1.1 This guide covers sampling of carbon cathode blocks used in the production of aluminum, and details procedures for taking samples from single cathode blocks. It covers equipment and procedures for obtaining samples from cathode blocks in a manner that does not destroy the cathode block or prevent its subsequent use as originally intended. However, the user must determine the subsequent use of the sampled cathode blocks. Preferred locations for taking samples from single units of cathode blocks are covered in this guide.