[en] An attempt is being made to assess complete electrical failure of signal and low-power cables typically used in nuclear power plant containments and to correlate failure modes with the mechanical deterioration of the elastomeric cable material. Work over the past 24 months, although limited to one cable configuration, has identified creep shortout and insulator cracking, both aggravated by mechanical stresses, as the phenomena most likely to cause electrical breakdown. Comprehensive tests have been run for six months and are continuing. Preliminary conclusions can be drawn and are reported