Follow the row across to the temperature rating for the wire and read the derating percentage.
Thhn in attic.
In the attic the beam is the top of the wall and is called the roof.
Drill a 1 5 inch starter hole on an angle of the the electric box.
Familiarize yourself with the footing situation.
Thhn thwn 2 conductors are constructed of annealed soft copper that follows astm b3 and astm b8 standards.
When there is no flooring to walk on other than the edges of the trusses consider.
They are similar to the wires you see when you strip the outer sheathing off of nm cable.
Type thhn thwn 2 building wire is intended for general purpose applications as defined by the national electrical code nec.
Applications requiring type thhn or thwn 2 the conductor is appropriate for use in wet or dry locations at temperatures not to.
Thhn uses a thinner pvc insulation which is a key factor in terms of its electrical properties.
The pvc insulation in thhn also creates a toxic smoke when burned therefore making it undesireable in certain applications.
Climb through the attic access using a ladder if necessary and look into the attic space.
Thhn thwn wires are individual insulated and color coded wires.
Cut a hole for the electrical box.
In your attic or basement look for a 2 x 4 inch beam adjacent to a prominent hard line.
With a flashlight examine the attic and locate the path that you will use to run the wire between the two locations.
The cable is insulated with a thermoset plastic jacket pvc that is flame retardant sunlight resistant lead free strong and stable.
Grounding with conduit.
In the basement it is the bottom of the wall and is known as floor.
Multiply the conductor s ampacity by the derating percentage.
Type thhn thwn 2 is permitted for new construction or rewiring for 600 volt applications.
25 amperes x 82 19 amperes.