For low-voltage AC power circuits, the applicable standard is NF EN 61643-11; for telecom and signaling lines it is 61643-21; for photovoltaic DC circuits it is 61643-31. The first action on any project is confirming the exact edition referenced in your procurement documents, then pulling Uc, Up, In, and Iimp straight from the manufacturer’s test reports. Product conformity alone never proves an installation is compliant. That still depends on NF C 15-100 and a site-specific analyse du risque foudre.

TL;DR:

  • Verification of the correct IEC edition and part number is essential, as mixing standards can cause inspection failures.
  • Key parameters Uc, Up, In, and Iimp must be matched accurately to system voltage and surge energy requirements to avoid premature device failure or inadequate protection.
  • The 2024/2025 updates emphasize testing for temporary overvoltage and combined-mode protection, requiring precise matching of test reports to product configuration.
  • Installation compliance depends on site-specific lightning risk analysis and adherence to NF C 15-100, not solely on product conformity.
  • A comprehensive handover dossier must include reference standards, test reports, wiring diagrams, and verification of end-of-life indicators to ensure ongoing compliance.
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Table of Contents

Which Part of NF EN 61643 Applies to Your Installation?

The 61643 series is not one document. It is a family, and picking the wrong part is the fastest way to fail an inspection.

IEC 61643-01:2024 sits at the top as the general requirements document. It defines terms, test philosophy, and baseline safety criteria that every product-specific part references. You rarely cite it alone on a datasheet, but every downstream part assumes you have read it.

For anything downstream, the mapping is straightforward once you know the interface you are protecting. Power panels, distribution boards, and main switchboards fall under NF EN IEC 61643-11:2025, which covers AC networks up to 1,000 V. PoE switches, alarm panels, and comms racks need IEC 61643-21:2025 instead, since an AC power SPD does nothing for a data line. Photovoltaic DC strings use part 31.

NF EN 61643 parts by protected interface

Edition matters just as much as part number. A supplier quoting an older IEC edition without confirming the current French homologated reference through AFNOR is handing you a document that may no longer match the installed product’s actual test basis. On mixed sites with power, comms, and PV all present, you are not choosing one part. You are coordinating three, and the analyse du risque foudre needs to document how surge currents travel between them.

What Product Parameters Must You Verify on Every SPD?

Four letters and a handful of numbers separate a correctly specified SPD from an expensive mistake. Every datasheet review should start here.

Uc is the maximum continuous operating voltage the SPD tolerates without conducting. Set it too low relative to your system voltage and the device degrades prematurely; set it carelessly high and it may not clamp fast enough to protect sensitive loads. Up, the voltage protection level, tells you the residual voltage that reaches connected equipment during a surge. That figure has to sit comfortably below the withstand voltage of whatever you are protecting, whether that is a PLC, a server rack, or a motor drive.

In (nominal discharge current) and Iimp (impulse current, required for Type 1 devices) describe how much surge energy the SPD can absorb repeatedly versus during a direct or near-direct lightning event.

Beyond those four, check:

  • Number of poles and protection modes (L-N, L-PE, N-PE) match the earthing arrangement on site.
  • Internal disconnectors are rated for the prospective fault current, not just a generic value.
  • End-of-life indication is present and its trigger behavior is documented, not assumed.
  • Short-circuit withstand is compatible with the panel’s actual fault level.

Pro Tip:Never accept a datasheet figure without the corresponding test report. A supplier who cannot produce the report tied to the exact SPD configuration you are buying is asking you to trust a number nobody verified.

What Changed in the 2024 and 2025 Standard Revisions?

The 2024/2025 updates to IEC 61643-01 and 61643-11 are not cosmetic. They shift how much evidence you should demand before accepting a product on a project.

Temporary overvoltage (TOV) testing now gets explicit treatment, and it matters because TOV behavior depends on your earthing scheme. Ask your supplier directly: was this SPD tested for the TOV scenario matching a TT, TN, or IT system, or a generic case that may not apply to your site?

The revisions also add combined-mode protection measurements, meaning tests now capture behavior between active conductors and PE together, not just each mode in isolation. Dielectric and short-circuit clauses for electrically separated circuits got stricter too.

The practical trap is scope confusion. A test report might cover a full assembled SPD, a single protection mode, or an individual component inside it. Those are three different levels of evidence, and a “legacy” report from before the revision may not specify which one you are looking at. Insist on matching the report’s configuration to the exact product reference, edition, and annex before signing off.

How Does NF EN 61643 Interact With French Installation Rules?

NF EN 61643 tells you an SPD performs to spec in a lab. It says nothing about whether your building needs one, or where. That decision belongs to NF C 15-100 and a site-specific analyse du risque foudre (ARF), and confusing the two is one of the most common gaps between what gets specified and what gets built.

