top of page
  • Writer's pictureJaime Ventura Energy Consultant


Updated: Jul 16, 2023


Surge Protective Device SPD

Surge Protective Devices (SPD) are the solution designed to protect electrical and electronic critical loads from power surges and voltage spikes. But, it is very important to take in consideration the following aspects when choosing one:

Grounding: SPDs will be only as good as their grounding conditions. Older sites or basically facilities with inadequate wiring and grounding will not be helped by an SPD without the necessary upgrades. Even the best SPD will fail if there is no proper escape path through ground.

Listing: SPDs must have been independently designed, tested and certified to the latest editions of IEC 61643-11 and/or UL 1449 Ed. 4. This provides the user of the product with the peace of mind that they will perform safely in the application and they will also work based on the ratings provided. Both standards have strict tests that are not easy to pass, but are essential to ensure that the product is well designed for safe behavior and effective protection performance. But how can you know? The quality and performance of SPDs are difficult for a customer to assess. The correct functioning can only be verified in suitable laboratories. Apart from the external appearance, only the technical data provided by the manufacturer can serve as a guide. Even more important is a reliable declaration from the manufacturer and the certification and approval regarding the performance of the SPD and the execution of the tests specified in the respective product standard such as IEC 61643-11 or UL 1449 Ed. 4.

Location: In this case, while the ANSI/IEEE C62.41 standard has classified the critical load location environment as Categories, C (service entrance), B (distribution boards), and A (outlets), the IEC standard 62305-4 describes or categorizes critical load locations as Protection Zone Concepts called Lightning Protection Zones (LPZs). LPZs can be divided into two categories: 2 external zones (LPZ 0A, LPZ 0B) and typically 2 internal zones (LPZ 1, LPZ 2), although more zones can be introduced if required.

Coordination of SPDs: For the former two location standards, complete protection is possible when SPDs are installed in a "coordinated" manner. Coordinated SPDs means that a number of SPDs installed on a structure (from the heavy-duty SPD at the service entrance, C or LPZ0, to the SPD for terminal equipment protection A/B or LPZ2/1) must complement each other so that all transient effects of AC or DC hazardous energy are completely nullified.

We want to leave an open discussion: Is there one standard more demanding than another in terms of safety and location? Are you aware of electrical permits or local rules that may avoid using an IEC 61643-11 approved SPD in America or vice versa: UL 1449 used in Eurasia? What do you think about this information related with our model Integration Coefficient IC?

To comment back about those questions and for any additional information required, please do not hesitate to Contact Us.

42 views0 comments

Related Posts

See All


Rated 0 out of 5 stars.
No ratings yet

Add a rating
bottom of page