NEMA publishes HP 5 and HP 8 wire standards
The National Electrical Manufacturers Association (NEMA) has published two wire standards: HP 5-2009 “Electrical and Electronic Crosslinked, Modified Polyethylene (XLPE) Insulated 125°C Hook-Up Wire, Types L (600 V), LL (1000 V), and LX (3000 V)” and HP 8-2009 “Electrical and Electronic Crosslinked, Modified Low Smoke Polyolefin (XLPO) Insulated Hook-Up Wire, Types LS (105°C-600 V), ZHDM (90°C-600 V), ZHDH (90°C-600 V), ZH (125°C-600 V), and ZHX (125°C-1000 V)”.
HP 5 was developed to ensure the specified types of hook-up wire can be
procured, and they will meet requirements associated with the commercial
electrical and electronic equipment in which they are used. HP 8
defines hook-up cables using low-smoke and low/zero halogen insulation
materials that could be used as a possible alternative to PVC-insulated
cables for certain applications.