TE Connectivity WireGrip Connectors WireGrip connectors or wire splices with industry standard colour coding for wire sizes 22 AWG to 10 AWG. WireGrip twist-on splices have square-wire spring threads which provide a positive grip for a secure connection and are made from UL 94V-2 flame retardant thermoplastic. Maximum operating temperature of 105°C. Maximum voltage rating for the splices is 600 V for building wiring and 1000 V maximum in light fixtures, luminaries and signs. The blue and grey WireGrip are rated at 300 V. These connectors are for use with copper to copper connections only.