multiple conductor electrical power cords , signal transmitting wiring and cable is insulated with one or more layers or sheathing of a thermoplastic polymer composition with at least the outer layer of the composition containing contaminant resistant or combating agents that inhibit growth of biological contamination . the microbial resistant cord or wiring has particularly advantageous utility of power cords for use with appliances or electrical products in facilities that affect health , such as medical and food related facilities that require safeguarding against contaminating microorganism attack formation , or growth .