The LPC 11911-124 is a two terminal lightning and surge protective device for protection of electrical and electronic equipment against surges and overvoltage conditions appearing on the “plus” and “minus” lines of the power system. Maximum continuous operating voltage is 1000 VDC.Response is less than one nanosecond in either polarity. Restoration is automatic at the instant the voltage reduces to the normal operating voltage. There is no follow current, no power voltage dip, no power interruption.This SPD is a metal oxide varistor device. It is maintenance free, not repairable. The failure mode is short circuit. With the occurrence of a destructive surge the SPD is removed from the circuit by a special fuse wire (provided with the SPD). The two terminals are threaded studs (1/4-20 thread). Either terminal may be connected to the “plus” or “minus” bus. The enclosure is black valox plastic.The SPD shall be customer mounted within a suitable metal enclosure to contain any possible flying debris should a failure occur. The location shall be inaccessible to unauthorized personnel. For a sound and realistic installation a multiplicity of fused parallel SPD’s is suggested. This permits the assembly to have uninterrupted continuation of protection with the remaining SPD’s. Another significant advantage of multiple, parallel SPD’s is the extension of life. With two SPD’s in parallel life is extended 3 to 5 times; with three 7 to 20 times; with four 25 to 100 times. For heavy lightning areas it is advisable to use four or more SPD’s in parallel, in view that each SPD is rated for a maximum 30 KA on an 8/20 s lightning wave and that lightning may occasionally exceed 100 KA. Lesser intensity lightning strokes would also require parallel SPD’s, considering that the lightning channel discharges an average of six individual strokes (as many as 40 have been recorded).
