This method is intended for use in determining the tensile stress of insulation and sheath compounds. It is applicable to the usual grades of rubber and thermoplastic compounds used for insulation and sheaths.
The specimen shall be a piece of the insulation or sheath taken from the inspection unit. The die used to make the specimen shall be sharp and free from nicks in order to prevent leaving ragged edges on the specimen. In the event that the specimen is either too thick or uneven, the piece or a portion of that piece shall be buffed and allowed to rest for 30 minutes before testing. Using a power driven tensile test machine, the insulation is stretched until breakage. At the end of the test, the average wire/cable insulation tensile strength and elongation are identified.