Thhncu-generic thhn300mcmstrgrymr Thhn 300 Kcmil Copper Wire

Product Description

The THHNCU-GENERIC thhn300mcmstrgrymr is a 300 kcmil stranded copper conductor THHN building wire with gray PVC insulation and a nylon jacket. Rated for 600 volts and up to 90 degrees C in dry environments, it carries up to 320 amps at 90 degrees C, making it suitable for high-ampacity feeder and branch-circuit runs. The 37-strand construction adds flexibility for pulling through conduit in tight commercial and industrial installations. Licensed electricians and electrical contractors install this wire type in accordance with NEC requirements for conduit-enclosed wiring systems.

This wire is used in residential service entrances, commercial panel feeds, and industrial feeder applications where a large-gauge, high-ampacity conductor is required. The gray insulation color supports phase identification and color-coding practices on multi-conductor runs. Cut-to-length availability reduces waste on job sites where a full reel is not required. Typical applications include feeder runs from main distribution panels, motor circuit feeds, and large appliance branch circuits installed in metallic or non-metallic conduit.

Key Features

• 300 kcmil copper conductor with 37-strand construction for flexibility in conduit pulls
• 600-volt rating suitable for standard commercial and residential power distribution
• Ampacity of 240 amps at 60 degrees C, 285 amps at 75 degrees C, and 320 amps at 90 degrees C
• 90 degrees C dry temperature rating for demanding installation environments
• Gray PVC insulation with nylon jacket for abrasion resistance and pull-through durability
• Cut-to-length format reduces material waste on custom feeder runs

Compatibility

Designed for use in conduit-enclosed wiring systems where THHN-rated 300 kcmil copper conductor is specified. Suitable for NEC-compliant feeder and branch-circuit installations in dry conduit environments rated for 600 volts or less.

Installation Notes

Installation must be performed by a licensed electrician in accordance with applicable NEC articles and local electrical codes. De-energize and lock out the circuit or panel before making any connections. THHN wire must be installed inside an approved conduit or raceway — direct burial and wet locations require a wire type rated for those conditions. Use appropriately rated lugs, terminals, and connectors sized for 300 kcmil conductors.