Stronghold™ ESV Butt Splices Panduit Stronghold™ ESV Butt Splices meet application challenges with minimal installed cost and boast superior electrical performance. These butt splices are rated to 221°F (105°C) and feature insulation support and brazed seam. The ESV Stronghold™ butt splices are UL® listed and CSA certified. These butt splices meet UL/CSA/ABS standards when used with Panduit tools.