Correctly specified and installed, high temperature cable will last longer at its rated temperature than a low temperature cable in the same application. How much longer? High temperature cables that are correctly specified and installed should provide trouble-free service for many years. Often, these cables have an initial cost that appears to be significantly greater than a low temperature alternative. Once installed, however, the true installed cost becomes apparent. A bargain cable that must be replaced a dozen times may not be a bargain. One rule of thumb frequently applied to wire & cable is that for every 5 degrees Centigrade that the rated temperature is exceeded, the useful service life is cut by half. This means that a typical portable cable rated 90 C installed in a 250 C ambient temperature probably will fail within 8 to 10 hours!