A 2025 arrêté reinforces this separation for designated sensitive installations. It requires a documented ARF, retention of that documentation, periodic verification, and defined timelines for bringing existing installations up to current expectations, alongside inspection procedures after a recorded lightning strike. New builds and existing sites are not treated identically. Existing installations in scope get a compliance window rather than an immediate mandate, but the paperwork trail starts now regardless of which category applies.

For engineering firms writing tenders, this changes what belongs in the spec. The ARF output should feed directly into the technical specification, not sit in a separate file nobody references during procurement. Require edition-specific test reports as a contract deliverable, not an afterthought, and write a maintenance and verification clause into the contract before installation begins, not after a client asks why nobody is checking the SPDs.

What Belongs in the Handover Compliance Dossier?

A commissioning report without a proper dossier is a liability waiting for an insurance claim. Attach these items before signing off:

  1. Referenced standard edition(s) for every SPD installed, matched to its specific part (11, 21, or 31).
  2. SPD identification and model number, cross-referenced to the datasheet.
  3. Documented values for Uc, Up, In, and Iimp where applicable.
  4. Manufacturer test reports tied explicitly to that edition and configuration.
  5. Wiring diagram showing SPD placement and PE connection routing.

At site verification, confirm the end-of-life indicator functions, test internal disconnectors, verify PE conductor continuity, and check labeling and repérage against the diagram. Keep a maintenance notice on file. After any recorded lightning strike, run a simplified inspection and set a remedial action timeline rather than waiting for the next scheduled visit.

Why Specifiers Keep Getting SPD Selection Wrong

The single most common mistake in SPD selection is choosing on one number. Engineers see a headline “40 kA” or “Type 2” designation and assume the job is done. It never is. Uc has to coordinate with your system voltage and insulation withstand; Up has to sit below your equipment’s tolerance; and none of it means anything if the earthing scheme on site does not match what the SPD was tested against.

Why Specifiers Keep Getting SPD Selection Wrong — overview diagram

Contract wording is where most disputes originate, and where they are cheapest to prevent. Specify the exact standard edition, not just the part number. Require sample test reports for the precise configuration being supplied, not a generic type-test summary from a different product line. Build the maintenance dossier requirement into the contract itself.

On handover, a standard short list is run every time: repérage against the wiring diagram, a functional test of the internal disconnector, a continuity check on the PE conductor, and a full documentation review before anyone signs. None of these steps take long. Skipping any of them is how a technically compliant product ends up in a non-compliant installation.

— INDELEC

Get Your SPD Installation Documented and Compliant From Day One

Coordinating Uc, Up, In, and Iimp against your site’s earthing scheme, then producing a dossier an inspector will actually accept, is a lot to carry on top of a normal project schedule. Indelec’s lightning protection services build the ARF, the technical study, and the SPD installation into a single scope, so the compliance evidence exists before the client asks for it, not after.

Indelec

Every project handover includes edition-identified test reports, a full technical dossier with datasheets and wiring diagrams, a maintenance notice, and a strike-recording setup ready to go. That covers the gap between a product that passed a lab test and an installation that passes a site inspection. Indelec also handles the earthing side directly, from deep earth grounding to surge protection supply, so the dossier reflects one coordinated system rather than parts sourced separately and hoped into compliance.

If you have a project that needs an ARF, a technical study, or SPD installation and verification, reach out through Indelec’s protection contre la foudre page to scope the work.

Sources

FAQ

What Is the French Regulation Governing Surge Protectors?

Surge protector requirements sit across two layers: product standards (NF EN 61643 for the device itself) and installation rules (NF C 15-100 plus a site-specific lightning risk analysis). A 2025 arrêté adds documented ARF, verification, and maintenance requirements for designated sensitive installations.

What Is an NF Standard?

An NF standard is a French national standard published through AFNOR, often adopted from a European (EN) or international (IEC) standard and given a homologated French reference. NF EN 61643-11 is the French adoption of the IEC 61643-11 series for low-voltage AC surge protective devices.

What Are AFNOR Standards?

AFNOR is France’s national standardization body and publishes standards through its Boutique AFNOR platform, covering everything from construction materials to electrical safety. For surge protection, AFNOR publishes and maintains the NF EN 61643 series alongside its IEC counterparts, and it is the reference point for confirming which edition currently applies.

What Standard Applies to Type 2 Surge Protectors?

Type 2 surge protectors fall under NF EN 61643-11, the same product standard covering Type 1 and Type 3 devices for AC low-voltage networks. The distinction between types comes from the test current used (In for Type 2 versus Iimp for Type 1), not a separate standard.

Does Product Conformity Guarantee Installation Compliance?

No. NF EN 61643 conformity proves the device meets performance and safety requirements in laboratory testing, but installation compliance depends separately on NF C 15-100 and a documented lightning risk analysis specific to the site.