The LYSCB series surge backup protection devices produced by Lei Yuan Electric Co., Ltd. have successfully addressed the three major safety issues of surge protection devices. 

The dedicated backup protection device connected in series at the front end of the SCB protector. 

The protective function of this switch is as follows: 

1. When abnormal transient overvoltage occurs in the power supply and causes the SPD to conduct and result in a short circuit and melting, it may cause the power supply to trip and lose power in the mild case, or even lead to a serious fire accident in the severe case. Installing a protection switch (or fuse) is to quickly disconnect the circuit when the SPD experiences a short circuit. It should be particularly noted here: This switch must have the ability to interrupt this short-circuit current; otherwise, the consequences will be very serious! 

2. When the SPD deteriorates (due to exposure to lightning current or transient overvoltage), causing the startup voltage to drop below the power supply voltage, the power frequency leakage current will increase rapidly. When this current is only a few amperes, the SPD's thermal trip mechanism can disconnect the circuit. However, when the current exceeds 10A or more, the thermal trip mechanism often fails to disconnect the circuit before the SPD catches fire. This protective switch (or fuse) must be disconnected before the SPD catches fire to prevent the occurrence of a fire.