There are undoubtedly many instances where the installation of overvoltage protection for some or all premises is necessary for safety reasons.

Following international rules, AC surge protectors are required for most of the installations. Risk assessment methods are also available to determine more accurately the need of surge protection.

Power surges cost businesses billions annually in damaged equipment. While surge protection devices (SPDs) are critical defenses, their legal status varies globally.

However, as effective overvoltage protection may involve the installation of a number of SPDs of differing types in multiple locations within an installation, the cost of effective provision can be significant.

Moreover, it must be remembered that SPDs deteriorate to some extent whenever they are called to interrupt/divert an overvoltage until they are life expired, at which point their replacement becomes essential in order to continue to provide the level of protection deemed appropriate in the design.

For these reasons, it is important to appropriately assess when – and where within an installation – SPDs should be installed to provide the necessary overvoltage protection cost-effectively.

The performance, selection and application of AC surge protectors are defined by standards, to ensure an efficient and secure use. National standards are based on IEC international standards.

Recommendations for SPD installation

Section 4-443 of IEC 60364 «Protection against overvoltages of atmospheric origin or due to switching» recommends SPD application depending of the type of installation.

Protection against transient overvoltage shall be provided where the consequence caused by overvoltage affects:
a) human life, e.g. safety services, medical care facilities;
b) public services and cultural heritage, e.g. loss of public services, IT centers, museums;
c) commercial or industrial activity, e.g. hotels, banks, industries, commercial markets, farms.

For all other cases (dwellings, small apartment buildings), a risk assessment (based on Lightning density, Length of external low voltage lines and Environment factor) shall be performed in order to determine if protection against transient overvoltage is required.

Where SPDs Are Mandatory (By Region)

United States
- NEC 2020 Article 242: Requires Type 1 or Type 2 SPDs for new residential services (110V+).
- Critical Facilities: Hospitals/data centers under NFPA 70 must install SPDs. Relevant Keyword: “NEC 2020 SPD compliance”

European Union
- IEC 60364-5-53: Mandatory for public buildings and industrial installations since 2019.
- Country-Specific Rules: Germany (VDE 0100-443), France (NFC 15-100) enforce stricter SPD tiers.

Australia/New Zealand
- AS/NZS 3000:2018: SPDs required for solar installations, coastal areas, and structures with lightning risk.

Middle East (GCC Countries)
- UAE Fire & Life Safety Code (2021): SPDs compulsory for high-rises and smart buildings.

Asia
- Singapore: CP5 Code for data centers.
- India: IS/IEC 62305 recommends SPDs for lightning-prone zones.

Selection of the SPD

Section 5-534 of IEC 60364 «Devices for protection against overvoltages» gives the minimum performance required for SPD installed at the entrance of installation :
1 - The installation equipped with lightning rod (LPS): Recommendation : Type 1 SPD, with Lightning impulse current Iimp of 12.5 kA minimum, connected at the origin of the installation.
2 - The installation is connected to an AC network, without LPS : Recommendation : Type 2 SPD, with nominal discharge current In ≥ 5 kA, connected at the origin of the installation.

How to Choose Compliant SPDs

Certification Marks: Look for UL 1449 (US), EN 61643-11 (EU), AS/NZS 1768 (AU).
Climate Adaptation: Desert regions need SPDs rated >50°C; tropical areas require corrosion-resistant housing.
Smart Features: IoT-enabled SPDs with remote monitoring appeal to industrial buyers.