Abstract: To protect electronic apparatus against voltage peaks, in particular those generated by nuclear electromagnetic pulses (NEMP), several lowpass filters with voltage-limiting elements are interposed in the system of lines entering from outside, and are built into a housing with an electrically conducting inside wall and divided into several compartments. The lowpass filters flatten out the leading edge of an entering overvoltage peak to such an extent that the last voltage-limiting devices in the series circuit are actuated at the proper time so as to effectively limit the overvoltage peaks, while the incorporation of the electrical elements in the housing with separated compartments avoids overcoupling of high-frequency signal components.