Secondary Telecom Protection

Secondary protectors (stand alone units or integrated into strip protectors and UPSs) are adjunct devices used to enhance the protection level of customer premise equipment (CPE). Due to the inadequate level of protection designed into CPE, secondary protectors often are required to prevent premature failure of equipment exposed to environmental hazards (Figure 3.53). Secondary protectors should be able to withstand overvoltages that can exceed 800 V and surge currents up to 100 A. Figure 3.54 illustrates a SIDACtor device selected because the associated peak pulse current (IPP) is sufficient to withstand the lightning immunity tests of TIA-968-A (formerly known as FCC Part 68) without the additional use of series line impedance. Likewise, Figure 3.54 illustrates a fuse selected because the amps2time (I2t) rating is sufficient to withstand the lightning immunity tests of TIA-968-A, but low enough to pass UL power cross conditions.