Surge Protection System Design Review
Review of the surge protective device scheme across an installation — whether the right device types are fitted in the right places, coordinated with each other, and with the connecting leads short enough to actually deliver the protection level they claim.
What this study establishes.
SPD inventory by type, location, protection level and status indication.
Coordination check between Type 1, Type 2 and Type 3 stages, including energy sharing.
Connecting lead length assessment, which directly adds to the effective protection level.
Verification that the protection level is below the withstand category of the equipment protected.
Overcurrent protection and disconnection arrangement review for each SPD.
Gap register with specification for any additional or replacement devices.
What the work covers.
Review of the surge protective device scheme across an installation — whether the right device types are fitted in the right places, coordinated with each other, and with the connecting leads short enough to actually deliver the protection level they claim.
Connecting lead length is the most common defect. The inductive voltage developed along long leads adds directly to the device's protection level, and a well-chosen SPD on half a metre of lead can deliver a let-through voltage far above what the equipment can survive.
What lands in your inbox.
SPD inventory by type, location, protection level
SPD inventory by type, location, protection level and status indication.
Coordination check between Type 1, Type 2
Coordination check between Type 1, Type 2 and Type 3 stages, including energy sharing.
Connecting lead length assessment, which directly adds
Connecting lead length assessment, which directly adds to the effective protection level.
Verification that the protection level is below
Verification that the protection level is below the withstand category of the equipment protected.
Overcurrent protection and disconnection arrangement review for
Overcurrent protection and disconnection arrangement review for each SPD.
Gap register
Gap register with specification for any additional or replacement devices.
How we run it.
Scope & data capture
We confirm the question the study must answer, agree the measurement or modelling points, and collect what the work depends on: distribution drawings showing existing spd locations; lightning protection system design and the structure's risk classification; equipment impulse withstand ratings for the load being protected.
Measurement & modelling
Engineers carry out the measurement and modelling on site and in software, under operating conditions representative of the problem rather than a single convenient snapshot.
Analysis against standard
Results are assessed against IEC 61643-11, IEC 61643-12, IEC 62305-4, with the assessment basis and any measurement uncertainty stated rather than implied.
Report & recommendations
You receive a signed engineering report with findings ranked by consequence, the reasoning behind each conclusion, and mitigation options costed so they can be acted on or deferred deliberately.
Assessed against the published limits.
Common questions.
Typically in one of these situations: equipment damage after storms despite spds being installed; new installation where the spd scheme needs independent verification; spd status indicators showing end of life, or devices never inspected since installation. If none of these apply, the study is unlikely to be the right next step and we will say so.
To scope and run the work we need distribution drawings showing existing spd locations; lightning protection system design and the structure's risk classification; equipment impulse withstand ratings for the load being protected. Where any of it is missing we can establish it on site, which changes the scope rather than blocking the work.
Primarily IEC 61643-11, IEC 61643-12, IEC 62305-4, IEC 60364-5-53. The applicable framework depends on your connection agreement and jurisdiction, so we confirm which applies before measurement rather than after.
Ready to start the engagement?
Tell us about your site and the problem you are seeing. We come back with a fixed scope, a fixed fee, and a named lead engineer.