The gray Outdoor Ground Box cover assembly is prewired with (1) 30A L6-30R 240V corrosion-resistant receptacles. CAUTION: All ground box electrical circuits must be protected by a Ground Fault Circuit Interrupter upstream from the ground box.NOTE: Cover must be closed while in use. Use only molded plug and cord assemblies that are rated for outdoor use.NOTE: Maximum length of plug allowed at end of cord is 3'' (76mm).