Foreign cable manufacturer sand operating engineers have apparently appreciated the reduction in carrying capacity due to dielectric losses as they ordinarily limit their maximum conductor temperature to appoint well below the critical temperature as determined by these investigations. Their publications also appear to indicate that they fully appreciate that the quality of the insulation is of prime importance and that increased security cannot be obtained by increasing the thickness of insulation without improving the quality. The tests on cables made at the factory indicate that with the thicknesses of insulation that are commonly used in this country, and with the insulation of the first quality, the cable will pass the test required by the Standards of the A.I.E.E. with a wide margin of safety.