Gives requirements for 'Nyvin' type cables for aircraft wiring which are suitable for circuits where the voltage between conductors, between a conductor and a metal braid surrounding it and between a conductor and the aircraft structure nowhere exceeds 600 volts r.m.s. and in which the frequency does not exceed 1600 c/s. Suitable where, in continuous service, no combination of ambient temperature and conductor current produces a stabilized conductor temperature in excess of 105 Degrees C and fixed wiring in aircraft at temperatures down to -75 Degrees C, but not suitable for severe flexing at temperatures below -30 Degrees C and in areas where ester-base fluids are present.