What type of tie should be used on bare copper conductors?

• A. Aluminum tie, insulated
• B. Copper tie, bare, soft annealed
• C. Aluminum tie, insulated, preformed
• D. Copper tie, bare hard annealed

Answer: (B)

When fastening bare copper conductors, use a tie that will not damage the conductor or cause corrosion. A copper tie that is bare and soft annealed matches the conductor material, allows a gentle, secure wrap, and won’t nick or score the copper. Hard annealed copper is too stiff and can crush or crack the conductor. Aluminum ties, even if insulated, are avoided with copper because dissimilar metals in contact promote galvanic corrosion and uneven gripping. Insulation isn’t needed on ties for bare conductors and can trap moisture. So the best choice is a copper tie, bare, soft annealed.