Silicone rubber

This is completely resistant to moisture and is suitable for temperatures from - 60 celcius to 150 celcius . it is undamaged after repeated subjection to boiling water and low pressure steam .  and is therefore used on hospital equipment which ahs to be sterilized .
  Although it is destroyed by fire , the ash is non-conductive and will continue to serve as insulation if it can be held in place . A braid or tape of glass-silicone rubber will hold it , and cable made with this construction is very useful for fire alarms . Thermosetting rubber of 180 celcius is used in hot -air saunas .

Glass
Glass fibre has good heat-resisting properties and is therefore used for cables which are employed in high-temperature surroundings . One example is the internal wiring of electric ovens . Another application which may not at first sight seem to require heat-resisting cable lies in flexible cords for liminaires . Although the object of an incandescenet lamp is to convert electrical energy into light , most of the energy is in fact dissipated as heat . many luminaires restrict the paths available for the removal of heat and in consequence produce high local temperatues . The high temperatures is transmitted to the flexible ord both by direct conduction through the lamp socket to the conductors and by an increase in the local ambient temperature . if the flexible cord is to last any length of time , it must be capable to withstanding the temperature it is subjected to .
  One type of flexible cord is made from tinned copper conductors insulated with two layers of glass fibre , which is impregnated with varnish . A glass fibre braid , also impregnated with varnish , is applied over the primary insulation . This type of cord can be used at temperatures up to 155 celcius . If it is made with nickel-plated conductors and a silicone-based varnish , it then becomes suitable for temperatures up to 200 celcius .