Yes, Telect offers an electrical isolator for 5/8" all-thread. P/N E70282 is the red isolator knob, and P/N 01050-07 includes 12" of all-thread and the brackets shown in the below photo. Telect also offers a 48" all-thread version (P/N 01050-10) and a 24" all-thread version (P/N 01050-08).