A1 Certificate in Practice: Installation Work in the EU

This article offers guidance drawn from installation practice. It is not legal advice, and the reporting rules change regularly. Check the current requirements before every assignment.

What the A1 certificate is — and what it is not

The A1 proves one single thing: that the person remains covered by social insurance in their home country and does not have to be insured in the country of assignment.

What it is not:

• Not a work permit
• Not a registration in the destination country
• Not a tax arrangement
• Not a substitute for a professional ID card on site

The most common misconception is: "We have the A1, so everything is sorted." That is wrong. The A1 is the foundation, not the whole package.

For whom, how often, for how long

For every person who travels. The journeyman, the temporary fitter, the boss who only drops by briefly. Each one needs their own.

For every assignment. Even for a single day. There is no minimum threshold.

For the self-employed too. Anyone travelling as a sole trader without employees applies for an A1 for themselves.

Per country. If an assignment passes through several countries or covers several countries one after the other, that has to be covered.

Applying: electronically, and with lead time

The application is made electronically — via the payroll software or the German social insurance reporting portal (SV-Meldeportal), addressed to the responsible health insurance fund. The self-employed apply to the body responsible for their insurance status. A paper application is no longer permitted.

The point where it gets stuck in practice: the A1 does not arrive immediately. Anyone applying on Friday for Monday will generally not have it on Monday.

For a planned roll-out this is not a problem — the dates are fixed weeks in advance. For a short-notice enquiry, it is the reason a team gets turned down. Anyone who regularly works abroad applies ahead of time, as soon as the order is confirmed, not when the vehicle is being loaded.

Obligation to carry: the paperwork belongs in the vehicle

During an inspection, the A1 must be available on site — on paper or retrievable digitally. A folder in the office is no use to anyone when the inspectors are standing on the site.

What happens if it is missing: fines generally fall on the employer. But the real problem is a different one — the assignment can be stopped. Then the team stands idle, the client has an empty floor, and the deadline collapses. That is why clients ask for these documents before they award an order.

What is additionally required — country by country

This is where the real effort lies. The reporting portals have different names everywhere, and the deadlines differ.

France. Posting declaration via the SIPSI portal, before the work begins. In addition, a representative in France must be appointed who can be reached during an inspection and speaks French. For construction work — which includes interior fit-out — the Carte BTP is added: a personal professional ID card that must be carried on site. It is applied for after the SIPSI declaration and is valid for posted employees for five years.

Austria. ZKO declaration before work starts, electronically with the Federal Ministry of Finance. There is no minimum duration — even a short assignment must be declared. For repeated assignments for the same client, framework declarations are possible. Anyone who fails to declare risks substantial fines.

Switzerland. Notification procedure via an online portal. In the construction sector, notification is required from the first day — the eight-day rule that otherwise applies does not apply there. In addition, a quota of 90 working days per calendar year applies. The advance notification period must be observed; short-notice assignments are particularly tricky here.

Belgium. Declaration via Limosa. The Limosa-1 certificate must be available for presentation to the Belgian client before the work begins.

Luxembourg. Registration via the e-Detachement platform with the labour inspectorate ITM.

The Netherlands, Italy, Denmark and others each have their own systems with their own deadlines.

An EU-wide uniform reporting platform is in the works, but it does not yet replace the national obligations. Check what currently applies before every assignment.

Who declares: client or subcontractor?

Clear answer: the employer posts its own people. Whoever employs staff declares that staff. As a subcontractor, you declare your fitters — not your client.

The reason is simple: only you have the data. Names, social insurance numbers, contracts, payslips. No client can do this for you, and none is allowed to.

What this means for you: for an enquiry from abroad, the question of A1 and declaration belongs in your own calculation — time, lead time, effort. Anyone who only realises this once the order has been accepted has either a time problem or a legal problem.

Checklist before an assignment abroad

• A1 certificate for every person travelling, applied for in good time
• Posting declaration in the destination country, before the first working day
• Professional ID card, if required (e.g. Carte BTP in France)
• Local representative, if the country requires one
• Identity documents of everyone travelling
• Employment contracts and proof of pay, if requested during an inspection
• Working time records — several countries require them on site
• Proof of public liability insurance
• All documents in the vehicle, not in the office

Why clients ask about it

During an inspection, the whole assignment hinges on the paperwork. If it is missing, the team can be sent off the site — and then the floor stands empty, and the client's deadline collapses. On top of that, in several countries clients share responsibility for their subcontractors on construction work.

For installation teams, this is an opportunity. Assignments abroad are the ones that most often fail because of the paperwork. Anyone who has A1 and declaration under control and is available at short notice is the first to be asked for these projects.

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