Where To Set Up The Primary Surge Protector - Choose The Right One To Double The Effect
At present, the multi-level installation of surge protectors has the most significant protection effect in building lightning protection measures. However, the installation positions of multiple levels of SPDs are very particular, and they must be installed in the correct position. Any mistake will affect the overall protection effect. This article focuses on where to set up a first-level surge protective device.
Where to set up a first-level surge protection device, building protection measures are based on the concept of building lightning protection zones explained in Part 4 of the standard IEC 62305. Surge protectors are divided into multiple levels and installed between zones (LPZ) to achieve multiple protection effects.
The first-level SPD, with a test waveform of 10/350μs, mainly protects against direct lightning strikes, and has the characteristics of large flow rate and strong discharge capacity.
In the Technical Specification for Lightning Protection of Building Electronic Information Systems (GB 50343-2012), 5.4.3 requires that: For AC power supply lines entering buildings, at the junction of LPZ0A or LPZ0B and LPZ1 areas such as the main distribution box of the line, a surge protector of Class I test or a surge protector of Class II test should be installed as the first-level protection; at the junction of subsequent protection areas such as the distribution box of the distribution line and the distribution box of the electronic equipment room, a surge protector of Class II or Class III test can be installed as the subsequent protection.
Where to install the first-level surge protector, in addition to the main distribution box, usually in the distribution box outdoors and outside the protection range of the lightning rod, such as the main power supply incoming distribution box, the main distribution cabinet on the low-voltage side of the distribution transformer, and the distribution box of the power line that is led out to the protection range of the direct lightning protection device of the building. A primary surge protector should be installed, generally using Iimp ≥ 12.5Ka. 12.5Ka is sufficient in most cases, but the editor recommends using Iimp=20Ka or 25Ka so that there will be enough margin and the service life will be longer.
