Blogs

IEC 61643 is a family, not a single standard. Find out which part covers AC, DC, PV and signal SPDs, and what the 2025 edition of Part 11 changed.

Most SPD datasheets lead with the biggest number on the page, and for a Type 2 device that number is usually Imax. Of all the SPD parameters printed on the sheet, it is close to the least useful one for comparing products. IEC 61643-01:2024 lists Imax at item 28 of its marking and information list, worded “if declared by the manufacturer”, while item 6 requires a Type 2 SPD to declare In in

Verify a surge protection device certificate against its model, ratings, test report and issuing database before placing an order.

How a lightning protection system works end to end: IEC 62305 zones, air terminals, earthing, and the SPDs that limit surges reaching your equipment.

How does a lightning conductor work? Follow the current from the rooftop air terminal through bonding and down conductors to earth.

Solar DC SPD connection diagram done right: parallel PV+/PV- to earth, U-type vs Y-type, where to install it, and the lead-length rule that matters.

Choose industrial surge protection by voltage, SPD type, installation point and surge rating, with IEC 61643-11 product examples.

SPD coordination explained from IEC 61643-12: what the 10-meter rule really means, how to match Up across stages, and when Type 1+2 SPD solves it.

A lost neutral can push up to 400 V across your SPD. A temporary overvoltage is what it was never built to stop — how to make yours fail safely.

A lightning protection zone (LPZ) is a defined area within or around a structure where the lightning electromagnetic environment is controlled to a specific level. IEC 62305-4 divides structures into nested zones — from LPZ 0A, where direct strike exposure is uncontrolled, to LPZ 2 and beyond, where sensitive electronics operate in a fully attenuated environment. The SPD type at each boundary depends on the threat crossing it: Type 1 at LPZ

SPD and circuit breakers protect against different threats. Learn how they coordinate, which SCPD to choose, and the correct installation order in a panel.

If you’re sourcing surge protective devices to sell under your own brand, you need an OEM SPD manufacturer who builds to your spec, ships on your timeline, and stays out of your customer relationships. That’s what OEM and ODM manufacturing means in practice — and the difference between the two affects how you structure the engagement from day one. Thor Electric manufactures IEC 61643-certified SPDs for distributors, system integrators, and electrical