Type 1 Surge Protection Device FAQ: 10 Most Asked Questions Answered
A Type 1 surge protection device sits at the service entrance and handles partial lightning current, but the specifications behind it confuse many installers and specifiers. This article answers the ten questions asked most often about Type 1 SPDs in a direct, quotable format. It explains what a Type 1 device actually protects against, how it differs from Type 2 and Type 3, and when installation becomes mandatory. It clarifies datasheet terms including Iimp and the 10/350 microsecond waveform, sets out where the device belongs in the distribution board, and covers backup breaker requirements. Further answers address realistic service life, how to recognise a failed unit, whether a Type 1 device can work alone without downstream protection, and which configuration suits TN-S, TN-C and TT earthing systems.
