Copper tapes are sometimes useful when you want to be sure that two metallic parts are well connected to each other. Tapes are present in almost all the EMC laboratories and they are usually made of copper which is quite a good electrical conductor. However, manufacturers have the bad habit of adding an adhesive in one of the sides to fix the tape. The problem is that the adhesive material can be non-conductive!

Copper tape
Verify that your copper tape is condutive at the both sides

Tip: before sticking a piece of tape on your equipment, use a multimeter and verify the continuity over the two sides of the tape.