A Distance That Needs To Be Paid Attention To When Installing A Surge Protector
GB50343 Section 5.4.6: When the line length between the voltage switch type surge protector and the voltage limiting type surge protector is less than 10m, and the line length between the voltage limiting type surge protectors is less than 5m, a decoupling device should be installed between the two levels of surge protectors.
The main reason for this standard is that multi-level power supply SPDs are installed in the power supply line. Due to the different nominal conduction voltages and nominal conduction currents of each level of SPD, the installation methods and wiring lengths are different. If the energy is not properly matched during design and installation, there will be a blind spot problem where a certain level of SPD does not operate.
In order to ensure that when the lightning high voltage pulse invades along the power supply line, each level of SPD can start the discharge in stages and avoid blind spots between multi-level SPDs, there must be a certain line distance between the two levels of SPDs (that is, a certain inductive reactance or the installation of decoupling components) to meet the requirements of avoiding blind spots. At the same time, it is required that the protection level of the final power supply SPD must be lower than the tolerance of the protected equipment to the surge voltage.
The ultimate goal of energy coordination of SPDs at all levels of power supply is to reduce the voltage and current surge values that threaten the safety of the equipment to a safe range that the protected equipment can tolerate, and the surge current discharged by SPDs at all levels of power supply does not exceed its own nominal discharge current.
GB50343 also mentioned: When the surge protector has the function of automatic energy coordination, the line length between surge protectors is not limited.
