The Type of SPD and Their Difference

There will be an inrush current from the electrical network or the lightning strike, electrostatic discharge, electromagnetic pulse, or disruption in the power grid can also lead to an over voltage which increases the failure ratio of lighting fixtures, that’s why we need a device that can absorb part of the over current to protect the light, this is the Surge protection device.  

Types of SPD and their difference

There are mainly two kinds of SPDs, parallel-connected and series-connected, the difference between the two series is determined by the internal circuit itself,  most of our lamps use parallel-connected SPD. however, both solutions have SPD degradation caused by A sustained over-voltage condition.

The customer is worried that the inrush current may reach the power supply first when the SPD is connected to the Power supply in parallel which causes the lamp failure, in fact, the surge will reach to SPD first in a parallel circuit, this is because the SPD inside the power supply will pass through the power supply casing, while the SPD directly passes through the electronic wires The conductive resistance of the shell should be small, so the surge will go to the SPD first. In a parallel circuit, if the lightning protector is broken, the lamp can still work normally.

The power supply will be also cut off once the SPD is damaged when the Inrush current and power supply are connected in series, which will make the whole lamp not work, some clients prefer this series connection so that they know when it is time to replace the SPD.

Lifetime of the SPD

As far as we know, there is always a sustained overvoltage that causes the SPD degradation, which means there is a lifetime limitation for the SPD, even for some SPD with an indicator that shows it is still on, the actual protection is very weak and require the professional equipment to measure it, for some applications, we strongly recommend the client to add one external SPD in the distribution box to protect the lamps more.

Please free to contact us for more details.