25 August 2026
Not every electrical contractor may sign off its own work. What the NIV keeps apart, where the register is, and why independence is the heart of the matter.
The question usually comes from the customer and sounds harmless: «Couldn't you just sign it off yourselves while you're at it?»
Sometimes yes. Often no. And the distinction is not a formality; it is the reason the periodic inspection exists at all.
Under the NIV (Low-Voltage Installation Ordinance), the safety certificate (Sicherheitsnachweis) is issued — depending on the type of installation — either by an independent inspection body or by an accredited inspection agency, and only once the installation is free of defects.
The word that matters is independent. The inspection is a check by someone with no interest of their own in how the work was done. A contractor that inspects its own installation and issues itself the certificate is checking its own work — which is exactly the arrangement the ordinance sets out to rule out.
Anyone holding an inspection licence from the ESTI (Federal Inspectorate for Heavy Current Installations) is listed in a public register: esti.admin.ch, under the licence registers, by person and by firm.
That is the list that counts — not what a website says about itself. For an owner, it is the simplest way to check that the inspection body they have commissioned is actually authorised; for a contractor, it is where to send a customer whose installation it may not sign off itself.
The ESTI advises owners to commission an inspection body promptly after receiving the request, so that the safety certificate can be submitted within the deadline.
In practice, «promptly» means earlier than it feels necessary. Between commissioning and certificate there are at least four steps — appointment, inspection, remedying any defects, follow-up inspection. On a property nobody has looked at for twenty years, the third step is rarely empty.
And responsibility for the deadline stays with the owner, even after he has commissioned someone — the ESTI is explicit on this point. A contractor who sets that expectation straight with the customer early on will have a different conversation later. More on this in the article «The deadline for the safety certificate has passed».
An inspection job is rarely just an inspection job. The defect list it produces is a quote that has written itself: specific items on a property the contractor knows, with a deadline that forces the decision anyway.
Provided it does not get lost. A defect list sitting as a PDF in an email thread cannot be found three weeks later; the same list attached to the installation's file is the starting point of the next conversation with the customer.
Who bears the costs when a defect list turns into a spot check or a missed deadline is set out in the article «Defect list and follow-up inspection: who bears the costs».
Which inspection interval applies to a property in the first place is shown by the inspection interval calculator — including the cases where the annex to the NIV gives no clear answer and the inspection body or the grid operator decides.
For a newly built or altered installation, the same role goes by another name: there it is the acceptance inspection, carried out by an independent inspection body — and expressly not by the contractor that did the installation. The difference from the periodic inspection and from the contractor's in-house final inspection is set out in the article «Initial verification, final inspection, acceptance inspection».
An inspection job can also become necessary outside the current inspection interval: when a property changes owner, that triggers, under certain conditions, an inspection duty of its own, regardless of the regular expiry date. Which changes of ownership count is set out in the article «Change of ownership and periodic inspection».
Source: Federal Inspectorate for Heavy Current Installations ESTI, information sheet «Periodische Kontrolle der elektrischen Installationen» (periodic inspection of electrical installations), October 2017. This article is not legal advice.
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