no. 220 "Requirements for energy generation systems", version 0621, sections 6 and 8; ESTI, directive no. 221, version 0621. VSE, form "Technical connection request (TAG)", version V-2023-de, werkvorschriften.ch. Pronovo AG, "Submitting an application for a photovoltaic system", "Certifying bodies" and "The Pronovo customer portal", pronovo.ch, accessed on 18 September 2026. Swissolar, "Processes in the planning, construction and operation of PV systems", April 2018. Primeo Energie, "10 steps to your photovoltaic system", 2026. The technical connection rules and forms of the responsible grid operator are authoritative.
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