Thhn In Attic

Follow the row across to the temperature rating for the wire and read the derating percentage.

Thhn in attic.

When there is no flooring to walk on other than the edges of the trusses consider. In your attic or basement look for a 2 x 4 inch beam adjacent to a prominent hard line. In some installations using metal conduit the raceway the conduit boxes and connectors serve as the ground for the circuit. They are similar to the wires you see when you strip the outer sheathing off of nm cable.

This thinner insulation can often lead to a current leakage and even a breakdown during chemical or environmental exposure. Thhn thwn 2 conductors are constructed of annealed soft copper that follows astm b3 and astm b8 standards. Type thhn thwn 2 is permitted for new construction or rewiring for 600 volt applications. Thhn thwn wires are individual insulated and color coded wires.

The 12 gauge wire tw wire in the 52 c attic is derated to 76 percent of its maximum ampacity. Multiply the conductor s ampacity by the derating percentage. Grounding with conduit. 25 amperes x 82 19 amperes.

The cable is insulated with a thermoset plastic jacket pvc that is flame retardant sunlight resistant lead free strong and stable. Thhn uses a thinner pvc insulation which is a key factor in terms of its electrical properties. With a flashlight examine the attic and locate the path that you will use to run the wire between the two locations. The pvc insulation in thhn also creates a toxic smoke when burned therefore making it undesireable in certain applications.

Familiarize yourself with the footing situation. Cut a hole for the electrical box. Type thhn thwn 2 building wire is intended for general purpose applications as defined by the national electrical code nec. Drill a 1 5 inch starter hole on an angle of the the electric box.

In the basement it is the bottom of the wall and is known as floor.